Journal of Mammalogy, 97(3):663–688, 2016
DOI:10.1093/jmammal/gyw078
Published online May 28, 20162016 Guidelines of the American Society of Mammalogists for theuse of wild mammals in research and education
Robert S. Sikes* and the Animal Care and Use Committee of the American Society of Mammalogists†
Basic Animal Services Unit, Department of Biology, University of Arkansas at Little Rock, 2801 South University Avenue, Little
Rock, AR 72204, USA (RSS)John A. Bryan II, SCWDS/University of Georgia; David Byman, Pennsylvania State University–Worthington; Brent J. Danielson, Iowa
State University; Janna Eggleston, Old Dominion University; Michael R. Gannon, Pennsylvania State University–Altoona; William
L. Gannon, University of New Mexico; David W. Hale, United States Air Force Academy; Brett R. Jesmer, University of Wyoming; Daniel
K. Odell, Hubbs–SeaWorld Research Institute; Link E. Olson, University of Alaska Fairbanks; Richard D. Stevens, Texas Tech University;
Tracy A. Thompson, United States National Park Service; Robert M. Timm, University of Kansas; Stephanie A. Trewhitt, San Jose State
University; Janna R. Willoughby, Purdue University.
†

Guidelines for use of wild mammal species in research are updated from Sikes et al. (2011). These guidelines covercurrent professional techniques and regulations involving the use of mammals in research and teaching; they also
incorporate new resources, procedural summaries, and reporting requirements. Included are details on capturing,marking, housing, and humanely killing wild mammals. It is recommended that Institutional Animal Care and
Use Committees (IACUCs), regulatory agencies, and investigators use these guidelines as a resource for protocols
involving wild mammals, whether studied in the field or in captivity. These guidelines were prepared and approvedby the American Society of Mammalogists (ASM), in consultation with professional veterinarians experienced inwildlife research and IACUCs, whose collective expertise provides a broad and comprehensive understanding of thebiology of nondomesticated mammals. The current version of these guidelines and any subsequent modifications
are available online on the Animal Care and Use Committee page of the ASM website (http://mammalogy.org/
uploads/committee_files/CurrentGuidelines.pdf). Additional resources pertaining to the use of wild animals in
research are available at: http://www.mammalsociety.org/committees/animal-care-and-use#tab3.

ResumenLos lineamientos para el uso de especies de mamíferos de vida silvestre en la investigación con base en Sikes
et al. (2011) se actualizaron. Dichos lineamientos cubren técnicas y regulaciones profesionales actuales que
involucran el uso de mamíferos en la investigación y enseñanza; también incorporan recursos nuevos, resúmenes
de procedimientos y requisitos para reportes. Se incluyen detalles acerca de captura, marcaje, manutención encautiverio y eutanasia de mamíferos de vida silvestre. Se recomienda que los comités institucionales de uso y cuidado
animal (cifras en inglés: IACUCs), las agencias reguladoras y los investigadores se adhieran a dichos lineamientos
como fuente base de protocolos que involucren mamíferos de vida silvestre, ya sea investigaciones de campo oen cautiverio. Dichos lineamientos fueron preparados y aprobados por la ASM, en consulta con profesionales
veterinarios experimentados en investigaciones de vida silvestre y IACUCS, de quienes cuya experiencia colectiva
provee un entendimiento amplio y exhaustivo de la biología de mamíferos no-domesticados. La presente versiónde los lineamientos y modificaciones posteriores están disponibles en línea en la página web de la ASM, bajo
Cuidado Animal y Comité de Uso: (http://mammalogy.org/uploads/committee_files/CurrentGuidelines.pdf).
Recursos adicionales relacionados con el uso de animales de vida silvestre para la investigación se encuentran
disponibles en (http://www.mammalsociety.org/committees/animal-care-and-use#tab3).

© The Author 2016. Published by Oxford University Press on behalf of American Society of Mammalogists.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium,provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
663

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* Correspondent: rssikes@ualr.edu

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JOURNAL OF MAMMALOGY
Key words: animal capture, animal care, animal housing, animal marking, animal use ethics, federal regulation, Institutional Animal
Care and Use Committee, trapping

Organization of Guidelines

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Overview ����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������665
Development of the American Society of Mammalogist Guidelines ����������������������������������������������������������������������������������������665
Role of the Veterinarian ������������������������������������������������������������������������������������������������������������������������������������������������������������666
Tailoring Oversight to Wildlife Research ����������������������������������������������������������������������������������������������������������������������������������666
Regulation of Animal Activities ������������������������������������������������������������������������������������������������������������������������������������������������667
Categorization of Animal Use for USDA Compliance ������������������������������������������������������������������������������������������������������������669
USDA reports: pain and distress categories ������������������������������������������������������������������������������������������������������������������������669
USDA classifications as applied to animal capture and noninvasive field procedures ��������������������������������������������������������669
Euthanasia and humane killing ��������������������������������������������������������������������������������������������������������������������������������������������670
Field studies ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������670
Protocols and Protocol Forms for Wildlife Studies ������������������������������������������������������������������������������������������������������������������670
Numbers and Species (Including Endangered Taxa) ����������������������������������������������������������������������������������������������������������������671
General Guidelines ����������������������������������������������������������������������������������������������������������������������������������������������������������������������672
Fieldwork with Mammals ��������������������������������������������������������������������������������������������������������������������������������������������������������672
Training ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������672
Oversight of Field Studies ��������������������������������������������������������������������������������������������������������������������������������������������������������672
Trapping Techniques ����������������������������������������������������������������������������������������������������������������������������������������������������������������������672
Considerations for capturing mammals ������������������������������������������������������������������������������������������������������������������������������������672
Live capture ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������673
Capture myopathy and injuries ������������������������������������������������������������������������������������������������������������������������������������������������674
Kill traps and shooting ��������������������������������������������������������������������������������������������������������������������������������������������������������������675
Drowning in conjunction with other trapping methods ������������������������������������������������������������������������������������������������������������675
Marine mammals ����������������������������������������������������������������������������������������������������������������������������������������������������������������������676
Use of domestic dogs in research ����������������������������������������������������������������������������������������������������������������������������������������������676
Tissue sampling and Identification ����������������������������������������������������������������������������������������������������������������������������������������������676
Tissue sampling ������������������������������������������������������������������������������������������������������������������������������������������������������������������������676
Obtaining blood form the facial vein ����������������������������������������������������������������������������������������������������������������������������������677
Obtaining blood form the caudal vein ����������������������������������������������������������������������������������������������������������������������������������677
Obtaining blood from the retro–orbital sinus ����������������������������������������������������������������������������������������������������������������������677
External marks ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������677
Internal tags ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������678
Chemical immobilization for application of marks and tissue sampling������������������������������������������������������������������������������������678
Maintenance of Wild-caught Mammals in Captivity ������������������������������������������������������������������������������������������������������������������679
Procurement and holding conditions ����������������������������������������������������������������������������������������������������������������������������������������679
Maintenance environments ������������������������������������������������������������������������������������������������������������������������������������������������������679
Environmental enrichment ��������������������������������������������������������������������������������������������������������������������������������������������������������680
Captive housing of bats ������������������������������������������������������������������������������������������������������������������������������������������������������������680
Observation intervals for captive wild mammals ����������������������������������������������������������������������������������������������������������������������681
Separation of taxa and minimizing stress ���������������������������������������������������������������������������������������������������������������������������������681
Release of captive mammals ����������������������������������������������������������������������������������������������������������������������������������������������������681
Euthanasia and Humane Killing ��������������������������������������������������������������������������������������������������������������������������������������������������682
Vouchering of Specimens and Ancillary Materials ��������������������������������������������������������������������������������������������������������������������684
Human Safety ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������684
Summary ����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������684
Acknowledgments ������������������������������������������������������������������������������������������������������������������������������������������������������������������������685
Literature Cited ����������������������������������������������������������������������������������������������������������������������������������������������������������������������������685

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

Overview

revision of the Guide states that “[t]he Guide does not purport
to be a compendium of all information regarding field biology
and methods used in wildlife investigations, but the basic principles of humane care and use apply to animals living undernatural conditions” and encourages readers to consult qualified wildlife researchers and taxon specialists for additional
information.
This and all recent editions of the ASM guidelines include
information from the United States and other governments (e.g.,
Canadian Council on Animal Care 1993) as well as other professional sources where appropriate, such as the Society for the
Study of Animal Behaviour (2006), the American Veterinary
Medical Association (AVMA 2013a) Guidelines for the
Euthanasia of Animals, and primary literature. The information
contained herein is consistent with existing United States regulations regarding the care and use of vertebrate animals in researchand education. Sikes et al. (2012), Sikes and Bryan (2015), andWingfield (2015) argue that the ethical and appropriate oversightof animal activities requires guidance tailored to the species andconditions involved, and that the appropriate standards for wildlife research are the taxon-specific guidelines prepared by thevarious taxon-oriented professional societies. The NSF agrees
with this conclusion, as evidenced by recent (2013) changes to
its Grant Proposal Guide (http://www.nsf.gov/pubs/policydocs/
pappguide/nsf15001/gpg_print.pdf) which states that:In the case of research involving the study of wildlife
in the field or in the lab, for the provision in the PHS
Assurance for Institutional Commitment (Section II)
that requires the organization to establish and maintaina program for activities involving animals in accordancewith the Guide for the Care and Use of Laboratory Animals (Guide), the organization has established and will
maintain a program for activities involving animals according to the Guide. The organization will follow recommendations specified in the Guide for details involving laboratory animals, and taxon-specific guidelines
approved by the American Society of Ichthyologists andHerpetologists, the American Society of Mammalogists,
and the Ornithological Council, as is appropriate for thetaxon to be studied.
The acceptance of these guidelines is further evidenced by thefact that AAALAC International, an independent organizationcommitted to peer-reviewed assessment and accreditation ofanimal care programs, adopted the previous (2011) version of
the ASM guidelines as a reference document for use by accredited institutions.
The revised guidelines herein are intended to provide investigators and those charged with evaluating animal use in research(e.g., Institutional Animal Care and Use Committees [IACUCs],
reviewers and editors of research manuscripts, management
agency personnel, graduate committees, and the public) with upto-date guidance on ethical care and use issues as well as health,safety, and environmental concerns particular to nondomesticatedmammals. These guidelines do not provide details concerning
how IACUCs are to be constituted or operate, and thus are notintended to replace the Guide on these matters. We underscore

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Development of the American Society of
Mammalogist guidelines
Advances in the study of mammals—from exploring physiological functions to understanding evolutionary relationships and developing management strategies—are predicatedon responsible use of animals in research. Founded in April
1919, the American Society of Mammalogists (ASM) is deeply
concerned with the welfare of mammals and, in particular,
the persistence of natural communities of organisms. In 1928,
Joseph Grinnell—one of the founders of the ASM—instructedadministrators of Yosemite National Park to maintain the Park
as a natural mammalian community without unnecessary or
destructive development. Grinnell (1928:76) described various management tactics for Park managers to follow; in particular, he advised that to address an unwanted increase in thebear population, Park officials needed to “devise [some] means
whereby troublesome individual bears could be discouraged
from raiding food-stores, without doing them serious bodily
harm. But I recommend that exceeding care be taken in suchprocedure, not to rouse, unnecessarily, adverse public opinion,
and not to drive away the bears altogether, for they constitutea particularly valuable element in the native animal life of thevalley.” Thus, Grinnell made informed management recommendations that advocated humane animal care and use withsensitivity toward public opinion. The same is true today asmammalogists work to understand and to protect the sentientorganisms they study.
The ASM publication Guidelines for the Use of Animals
in Research (ad hoc Committee for Animal Care Guidelines
1985) was the 1st effort to codify the expertise and philosophy of experienced, professional mammalogists regarding theuse of mammals in research. This single-page statement listed
broad considerations, such as concern for numbers of animals used, and highlighted laws that regulated use of animals
and available standards. It stated that the investigator should
exercise good judgment and prudence when using animals
in research. More complete guidance was published by the
ASM in 1987 with Acceptable Field Methods in Mammalogy:
Preliminary Guidelines Approved by the American Societyof Mammalogists (ad hoc Committee on Acceptable Field
Methods in Mammalogy 1987, http://mammalogy.org/uploads/
committee_files/ACUC1987.pdf). The 1987 ASM guidelines, along with those for birds, reptiles and amphibians, andfishes (produced by the other taxon-based professional organizations) were developed at the request of the United States
National Science Foundation (NSF) specifically because guidance relevant to wild vertebrates was not available in the 1985
version of the National Research Council’s (NRC) Guide for
the Care and Use of Laboratory Animals (hereinafter Guide)(Orlans 1988). Conduct of animal care programs consistent
with the Guide became required for activities funded by theUnited States Public Health Services (PHS) under the HealthResearch Extension Act of 1985, but neither the 1985 version nor subsequent editions of the Guide provided specificguidance for wild vertebrates. Even the most recent (2011:32)

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the fact that fundamental and profound differences exist between
activities involving wild mammals, particularly in their natural
habitat, and activities with traditional research and domesticatedanimals in laboratory settings. These differences are detailed elsewhere (Sikes et al. 2012; Sikes and Paul 2013; Sikes and Bryan2015) and include consideration of appropriate methods foreuthanasia or humane killing, the potential for impacts on natural populations, differences in biology of the animals themselves,and differences in handling and husbandry requirements.

1. No person may practice veterinary medicine in the State
except within the context of a veterinarian–client–patient
relationship [VCPR].
2. A veterinarian–client–patient relationship cannot be established solely by telephonic or other electronic means.
Commentary by the AVMA for this section emphasizes “…
that because a VCPR requires the veterinarian to examine thepatient, it cannot be adequately established by telephonic orother electronic means (i.e., via telemedicine) alone.” Thus,
for most wildlife research, the veterinarian serves as a valued adviser and consultant during the planning stages or in
response to challenges encountered during field activities that
stimulate procedural refinements prior to additional activities.
It must be stressed that the selection, dosages, and administration routes of pharmaceuticals are best accomplished in consultation with veterinarians having appropriate wildlife experienceand expertise, and that this consultation must be prior to useof these compounds. Because the role of the veterinarian infield activities is not necessarily consistent with the expectations of the Guide (NRC 2011) and because the Guide provides
little or no information relevant to issues of primary concern
in wildlife investigations (Sikes et al. 2012; Paul and Sikes
2013; Sikes and Paul 2013; Paul et al. 2015; Sikes and Bryan2015), IACUCs should consider whether these fundamental
differences in and of themselves constitute justification for an
IACUC-approved departure from the Guide. PHS policy (seesection below on “Regulation of animal activities”) specifies
that “…the research project is consistent with the Guide unlessacceptable justification for a departure is presented” (National
Institutes of Health/Office of Laboratory Animal Welfare [NIH/
OLAW] 2015). The Model Wildlife Protocol endorsed by the
ASM in 2016 (available at http://mammalogy.org/uploads/

Tailoring oversight to wildlife research
Oversight of animal use in research and education has almost
universally developed from a biomedical perspective in which
research was focused on human health and research questions
were addressed using domesticated animal models in laboratoryenvironments. Once regulations, guidelines, and expectations
were established for oversight of these activities, they were often
extended to apply to the study of wild animals in their native environments. This progression is not surprising given the importanceand visibility of biomedical research and the number of animals
used in such studies but, beyond the basic goals of ensuring
humane treatment and minimizing pain or distress, guidelines andregulations designed for biomedical research have little relevanceto research on wild animals, particularly in their natural environment. Indeed, using guidance not designed for wild animals will
most likely result in ineffective or even inhumane treatment ofthese taxa. This disconnect occurs because of fundamental differences in the goals of biomedical and wildlife research, the role ofanimals in these respective research endeavors, and in particular
because of fundamental differences between the domesticatedanimals most often used in biomedical work and the wild subjects
used in field research. Consequently, unless guidance documents
and expectations are modified extensively before they are applied
to wild animals, their utility for biologically appropriate oversightof wild mammals is at best limited and at worst harmful to theanimals they are intended to protect.
Sikes and Paul (2013) emphasized many of the obvious differences between biomedical and wildlife research. These include
the fact that, rather than using animals as surrogates for humans
in studies designed to benefit human health, studies of wildlife
are often designed to benefit the study subjects. Individual animals are not so much “used” as they are the objects of study inprojects designed to understand various aspects of their biology,
including their behavior, ecology, and evolutionary diversification. A 2nd significant difference is that studies of wild animals, particularly those in their natural environments, have thepotential for impacts beyond the study subjects because theseDownloaded from http://jmammal.oxfordjournals.org/ by guest on June 10, 2016

Role of the veterinarian
Except in those projects in which investigators are themselves
veterinarians or in which veterinarians accompany investigators during all field activities with wild animals, the role ofveterinarians in wildlife research will differ substantially fromtheir roles in laboratory research. Because the veterinarian
seldom, if ever, accompanies investigators during their field
activities, unless the animals can be transported to the veterinarian, the veterinarian could provide medical advice for a specific animal based only upon observations by field personnel.
Such actions are not consistent with Section 5 of the model
Veterinary Practices Act endorsed by the AVMA (2013b).
Section 5 states that:committee_files/ModelWildlifeProtocol2016.docx) provides 1
mechanism to facilitate presentation and approval of departuresfrom the Guide for wildlife activities.
These guidelines are designed to highlight the concerns one
must address within the existing regulatory framework when
conducting research and educational activities involving wild
mammals. This document is not intended as an exhaustive listof acceptable procedures or issues in all circumstances or withall species. Our goal is to focus attention on the types of issues
that should be considered when working with wild mammals andprovide resources for addressing those concerns. We emphasizethat these guidelines are not intended to constrain ingenuity inmeeting research demands, but rather to bring relevant safety,
regulatory, and ethical concerns regarding the use of wild mammals to the attention of investigators and oversight bodies. It is the
responsibility of the principal investigator (PI) of a project to justify deviations from federal regulations or other applicable guidance during submission of a protocol to the cognizant IACUC.

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

oversight body includes wildlife expertise, the diversity of species and research foci encompassed by such research will likely
generate occasions when outside consultation is warranted. In
these cases, the Animal Care and Use Committee (ACUC) of theASM can assist in identifying individuals with relevant expertise.
Regulation of animal activities
The use of vertebrate animals, particularly mammals, in researchand education is regulated in many countries. In the UnitedStates, mammals other than rats of the genus Rattus and miceof the genus Mus that have been bred for research are regulatedby the United States Department of Agriculture Animal and
Plant Health Inspection Services (USDA/APHIS). The USDA
recognizes exemptions, however, for those studies that meetthe definition of a field study as defined by the Animal Welfare
Act (AWA, see below). In addition to regulation by the USDA,
activities funded by PHS must also comply with relevant provisions of the PHS policies on humane care and use of laboratory
animals (NIH/OLAW 2015). Institutions receiving PHS funding involving animal use or assured by the NIH/OLAW must
maintain a PHS Assurance with the NIH/OLAW stating that,at a minimum, all PHS-funded activities will be conducted ina manner consistent with the Guide and the AVMA Guidelines
for Euthanasia of Animals. If they choose, institutions may voluntarily extend their PHS Assurance so that it applies to all animal activities rather than only those funded by the PHS. The
negative consequences of these latter cases is that all activities,
regardless of the source of funding or intellectual focus, must be
conducted in a manner consistent with the Guide and the AVMA
guidelines for euthanasia, both of which are often poorly suited
for work with wild animals in the field. It is critical for oversight
personnel and investigators to be familiar with the wording of
their PHS Assurance to ensure continued compliance with theregulations and policies covering animal use.
Mammalogists conducting virtually any type of research
involving wild mammals at an institution subject to federal oversight will be required to consult with their IACUCs to determine if their planned activities are subject to IACUC review
and approval; in other words, whether the proposed activities
meet the regulatory definition of a “field study” (see below).
Investigators are also responsible for procuring all necessary permits from local and federal agencies before conducting any procedure involving live animals. These permit requirements apply
whether the PI is working within the United States or elsewhere.
The AWA authorizes the USDA/APHIS to regulate vertebrates used (or intended for use) in research, testing, experimentation, exhibition, or as pets, regardless of whether animals
are maintained in a laboratory, wild enclosure, or farm setting.
However, the USDA/APHIS does not regulate animals used forfood or fiber (or for improving quality of food or fiber), or for
improvement of animal nutrition, breeding, management, or
production efficiency. As noted above, there also is an exemption for activities that meet the regulatory definition of a fieldstudy. It is critical to note that the determination as to whether
the proposed activities will meet the definition of a field study
should be made by the IACUC rather than the researcher.

Downloaded from http://jmammal.oxfordjournals.org/ by guest on June 10, 2016individuals exist as part of a population and a community. A 3rd
difference is that, whereas most biomedical research is conducted with only a few species of purpose-bred mammals, there
are more than 5,400 species of wild mammals that are potential
subjects of field studies. Closely related species can differ withregard to habitat, handling needs, or husbandry requirements
and even wildlife veterinarians are unlikely to have experience
with more than a small number of these taxa.
Underlying the marked differences in focus and scope
between biomedical and wildlife research are profound differences in virtually every aspect of the biology of domesticatedanimals versus wild taxa. The act of domestication produces
animals that interact very differently with humans compared towild strains. For example, rather than fearing and fleeing fromhumans, domesticated animals look to us for food, shelter, andoften companionship. As Darwin (1868) noted, captive propagation of wild taxa selects for behavioral and morphological traits
favored by humans and relaxes selection for traits important forsurvival in the wild. His observations and our understanding of
the genetic basis of these differences led to development of thedomesticated strains of animals and plants that form the basis ofmodern agriculture. Thus, although pet dogs belong to the same
species as the wolf, Canis lupus (Wilson and Reeder 2005),
they clearly differ dramatically from wolves with regard to theirinteractions with humans. The changes in behavior, morphology, and genome diversity that are part of the domestication
process may become evident after remarkably few generations.
Lacy et al. (2013) and Willoughby et al. (2015) demonstrated
behavioral and genetic changes among captive populations ofwild rodents subjected to different breeding regimes after only
6–20 generations, even when breeding protocols were designed
to limit evolution in captivity. Importantly, Lacy et al. (2013)
also found significant correlations among behavioral and life
history parameters such as reproductive success. Other studies of the domestication process have demonstrated associated changes in interactions with humans (Hare et al. 2005),
hormonal profiles, and stress responses. Even seemingly subtle selection for “tameability” can have profound influences(Trut et al. 2009), resulting in domestic ferrets that are more“dog-like” than “wild ferret-like” with respect to their socialaffiliative behavior and responsiveness to humans (Hernádi
et al. 2012), and captive bred-foxes that display dog-like characteristics (e.g., eager to attract human interaction) after only
a few generations (Belyaev and Trut 1964). If such changes
are evident after only a few generations or decades of captive
breeding, how much stronger are the changes associated withextended selection, such as that experienced by traditional
laboratory study subjects? Or, perhaps more relevant to workwith wild animals, why would one expect wildlife species to
respond to stimuli in the same manner as domesticated strains?
Institutions conducting wildlife research should ensure that
the IACUC review process includes personnel with appropriate
expertise. In many instances, this need is met by having one ormore field researchers on the oversight committee. At institutions
where field research accounts for a small proportion of protocols, outside consultation can be particularly useful. Even if the

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if species are listed in CITES Appendices I–III, the Endangered
Species Act, Lacey Act, or the Marine Mammal Protection Act.
Note, however, that CITES-listed materials can move without
permit between 2 registered institutions provided that they werefirst accessioned by the sending institution. Investigators should
expect similar regulations in other countries and ensure compliance with all applicable regulations dealing with species of
special concern. Investigators also must ascertain whether additional permits are needed when they review state–provincial andfederal–national laws and regulations that relate to their planned
field investigations. Further, investigators must be familiar withcurrent lists of mammalian species deemed threatened or endangered by appropriate state–provincial or federal–national governments and comply with all laws and regulations pertaining
to capture of these and other categories of protected mammals.
A list of threatened or endangered species and subspecies under
the United States Endangered Species Act is available fromthe Office of Endangered Species, Fish and Wildlife Service,
United States Department of the Interior, Washington, D.C.
20240 (http://www.fws.gov/endangered/). Regulations relevantto these taxa are published in the Code of Federal Regulations,
50 CFR Part 17; amendments to regulations under Title 50 also
are published in the Federal Register. Investigators can search
for CITES-listed species at http://checklist.cites.org/#/en.
Most states and provinces require scientific collecting permits, and investigators must comply with these requirements
and other regulations imposed by agencies in the states or provinces in which they conduct fieldwork in addition to all national
and international regulations. States, national and state parks, orother organizations might have additional regulations regarding
scientific uses of wildlife on lands under their jurisdiction. All
public lands require permits except those lands controlled by theUnited States Bureau of Land Management, which still requires
permission from a District Ranger. Compliance with these regulations and permit requirements is essential. With regard to privately owned land, investigators should obtain permission fromthe owner, operator, or manager before commencing fieldwork.
Many institutions, and state, provincial, and federal governments, have regulations or recommendations concerning handling and sampling of rodents or other mammals that might
be carriers of zoonotic diseases. Investigators must ensure theirown safety and that of employees or students by recognizing the disease-carrying potential of the mammals they study.
Additionally, as part of their charge of reducing institutional liability, most IACUCs have adopted some form of occupational
health screening for all persons involved with animal research.
Health screening can range from completion of a simple checkoff form inquiring about allergies or other health conditionsof investigators, students, and employees, to completion of amuch more detailed medical examination and health history.
The variety and number of permits required for work withwild animals is extensive and has no parallel within the biomedical community. Paul and Sikes (2013) review generalpermitting requirements, but no single document will cover all
possible situations. The PI and the oversight body must be wellversed regarding required permits. This raises the question of

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The United States Fish and Wildlife Service (USFWS) defines
a mammal, in the context of “take,” “possession,” “transportation,” etc., as any member of the class Mammalia, including any
part, product, egg, or offspring, or the dead body or parts thereof(excluding fossils), whether or not included in a manufactured
product or in a processed food product (50 CFR 10.11). In thecontext of regulatory requirements, “permit” is any document
designated as a “permit,” “license,” “certificate,” or any otherdocument issued by the USFWS to authorize, limit, or describe
an activity and signed by an authorized official of the USFWS.
Although the focus of this section is on federal and state regulations in the United States, investigators, regardless of theirnationality or location of their research, should understand that
local, state–provincial, federal–national, or international laws
or regulations likely exist that pertain to scientific collecting,transport, possession, sale, purchase, barter, exportation andimportation of specimens or parts thereof, or other activities
involving native or nonnative species of mammals. Therefore,
each investigator must have knowledge of, and comply with,all relevant laws and regulations pertaining to field collection of
mammals and the places where fieldwork is being conducted.
Federal regulations exist in the United States that pertain to collection, import, export, and transport of scientific specimens ofmammals (Endangered Species Act, CITES, and the Lacey Act).
These regulations have provisions that allow for civil or criminal
penalties and ineligibility for future permits. Researchers living in or conducting research in the United States must obtain
permits issued by federal agencies to: import or export specimens of non-endangered species through a nondesignated portof entry; import or export endangered wildlife through any port;
import injurious wildlife (those species listed under 50 CFRPart 16); import, export, transport interstate commercially, take,harass or possess endangered species listed under 50 CFR Part17, or parts thereof, for research or propagation; take, harass,possess, or transport marine mammals (50 CFR Part 18); importor transfer etiological agents or vectors of human disease or living nonhuman primates; collect scientific specimens on national
wildlife refuges; import ruminants and swine, including parts,
products, and by-products; and import organisms or vectors, tissue cultures, cell lines, blood, and sera. Additional restrictions
on importations of mammals, including fluids or tissues, may
be imposed by the Centers for Disease Control and Prevention(CDC) or USDA/APHIS, so it is imperative that investigators
consult current lists before attempting importation.
Importantly, investigators and IACUCs should be aware thatthe term “scientific collecting” is typically used by state gameagencies in a very different context than by many researchers,
who consider “scientific collecting” as removal of individuals
from the population. In almost all cases, a state permit will be
required for any work with wild vertebrates, whether the animals are removed from the population or not.
When moving specimens of mammals into or out of the UnitedStates, researchers are required to file USFWS form 3–177—currently the electronic declaration form (e-Dec) available at www.
fws.gov is preferred and may be mandatory at the regional officeor port of entry—and any necessary permits required by CITESSIKES ET AL.—GUIDELINES FOR ANIMAL USE

Categorization of animal use for USDA compliance
In 2010, the ASM, in conjunction with the Ornithological Council, reviewed guidance documents available
to institutions and developed a joint position regarding
categorization of animal use for USDA compliance.
This text was first disseminated as a position statement
and addendum to the 2007 version of these Guidelines
in 2010. The portions of this joint position relevant towork with mammals are included herein.
Two aspects of the terminology used to classify animal usage
can cause confusion for activities involving wild animals: classification of the capture of free-ranging animals with regard to
the USDA reporting categories for pain and distress and identification of field studies for the purpose of determining when
IACUC protocol review, IACUC site inspection, and inclusion
on USDA annual reports are required.
USDA reports: pain and distress categories.—The AWA [7
USC 2143(b) (3) (A)] and the implementing regulation (9 CFR
2.36) require that research facilities in the United States subject
to these laws file an annual report with the USDA Animal CareRegional Office documenting their research and teaching activities that use live animals covered by the Act and its implementing regulations. A component of this report is classification ofanimal usage into categories intended to describe the absence,
presence, or extent of pain or distress and the use or non-use ofdrugs to alleviate these conditions.
USDA descriptions for animal reporting categories as definedon the reporting form (APHIS Form 7023) are:
C—Animals upon which teaching, research, experiments or
tests were conducted involving no pain, distress, or use ofpain-relieving drugs.

D—Animals upon which experiments, teaching, research, surgery, or tests were conducted involving accompanying
pain or distress to the animals and for which appropriate
anesthetic, analgesic, or tranquilizing drugs were used.
E—Animals upon which teaching, experiments, research, surgery, or tests were conducted involving accompanying
pain or distress to the animals and for which the use of
appropriate anesthetic, analgesic, or tranquilizing drugs
would have adversely affected the procedures, results, orinterpretation of the teaching, research, or experiments,
surgery, or tests. (An explanation of the procedures producing pain or distress on these animals and the reasons
such drugs were not used must be attached to the report).
Guidance for classifying animal procedures is provided in
Policy 11 of the Animal Care Policy Manual (USDA 2015a)
published by the Animal Care program of the USDA/APHIS.
However, this guidance and the examples therein pertain primarily to procedures conducted in a laboratory setting, usuallyin the context of biomedical research. Classification becomes
especially problematic when institutions are faced with applying regulations intended primarily for laboratory settings anddomesticated animals to the very different context of freeranging wild animals. The 2 critical terms in these descriptions are “pain” and “distress.” According to the Animal Care
Policy Manual Policy 11 (USDA 2015a), a painful procedure isdefined as “any procedure that would reasonably be expected
to cause more than slight or momentary pain or distress in ahuman being to which that procedure is applied, that is, pain inexcess of that caused by injections or other minor procedures.”
Distress is not defined in current policy except by example:“Food or water deprivation beyond that necessary for normal
presurgical preparation, noxious electrical shock that is not
immediately escapable, paralysis or immobility in a conscious
animal.” Appropriate classification of activities is left to the
IACUC.
USDA classifications as applied to animal capture andnoninvasive field procedures.—Mammal capture devices aredesigned either to hold the animal unharmed (live traps) or tokill the animal outright upon capture. Barring mechanical malfunctions, and with appropriate placement and trap monitoring,
animals captured in live traps or nets are simply held without injury until removal. Appropriate training is essential for
setting capture devices and for removing animals from thosedevices. Pain or distress as described in the USDA/APHIS
Animal Care Policy Manual (USDA 2015a) is unlikely to result
from the simple capture of free-ranging mammals in most live
traps or capture devices. Thus, Category C is appropriate if
these activities occur as part of a project that includes USDAcovered species.
Most tissue sampling and marking techniques conductedin the field are also consistent with USDA Pain or Distress
Category C provided that these procedures are not more invasive than peripheral blood sampling. Support for this classification is provided in the Guidelines for Preparing USDA Annual
Reports and Assigning USDA Pain and Distress Categories.
This document is distributed by the NIH Office of Animal Care

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who is responsible for obtaining permits and keeping associated records. Where permits are required, work cannot be conducted legally until the necessary documents have been secured.
Although some institutions require permits before an IACUC
protocol can be approved or even reviewed, this approach typically increases the workload of both the PI and the IACUC
because permit renewal dates rarely coincide with protocol
dates. Further, permits are issued to the individual PI rather than
to the institution. Thus, a prudent approach is to approve acceptable protocols but specify to the investigator in writing that work
cannot commence until all required permits are in place.
Beyond meeting legal requirements, the issuance of permits
can provide assurance to the IACUC that any impact of proposed activities on local populations is minimal or is scientifically justified. Whereas IACUCs seldom have the expertise ordata necessary to make such judgments, permitting agencies
are usually charged with safeguarding these natural resources
and have personnel with the appropriate expertise to makeinformed decisions as part of permit application review andapproval. Thus, attention to this major difference between biomedical and wildlife research can be accomplished without
additional burden on the IACUC.

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2.31 “animal areas containing free-living wild animals in theirnatural habitat.” How the definition of field study corresponds
to the USDA reporting categories is unclear. In most instances,
protocols involving only procedures classified as Category C
are consistent with the regulatory definition of a field study, butwhether these should be included on annual reports has been
uncertain. The USDA provides relevant guidance in their 2015
revision of the Animal Welfare Inspection Guide (USDA 2015b)(the guidance document issued to Veterinary Medical Officers
charged with inspecting registered institutions) by stating that“animals euthanized, killed, or trapped, and collected, such as
for study or museum samples, from their natural habitat via
humane euthanasia” should not be included on annual reports
to the USDA. Unfortunately, the wording of this document,
although not regulatory in the strict sense, could be construed
to mean that animals captured, whether euthanized in the fieldor not, fall under the field studies exclusion and are therefore
exempt from IACUC review. The ASM states emphatically thatany activity involving the capture of wild mammals should be
subject to review by an IACUC to determine whether the activity meets the regulatory definition of a field study and, if not
found to be exempt, to provide appropriate oversight for use ofwild mammals in research.
With regard to IACUC protocol review, the PHS Policy on
Humane Care and Use of Laboratory Animals makes no distinction between laboratory and field studies. Guidance fromthe NIH/OLAW (FAQ A6) states, “[i]f the activities are PHSsupported and involve vertebrate animals, then the IACUC
is responsible for oversight in accordance with PHS policy.
IACUCs must know where field studies will be located, what
procedures will be involved, and be sufficiently familiar with
the nature of the habitat to assess the potential impact on the
animal subjects. Studies with the potential to impact the healthor safety of personnel or the animal’s environment may need
IACUC oversight, even if described as purely observationalor behavioral. When capture, handling, confinement, transportation, anesthesia, euthanasia, or invasive procedures are
involved, the IACUC must ensure that proposed studies are inaccord with the Guide.”Protocols and protocol forms for wildlife studies
Even with standards and guidelines appropriate for wild animals, activities must be described in sufficient detail to permit
critical review by oversight bodies. This can best be accomplished by use of protocol forms designed to address concerns
relevant to the circumstances and specifics of field work withwild animals. For example, protocols for work with wildlife
must describe how animals are captured for study, discuss thepotential for capture and the subsequent disposition of nontarget species, and address the uncertainty that often exists regarding the number and sex of animals that might be taken in any
trapping or capture event. Other differences include the factthat some wild mammals can be handled only after chemical
immobilization and that veterinary care is seldom possible in thefield for animals injured during capture or manipulation. These
are among the multiple wildlife-specific concerns that must be

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and Use, which is the oversight office for intramural research.
This guidance expressly states that Category C includes mostblood collection procedures and tissue collection proceduresthat involve no or only momentary or slight pain. Based onthese same NIH Guidelines, USDA Category C is appropriate
also in instances where procedures requiring peripheral tissue sampling or tagging and subsequent release of free-ranging animals necessitate chemical immobilization to conduct
the procedures, provided that immobilization is performed
only to facilitate the procedure and protect the animal and theresearcher from injury rather than to alleviate pain or distressinduced by the procedure.
Capture of free-ranging mammals in properly functioning
kill traps typically meets the USDA Category C. The same istrue of those animals captured in live traps, even if they are subsequently euthanized as part of the research study. The methodand quality of death is the criterion for classification. Any
method recognized as an approved method of euthanasia by
the AVMA is consistent with Category C. Because neither the
AWA nor its implementing regulations reference the AVMA’s
Guidelines for the Euthanasia of Animals, for those methods
not approved by the AVMA for euthanasia, the IACUC is thedeciding body as to whether the method of death meets theregulatory definition of euthanasia as defined by the AWA.
Additional information on kill traps and methods of death pertinent to USDA reporting is provided in the section of the AVMA
guidelines entitled Euthanasia and Humane Killing.
Euthanasia and humane killing.—Even for trapping methods that ordinarily are consistent with Category C, in the eventof a problem in the field not associated with experimental
manipulations that results in pain or suffering and necessitates
pain alleviation, post hoc classification as Category D would
be appropriate for that particular animal. For example, if either
a live or a kill trap malfunctions, leaving an animal in pain or
distress and the animal is either treated with appropriate pharmaceuticals or euthanized in a timely fashion, then Category
D is the most appropriate category. In the case of euthanasia,
this procedure (rather than treatment) is used to alleviate pain
or distress. It is important to note that these cases can occasionally occur with wild animals despite the trapping techniques
ordinarily being consistent with Category C. The foregoing is
not meant to imply that a higher level of pain or distress should
be expected in proposed activities, but simply that PIs and
IACUCs should be cognizant of the need to reclassify animals
on a post hoc basis should actual events warrant.
Field studies.—Considerable misunderstanding has surrounded the application of the AWA to field research.
Regulations promulgated by the USDA under the AWA exempt
field studies from IACUC review [9 CFR 2.31(d)] in cases inwhich field study is defined as “any study conducted on freeliving wild animals in their natural habitat that does not harmor materially alter the behavior of the animal under study” (9CFR 1.1). None of these terms is defined in the regulation or
in guidance documents issued by USDA/APHIS, which leaves
the IACUC responsible for their interpretation. The same
regulation exempts from the inspection requirement of 9 CFR

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

considered by IACUCs for responsible oversight of activities
involving wild animals, but, as noted above, protocol forms
designed for biomedical research seldom address these issues.
A wildlife-specific protocol form developed collaboratively by
the ASM ACUC and the Ornithological Council was featured
in a webinar sponsored by NIH/OLAW. A revision of this form
is freely available on the ASM website (http://mammalogy.org/
uploads/committee_files/ModelWildlifeProtocol2016.docx).

if not entirely domesticated, have been maintained in captivity
for sufficient time to habituate to interactions with humans. The
vast majority of biomedical research is accomplished with only
2 species of mammals—laboratory rats (Rattus norvegicus) andmice (Mus musculus). In addition to the wild counterparts ofthese 2 domesticated rodents, there exist more than 5,400 species of mammals that field investigators might study scientifically (Wilson and Reeder 2005). For such research, the IACUC
will require a protocol in which the investigator provides anadequate description of the study methods, experimental design,and expected results, as well as a summary of related, previous
studies. The IACUC might query investigators about planned
methods of euthanasia even if the proposed study involves only
observation or capture and release of animals. “We are not killing any animals” is a frequent, but unsatisfactory, response to
an IACUC because it indicates that the investigator has notconsidered methods of treatment or euthanasia in the event ofan unexpected injury. Importantly, it is usually appropriate forfield protocols to list a variety of euthanasia methods to suit the
species and conditions encountered.
Because most capture methods for free-ranging mammals
are not species specific, it is important for PIs to include, and
IACUCs to accept, considerable latitude in the list of target andnontarget species that might be encountered. Species lists thatare too narrow can place a PI out of compliance if unexpected
captures are made. These unexpected captures often provide
particularly important distributional records for species notknown to occur in the study area and might even represent
previously unidentified species. In some instances, it might beappropriate for species lists to include statements like “all small
mammals occurring in the region.”
The investigator should provide assurance to the IACUC thatall permits necessary for the proposed use of wild mammals
have been issued or requested; copies of permits must be available if requested by the IACUC. Although most IACUCs usually do not focus on scientific merit, Principle II of the UnitedStates Government Principles for the Utilization and Care of
Vertebrate Animals Used in Testing, Research, and Training
states that “procedures involving animals should be designed
and performed with due consideration of their relevance tohuman or animal health, the advancement of knowledge, or thegood of society.” IACUCs that deal primarily with biomedical protocols sometimes have difficulty evaluating the meritof field study protocols. Peer review of scientific proposals,
approval of project permits by state or federal agencies, andsupport from academic departmental chairs can provide assurance to the IACUC that the project is sound and the use ofanimals justified. Although rare, the IACUC might seek an outside assessment or request evidence of peer review to evaluatescientific merit.
In concluding this overview, we emphasize that this document is not intended to be an exhaustive catalog of procedures
and requirements; we encourage investigators to consult with
their IACUCs during protocol preparation to insure that alloversight concerns are addressed. We also emphasize that final
approval of any protocol rests with the IACUC.

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Numbers and species (including endangered taxa)
The Guide (NRC 2011) requires that protocols include details
concerning the numbers of animals to be used. These details
are relevant during IACUC discussions of the “3 Rs” outlinedin the Guide (Reduction, Refinement, and Replacement—NRC
2011) and direct IACUC members to determine if the fewest animals necessary to accomplish the stated research goals
with statistical rigor are being used. Further, oversight agencies such as the USDA focus on appropriate association ofanimal numbers with procedures or research aims. Frequently,
field researchers do not know how many individuals will beneeded or sampled; this is particularly true for faunal surveys
or other exploratory work common in mammalogy. While animal captures obviously vary with density and environmental
conditions, statements in protocols such as, “it is unknown how
many animals we will capture” are generally not well received
by the IACUC. Although inclusion of statements like, “20 individuals from each species for each locality,” is one way to provide numerical limits, a stronger approach is to consider more
acceptable generalized statements such as: “In this survey we
expect to collect different species of Oryzomys and will sample
an estimated 25 localities. We will not exceed 20 specimens
per species of Oryzomys per locality. It is anticipated that the
total number of specimens collected during this study will not
exceed 500 individuals per year.”
The numbers of animals required in field studies will vary
greatly depending on study design, species’ life history characteristics, and the research questions posed. Behavioral studies
might involve capture of only a few animals in which the focus
is a specific activity, or capture of an entire population in which
all individuals must be marked. In the latter case, the investigator can provide a statement that “all animals in the population will be captured, marked, and released, and it is estimatedthat this will not exceed 200 individuals per year.” Genetic,taxonomic, ecological, and other studies typically require aminimum sample size for statistical analyses. Too few animals
might not allow the investigator to address research questions
with sufficient scientific rigor and, subsequently, will result ina waste of animals if the results do not provide a robust test of
the relevant hypothesis. In these situations, a power analysis
might be performed to estimate the number of animals required
to obtain statistical significance for a given variance and a minimum expected difference between samples.
IACUCs also are charged with approving the particular species of mammals involved in a project. Biomedical protocols
typically use strains of animals that have been domesticated or,

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General Guidelines

Training
Training, especially in the rapidly changing area of researchcompliance, is extremely important for all individuals handlingvertebrate animals. Online training is often required by the
IACUC as part of protocol review and approval. Frequently,
though, this training is general and oriented toward laboratory environments. The Collaborative Institutional Training
Initiative (CITIprogram.org) used by many institutions includes
an informative wildlife-specific course in addition to generaltraining in animal use. NIH/OLAW sponsors freely available
webinars on animal research topics and at least 1 of these has
focused on oversight of wildlife research. These resources areavailable through the NIH/OLAW education portal at http://
grants.nih.gov/grants/olaw/educational_resources.htm. Other
wildlife-focused webinars or podcasts have been made available by Public Responsibility in Medicine and Research(PRIM&R) and AAALAC International.
Still other training opportunities are organized by local
IACUCs and tailored for their institutions. Procedural training
can be provided by veterinarians or technicians experienced
in research-oriented procedures. Specialized training can provide the investigator with experience in acceptable methodsof restraining, marking, monitoring vital signs, administering
injections, taking blood samples, and assessing stress or signsof pain or distress. The investigator is responsible for knowing how to perform procedures in the appropriate setting (field,
laboratory, etc.) for which their protocol was approved.
The IACUCs are urged to recognize the investigator as acollaborator who is sometimes well versed in the biology of
the taxa studied. Wild vertebrates, particularly mammals, arevastly different in physiology and behavior from the usuallyhighly inbred organisms used in biomedical research (Sikes
and Bryan 2015). Wild vertebrates do not inhabit antiseptic,

Oversight of field studies
Although field studies as defined by the AWA (those conducted on free-living animals in their natural habitat that do not
involve invasive procedures, harm, or materially alter behaviorof an animal) are exempt from IACUC review [9 CFR 2.31(d)], many institutions interpret the AWA in a broader sense
and require IACUC review of all laboratory, classroom, andfieldwork involving vertebrates. For those studies that require
review and approval by the IACUC, many references for common field procedures for mammals are available (e.g., Kunz andParsons 2009; Martin et al. 2011; Ryan 2011); these sources
should be consulted by the investigator during protocol preparation and referenced as needed. Further, some institutions may
have standard procedure descriptions available for use by all
investigators preparing protocols.

Trapping Techniques
Considerations for capturing mammals
Although capture of wild mammals is a common element offield studies, physical capture is not always necessary andinvestigators can sometimes use other procedures to monitor
free-living animals. These include obtaining acoustic signatures (ultrasonic detectors), visual data (still or video cameras),
or nondestructive tissue samples (sticky hair snares to removehair) from free-ranging mammals without substantially altering
the animals’ behavior. In general, these techniques are not ofconcern to IACUCs unless they involve capture (e.g., capturingbats in mist nets to identify species before animals are released
and their vocalizations recorded as they retreat), harassment, orvisiting nest sites during critical times in a species’ life cycle(e.g., bat nursery roost or seal pup nursery). Concerns may also
exist that the investigator’s presence can alter animal behavior
or place animals or personnel at risk for exposure to pathogens
or other harm (Klailova et al. 2010). Individual IACUCs andinstitutional policies vary widely regarding exemptions forobservational studies and thus investigators should become
familiar with their institutional policies before beginning any
work with mammals.
Common reasons to capture mammals include livetrappingto tag (with radiotransmitters, necklaces, ear tags, or passive integrated transponder [PIT] tags), mark (number, band,
hair color, freeze brand, ear tag, or toe clip), or collect tissue.
Regardless of approach, the potential for pain, distress, or suffering must be considered. A variety of methods and devices
are available for trapping wild mammals. Techniques for capture of specific species of mammals are detailed in summary
sources (Wilson et al. 1996), internet sites devoted to specificsubsets of mammals (e.g., http://www.fishwildlife.org/index.

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Fieldwork with mammals
Fieldwork is arguably the most challenging form of research
for IACUCs and others who typically evaluate use of animals
in laboratory-based studies. Fieldwork in mammalogy involves
designing and conducting research to address scientific questions while working with mammals in their natural habitats.
This process might involve capturing an animal to obtain reproductive and other data and subsequently releasing it to obtain
additional information on population dynamics, movements,and habitat relationships. In some cases, the investigator mightbring a wild-caught animal into an animal facility for further
study. These wild animals might require sedation or anesthesia to facilitate handling, but use of suitable pharmaceuticals
is often under federal and state control, so investigators should
consult with federal and state drug enforcement agencies andobtain appropriate licenses during the design stage of a study
if their use is anticipated. Some drugs (e.g., narcotics) require
strict inventory logs and storage in doubly locked areas to prevent unauthorized access, requirements that can be challenging
to meet in the context of field work.

stress-free environments with ad libitum food. With these differences in mind, investigators should serve as resources totheir IACUCs and institutional veterinarians and all of these
individuals should work together to insure the appropriate useof animals in research.

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

php?section=furbearer_management&activator=27 for furbearers), and especially in articles from the primary literature.
Possibilities include live traps (e.g., Sherman, box, mist nets,
snares, Tomahawk, Havahart, pitfall, nest box, and artificial
burrow), kill traps (e.g., Museum Special, Conibear, and pitfalls), and other specialty traps for particular species or purposes. Shooting with a firearm might be necessary to obtainspecimens of some species. We address each of these generalcategories of traps in greater detail below.

staking or visibly flagging a trap line (or otherwise devisingsome effective system) to ensure that all traps are recovered andremoved reliably and efficiently. Regular monitoring ensuresthat target animals remain in good condition while in traps andallows prompt release of nontarget species with no ill effects
due to capture. Monitoring intervals vary and are dependent
on target species, type of trap, weather, season, terrain, andnumber and experience of investigators. Generally, live traps
for nocturnal species are set before dusk and checked shortly
after sunrise. Traps are then retrieved or closed during the day,where warranted, to prevent capture of diurnal, nontarget taxa.
Live traps for very small mammals, particularly shrews, should
be checked more frequently (e.g., every 1.5 h—Hawes 1977)
to minimize mortality due to the higher metabolism of thesetaxa. Similarly, taxa of larger size but with particularly highmetabolic rates (e.g., Mustela) might also require shorter intervals between observations. Live traps for diurnal species should
be set in shaded areas or under trap shelters (Kaufman and
Kaufman 1989) and checked every few hours in warm weather.
Traps should then be retrieved or closed at dusk, when appropriate, to prevent unintended capture of nocturnal taxa.
Thermoregulatory demands, especially for small mammals,
can induce stress even if the duration of captivity is short.
Thermoregulatory stress can be minimized by providing foodsources (Do et al. 2013) and nesting material in the live trap.
Because most live traps for small mammals are constructed ofmetal and conduct heat readily, it might be necessary to insulate
traps to minimize hypo- or hyperthermia in captive animals.
Insulation can be accomplished by using items such as cottonor synthetic fiber batting, leaves, or twigs to provide dead air
space between the animal and conducting surface and to provide
escape from the temperature extremes. Critical temperature tolerance limits vary with species and environmental conditions.
Investigators must be responsive to changing weather conditions and modify trapping procedures as necessary to minimize
thermal stress to trapped animals.
If disturbance of live traps (removal of captured individual,
trap damage) by larger carnivores, birds, or other animals is
problematic, trap enclosures (Getz and Batzli 1974; Layne
1987) or other methods to secure traps might be required.
Pitfall traps can be fitted with raised covers to minimize captureof nontarget species, to provide cover from rain and sun, and toprevent predation by larger animals. Pitfall traps used for live
capture may require small holes at the bottom of the containers to allow drainage in rainy weather, or enhancements suchas small sections of polyvinyl chloride pipe to provide shelter
from other captured animals.
Captured small- and medium-sized mammals should be
handled by methods that control body movements without
restricting breathing. Covering an animal’s eyes may reduce
struggle to escape. Restraint by a mesh or cloth bag allows theinvestigator to mark, measure, or otherwise sample an individual through mesh or the partially opened end of the bag (e.g.,
Cynomys gunnisoni—Davidson et al. 1999). Some small mammals can be transferred directly from a trap to a heavy-duty
plastic bag for handling or to a heavy cloth bag or cage for

Downloaded from http://jmammal.oxfordjournals.org/ by guest on June 10, 2016Live capture
Investigators conducting research requiring live capture of
mammals assume the responsibility for using humane methods that respect target and nontarget species. Methods for live
capture include those designed for small mammals (Sherman,
Tomahawk, and Havahart traps, pitfalls, artificial burrows, andnest boxes), medium-sized to large mammals (Tomahawk,
Havahart, and foot-hold traps, snares, corrals, cannon nets, culvert traps, and darting), bats (mist nets, harp traps, and bags),
and fossorial mammals (Baker and Williams 1972; Hart 1973).
Methods of live capture should not injure or cause excessive stress to the animal. Adequate measures should be taken
to ensure that captured animals are protected from predationand temperature extremes and have food and water available,
as needed, while restrained in traps. For permanent trapping
grids or webs, the investigator might provide shelters over traps
to protect captured animals from environmental conditions(Kaufman and Kaufman 1989; Parmenter et al. 2003).
Use of steel foot-hold traps for live capture of animals
must be employed with caution due to the potential for injury
or capture of nontarget species (Kuehn et al. 1986). For
some taxa, foot-hold traps, including leg snares, might present the only available or the most effective means of capture(Schmintz 2005; see also http://www.fishwildlife.org/index.
php?section=furbearer_management&activator=27 for specific techniques and trap recommendations). When their use isapproved, investigators have an ethical obligation to use steel
foot-hold traps of a sufficient size and strength to hold theanimal firmly. Foot-hold traps, other than snares, with rubberpadded or offset jaws should be used to minimize potential
damage to bone and soft tissue and associated discomfort for
those cases in which animals will remain alive in these traps.
Snares or spring foot-hold traps must be checked at suitable frequencies. These observations should be at least daily, but might
be more frequent depending upon target species, the potential
for capture of nontarget species, and environmental conditions.
Captured animals must be assessed carefully for injury andeuthanized when necessary. Nontarget species, if uninjured,
should be released immediately although their release, as withtarget species, might require chemical immobilization to facilitate handling and prevent injury to the animal or researcher.
The number of traps set at a particular time and location
should not exceed the ability of the investigator(s) to monitor them at reasonable intervals. Because frequent checking oftraps is the most effective means of minimizing mortality or
injury to animals in live traps, the investigator should consider

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active. Captured bats should be removed from nets immediately
to minimize injury, drowning, strangulation, or stress. Properand thorough training of assistants beforehand is essential sothat bats are removed without injury to delicate wing bones andpatagia. If a bat is badly tangled, it can be removed by cutting
strands of the net; although costly, mist nets can be repaired or
replaced. Nets should not be operated in high winds because
these conditions can place undue stress on bats and further
entangle them in nets. Mist nets should generally be operated
only at night or during crepuscular periods and closed during
the daytime to prevent capture of nontarget taxa (e.g., birds).
The number of mist nets operated simultaneously should notexceed the ability of investigators to check and clear nets ofbats. For example, mist nets should not be used where large
numbers of bats might be captured simultaneously (e.g., at caveentrances) because numbers can quickly overwhelm the abilityof investigators to remove individuals efficiently and safely. In
these situations, harp traps or sweep nets are preferable (Wilson
et al. 1996). Although harp traps do not require constant attention, they should be checked regularly, especially when a large
number of captures is expected within a short period of time.
Investigators using harp traps should guard against predators
entering the trap bag or biting captured bats, predation of 1 bat
species on another, rabies transfer, or suffocation due to large
numbers of bats caught in a short time (Kunz and Parsons 2009).
Roosting bats can sometimes be captured by hand. The useof suitable gloves should be considered as they provide protection from bites while allowing the investigator to feel the
body and movements of the bat, thereby preventing injury toboth the investigator and the study subject. Long, padded tissue
forceps can be used to extract bats from crevices, but extreme
care should be taken to avoid injury to delicate wing bones andmembranes (Kunz and Parsons 2009). Investigators should consider how the time of year when bats are studied might impact
their survival. For example, large or repeated disturbance ofmaternity colonies can cause mortality of offspring and colony
abandonment (O’Shea and Bogan 2003). Repeated arousal ofhibernating bats can lead to mortality because of depletion ofcritical fat stores (Thomas 1995). Individuals working withbats should also follow the most current precautions to prevent
spread of the fungus causing White Nose Syndrome (https://www.whitenosesyndrome.org/resource/universal-precautionsmanagement-bat-white-nose-syndrome-wns). Reeder et al.
(2015) is a particularly useful reference regarding the potential for spreading diseases while conducting research on at-risk
populations.
Capture myopathy and injuries
Wild mammals typically will experience some level of stressduring capture regardless of the capture technique employed.
For those methods that involve pursuit of the target animal, personnel must be especially cognizant of the potential for exertional rhabdomyolysis (ER or capture myopathy). The potential
for ER can be minimized by limiting pursuit times, restricting
captures to periods when environmental conditions minimize
the chance that an animal will overheat, carefully selecting

Downloaded from http://jmammal.oxfordjournals.org/ by guest on June 10, 2016transport. The design of some traps (e.g., box-type traps such as
Sherman or Tomahawk live traps) also allows them to be used
as a temporary cage for easy and safe transport.
Traps used for live capture of larger mammals include box
traps, clover traps, and culvert traps. Some large mammals (e.g.,
ungulates and kangaroos) can be herded along fences into corrals or captured with cannon nets or drop nets projected fromhelicopters using net guns. These methods require extensive
training of personnel and immediate attention to the animals toprevent injury while minimizing stress and distress in particularly sensitive species (e.g., Antilocapra americana). For suchlarge-scale capture efforts, it may be useful to contract a veterinarian to assist with any injured or stressed animals. Dependingon the nature of the activity, individuals captured using thesetechniques might need to be sedated, otherwise restrained, or
have their eyes covered until the investigator’s work is completed (Braun 2005).
Large mammals also can be captured by delivering a sedative
into the hip or shoulder musculature using a dart gun. Chemical
immobilization, whether for capture or sedation, requires training by a wildlife veterinarian and thorough knowledge of proper
dosage, antidote, and sedative effect. In many instances, having
a reversal agent on hand is advisable. The location selected fordart placement can vary seasonally and with animal condition.
Individuals familiar with the species should be consulted prior
to employing this procedure. An excellent reference for chemical immobilization of mammals is Kreeger and Arnemo (2012).
Location of the animal within the habitat should be consideredin light of time necessary for sedation and recovery to avoid
injury or mortality during recovery; sedated mammals must
be monitored closely during procedures. Baits laced with tranquilizers have been described (Braun 2005), but these should
be used with caution to prevent sedating nontarget species.
Finally, local, state, or federal regulations might restrict use ofcertain drugs (e.g., narcotics), which may impact their use infield settings.
In procedures with domesticated species, sedated animals
are always monitored until they recover. Similar monitoringof wild mammals might not be possible or appropriate. The
presence of humans is a stressor for most wild animals andthey will often attempt to flee before they are fully recovered.
Depending upon the species and habitat, it may be advisable toplace sedated animals in a safe location and then retreat, rather
than remaining in close proximity to individuals as they recover(Sikes and Bryan 2015). In no instance should sedated animals
be left in close proximity to water or exposed to potential predators or aggressive conspecifics while under the influence ofimmobilizing drugs.
Net-gunning from helicopters is a method frequently used
for capture of ungulates and at times for capture of othertypes of mammals. Depending upon the species and activities
involved, animals captured in nets may be sedated or they may
be handled without sedation.
Bats can be captured effectively and humanely with mist nets,
harp traps, bag traps, or by hand (Kunz and Parsons 2009). Mist
nets should not be left unattended for > 15 min when bats are

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

drugs used for immobilization, and ensuring the expertise of
the capture team. When pursuit is used for capture, the researchteam should monitor animal temperature and have materials on
hand to quickly reduce core temperature if necessary.
Wild mammals usually struggle or attempt to flee whenapproached by humans and can injure themselves as a result.
Excessive rates of injury warrant review of the animal handling procedures. Whereas minor injuries can often be treatedby the field personnel, severely injured animals typically are
humanely killed.

(2:1) added to the solution. Small mammals that fall into thetrap (and hence the drowning fluid) lose buoyancy almost
immediately due to the surfactant action of hexane and mineral
oil and thus submergence and death occur rapidly. Alcohol theninfuses the body and acts as a preservative. As long as the solution is deeper than the head-body length of the target animals,
individuals cannot struggle or escape by standing on the bottom of the trap. Use of formalin or ethylene glycol in pit traps,
however, is not approved by the ASM. Pitfalls used as kill traps
should have covers or other means of excluding nontarget species. If the traps will not be operational for extended periods,
they should be constructed such that the kill jar and its fluid canbe removed to prevent unwanted captures.
Drowning in conjunction with other trapping methods
Several of the methods described above include a primary capture device (trap) that induces death by drowning. While the
AVMA (2013a:102) does not consider drowning an acceptable form of euthanasia, it acknowledges that “the quickest
and most humane means of terminating the life of free-ranging
wildlife in a given situation may not always meet all criteria
established for euthanasia (i.e., distinguishes between euthanasia and methods that are more accurately characterized as
humane killing)” (AVMA 2013a, Section S7.6). Further, in a2011 “Literature Review” regarding thoracic compression, theAVMA states that “when scientifically justified, the IACUC has
and should employ the authority to approve killing techniques
not listed as recognized forms of euthanasia” (AVMA 2011).
The ASM urges the use of other trapping and killing techniques
whenever possible. However, wild mammals held in traps areunable to avoid predators or to forage, so in situations whereother trapping options are not feasible and capture limits ananimal’s ability to maintain itself (e.g., through continued foraging or defense against predators), the ASM considers deathby drowning to be more humane than alternatives that cause
prolonged distress or discomfort.
In all cases, investigators should strive to use the trap thatwill inflict the least trauma and result in a clean, effective kill.
Most traps should be checked at least once a day; in the eventthat a captured animal is still alive, it should be immediately
dispatched according to methods approved by the IACUC.
The AVMA offers these recommendations regarding kill traps:“Mechanical kill traps are used for the collection and killingof small, free-ranging mammals for commercial purposes (fur,skin, or meat), scientific purposes, to stop property damage,and to protect human safety. Their use remains controversial
and kill traps do not always render a rapid or stress-free death
consistent with the criteria established for euthanasia by the
POE. For this reason, use of live traps followed by other methods of euthanasia is preferred. There are a few situations whenthat is not possible (e.g., pest control) or when it may actually
be more stressful for the animals or dangerous for humans to
use live traps” (AVMA 2013a:40).
An effective way (sometimes the only way) to collect certain species of mammals is by use of a firearm. Investigators
using this method must be experienced in safe handling of

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Kill traps and shooting
Some studies require that free-living mammals intentionally bekilled (e.g., collection of specimens for museum collections). In
all cases, methods must provide an efficient and quick death thatminimizes pain. In some cases, individuals may be livetrapped
and then humanely killed. Where live traps are used, animals
should be humanely killed as quickly as possible (see methods
below) without damaging materials needed for research. The
AVMA notes that “kill traps do not consistently meet the POE’s[Panel of Euthanasia] criteria for euthanasia, and may be best
characterized as humane killing under some circumstances. At
the same time, it is recognized they can be practical and effective for scientific animal collection or pest control when used ina manner that ensures selectivity, a swift kill, and no damage tobody parts needed for field research” (AVMA 2013a:40).
Traps suitable for kill trapping include snap traps (e.g., Victor
and Museum Special) for rat- and mouse-sized mammals, killtraps (e.g., Macabee) designed for subterranean species, harpoon traps for moles, snares for carnivores and furbearers, andConibear or similar body-grip traps for medium-sized mammals. Trapping techniques that use drowning as a means of killing have been described as inhumane or unethical by some (e.g.,
Powell and Proulx 2003; AVMA 2013a). However, submersion
trapping systems can be effective and appropriate for furbearers
found in or near waterways. Such systems rely on equipment(e.g., steel foot-hold traps with 1-way cable slides and locks)
or techniques that cause the furbearer, upon capture, to quickly
and irreversibly submerge until death (http://www.fishwildlife.
org/index.php?section=furbearer_management&activator=27).
Pitfall kill traps can provide the best trapping option forsome small mammals (e.g., rodents and shrews), many ofwhich are much more effectively captured with pitfalls than byother means. These traps are particularly efficient where trapping must be continuous or cannot be accomplished using live
traps or snap traps that need resetting between captures. Pitfalls
used with drowning fluids add a measure of preservation thatcan be useful for scientific collections and detailed study ofinternal organs. Additional circumstances in which pitfalls are
effective are outlined in Beacham and Krebs (1980) and Garsd
and Howard (1981).
Ethical use of pitfall kill traps requires the minimization ofpain or distress. The pitfall designed by Howard and Brock(1961) does this by using 70% ethanol (or similar alcohol) as
the main ingredient of the drowning fluid. Evaporation of alcohol is retarded by a thin layer of light mineral oil and hexane

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Marine mammals
All marine mammals in United States territorial waters are covered by the Marine Mammal Protection Act of 1972. Many species also are covered by the Endangered Species Act of 1973.
The latest versions of both Acts can be found at the United States
Marine Mammal Commission web site (http://www.mmc.gov/
about-the-commission/our-mission/endangered-species-actand-other-legislation-and-agreements/). These Acts prohibit
any form of “take,” including terminal capture, live capture, or
tagging of marine mammals without appropriate federal permits. Exceptions are made for certain aboriginal or traditional
harvests of marine mammals and for commercial fisheries thatmight incidentally take marine mammals as part of normal fishing operations. Permit application forms and instructions canbe found on the National Marine Fisheries Service web site(http://www.nmfs.noaa.gov/prot_res/overview/permits.html)
and at the USFWS web site (http://permits.fws.gov/).
Methods of live capture for marine mammals include nets
(ranging from purse seines to small, handheld hoop nets) andmechanical clamps with lines that are placed over an animal’s peduncle while it rides the bow pressure wave of a vessel. Many live capture techniques for smaller cetaceans arereviewed by Asper (1975). Some dolphins or small whales (e.g.,
Phocoena, Delphinapterus) can be captured by hand in shallow water (Walker 1975). Although polar bears (Ursus maritimus) and some species of pinnipeds (e.g., northern elephantseal, Mirounga angustirostris) can be captured using remotely
injected chemicals, chemical immobilization of marine mammals is risky due to the possibility of losing animals by drowning or overdose (Dierauf and Gulland 2001). The Society for
Marine Mammalogy has developed detailed guidelines forthe treatment of marine mammals in field research, which the
ASM endorses. The most current version of these guidelines isavailable at. www.marinemammalscience.org/about-us/ethics/
marine-mammal-treatment-guidelines. Euthanasia for marine
mammals was reviewed by Greer et al. (2001).

Holding of marine mammals in captivity is regulated by the
Marine Mammal Protection Act, the Endangered Species Act,and the AWA; the latter administered by USDA/APHIS. The
AWA regulations include species-specific criteria for pool andpen sizes, construction methods, water quality, food storage
and handling, and routine healthcare. The most current AWA
regulations can be found on the USDA/APHIS web site.
Use of domestic dogs in researchHighly trained domestic dogs are increasingly being used inresearch to locate study animals or specimens. Because of theirolfactory abilities, these service animals can make many typesof collecting efforts more efficient and can allow types of fieldwork that are otherwise not feasible. Dogs used in this manner should be considered part of the research team rather thanstudy animals and should be accorded care as such. In cases inwhich dogs are owned by the institution, their veterinary care isequivalent to occupational health considerations for personnel.
When dogs are used to locate live animals, the potential
stress or harm they might cause to target individuals should beconsidered. For animals that alert handlers to the presence oftarget animals, the stress caused by the dog may be equivalent
to that caused by native predators or humans. When dogs areused to find samples (e.g., scats), there is less potential impact
on target animals as they may no longer be in the vicinity, but
nontarget animals may still be affected. Additionally, investigators and oversight personnel should take precautions to minimize the potential for exchange of pathogens between native
populations and service dogs. As the use of dogs in field studies
becomes more commonplace, more specific guidelines are sure
to follow.

Tissue Sampling and Identification
Tissue sampling
The collection of small amounts of tissue from small wild mammals is routine and often required for studies involving DNA,
proteins (e.g., hemoglobins, albumins, enzymes), or physiological assays (e.g., hormonal levels, antibody titers). Tissue
samples can be obtained in conjunction with some marking
procedures (e.g., toe clips, patagial, or ear biopsies). These
techniques are treated below under “External Marks.” Even
when these techniques are not required for identification, small
external tissue samples are frequently taken from unsedated
animals with little difficulty and are generally consistent with
USDA Pain or Distress Category C (see above). When blood isrequired, many procedures do not require anesthesia and canbe conducted in the field by appropriately trained personnel.
After tissue collection and prior to release, individuals should
be observed to ensure that no trauma or adverse reaction has
occurred as a consequence of capture, handling, or tissue or
blood collection.
Multiple factors must be considered when determining
the most appropriate method for obtaining blood samples.
Various morphological attributes of a species (e.g., size of theorbit, absence of tail or external pinnae, presence of cheek

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firearms and must adhere to laws and regulations related totheir possession and use. The firearm and ammunition should
be appropriate for the species of interest so that the animal iskilled swiftly without excessive damage to the body (including
the skull). A .17 or .22-caliber rifle chambered for an appropriate cartridge (.17 HMR, .22 Long Rifle, .22 Short, .223, etc.)
and loaded with bullets or shotguns loaded with appropriate
shot sizes are suitable for medium-sized mammals. Generally,small mammals (chipmunk size or smaller) can be taken with
.22-caliber rifle or handgun loaded with #11 or #12 (dust) shot,
whereas animals the size of rabbits can be taken with shotguns
loaded with #4–#6 shot. Large mammals should be taken witha high-velocity rifle of a suitable caliber, where legal, or shotguns using appropriate ammunition (e.g., rifled slugs or largershot). After the animal has been shot, it should be retrieved
and processed promptly for the purpose for which it was collected. Additional information regarding killing via gunshot
is provided in the section below on “Euthanasia and Humane
Killing.”

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

External marks
Individual identification of mammals is necessary formany types of studies, both in the laboratory and the field.
Identification marks can be natural (stripe pattern, color, ormane patterns) or can be applied by the investigator. Of primaryconcern is the distance from which the animal must be identified and the time period over which the mark must endure. It is
worth noting that marking techniques that do not permit identification at a distance or are not permanent might require repeat
trapping and handling of animals for reapplication of marks.
On large bodied species, natural variation in fur or whisker
patterns (West and Packer 2002) or marks left by previously
sustained injuries (e.g., scars on wings, ears, or flukes) often
suffice for permanent identification at a distance.
When appropriate naturally occurring marks are not available, external dyes, freeze brands, or paint marks might provide
the visibility and degree of longevity required. Identification
marks can be made with nontoxic hair dyes or paint. Careshould be taken to ensure that substances used for externalmarks are nontoxic and do not alter the behavior of animals or
subject them to increased predation (e.g., by adversely affecting the animal’s natural camouflage or increasing its visual or
olfactory detectability). Dye marks on juveniles or subadults

are of more limited duration because of rapid molting and thus
may require more frequent renewal. Freeze branding is aneffective means of marking bats and other species, and marks
might last several years (Sherwin et al. 2002). Tattooing and ear
punches provide a more persistent means of identification but
require handling of animals for individual recognition and may
not be permanent in some species.
Metallic or plastic tags and bands or collars may be suitable for identification at appreciable distances on large terrestrial species. Tags typically are applied to the ears of terrestrial
mammals and to flippers of seals and sea lions. Use of individually numbered tags on small mammals necessitates handlingthe animal each time an individual is to be identified. Although
they frequently are used with a high degree of success, eartags might inhibit grooming of ears and promote infection byparasites in some rodents (Ostfeld et al. 1996), although potential for infection likely varies with species and environment.
Further, unless carefully sized, tags might snag, either duringgrooming or when animals move through vegetation, resulting
in loss of the tag (Wood and Slade 1990). Eartags might also
affect typical movements of the pinnae (e.g., Preyer reflex) infree-ranging animals. Many of the problems associated with
ear tags are reduced in laboratory settings where such tags may
be especially useful for long-term identification. Ear tags may
not be an option for species with greatly reduced pinnae (e.g.,
many shrews). Wing bands for bats should be applied so thatthey slide freely along the forelimb, which may necessitate cutting a slit in the wing membrane in some cases. Another external marking option for bats is an appropriately sized bead-chain
necklace (Barclay and Bell 1988).
Individuals in some taxa can be identified by unique patternsof ear punches (where a small amount of tissue is removed fromexternal pinnae using a surgical hole punch). Ear punches, however, may become unidentifiable over time in free-ranging individuals because of healing, subsequent injuries sustained in thefield, or obscuration by hair. In some species, toe clips may be
used. Toe clipping involves removal of 1 or more digits or terminal
phalanges (generally only 1 per foot) and provides a permanent
identifying mark. Both ear punches and toe clipping typicallyrequire recapture as neither is generally suitable for identification
at a distance. Because both of these methods involve removal ofa small amount of tissue, they might be especially appropriate instudies where tissue samples also are required.
According to the Guide (NRC 2011:75), toe clipping “should
be used only when no other individual identification method is
feasible.” Justification for toe clipping of wild mammals should
include consideration of the natural history of the species, how
the feet are used in the animal’s environment, and the size ofthe toe. Digits generally should not be removed from the forefeet of subterranean or fossorial taxa because they are used for
digging, nor should primary digits be removed from arboreal
or scansorial taxa because they are used for climbing. Toe clipping in species with fleshy digits should be avoided. Toe clipping might be especially suitable for permanent identificationin small species (e.g., Chaetodipus, Perognathus, Peromyscus,
Reithrodontomys, and Sorex) and in neonates of larger taxa. Toe

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pouches) can limit potential sites of blood or tissue collection.
The size of the animal also might restrict collection sites andlimit the quantity of blood (≤ 1.5% of body mass) that canbe removed. The training and experience of the individuals
performing the procedure is important as unskilled personnel can cause significant trauma with some techniques. The
procedures for blood collection and the qualifications of study
personnel must be reviewed by the IACUC. More specialized
procedures for blood collection from small mammals are as
follows:
Obtaining blood from the facial vein.—This technique,which has been used on laboratory mice for many years, allows
collection of 4–10 drops of blood with minimal discomfort tothe animal (see USDA news release at www.ars.usda.gov/is/
pr/2005/050921.htm). The procedure is described (including
text, photos, and video) at http://www.medipoint.com/html/rat_
video_demonstraton.html (note: this citation is not intended to
be an endorsement of this commercial product by the ASM).
Obtaining blood from the caudal vein.—Extracting bloodfrom the caudal vein is a relatively simple procedure thatinvolves the use of a needle (more difficult in small rodents) orlancet to puncture the caudal vein. Alternatively, excising the
distal 1–2 mm of the tail can yield a small amount of blood; thetail tip can be used for DNA extraction.
Obtaining blood from the retro–orbital sinus.—Retro–orbital
bleeding should be used when less invasive blood collection
methods have been determined to be unsuitable. To minimize
the chances of damage to the eye, this technique should be performed by trained and experienced individuals. The use of very
short-acting anesthesia (e.g., isoflurane or sevoflurane) in aplastic bag will immobilize rodents in 15–20 s, thereby making
the procedure safer for the rodent and the handler.

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PIT tags are electronic devices encased in glass or resin capsules. They do not emit constant signals but can be interpretedwith a remote reader in much the same way that barcodes arescanned. PIT tags are becoming progressively smaller but canstill be too large for some species or individuals; their use invery small individuals should be approached cautiously. Tags
are injected subcutaneously using a modified large-bore hypodermic syringe and are suitable for many field and laboratory
identification needs. Tags should be massaged away fromthe point of insertion subdermally to prevent loss and allow

healing at the point of entry. Currently available PIT tag readers must be held in reasonably close proximity to the tag (~10 cm) to function and thus their use with large, aggressive
taxa (e.g., Procyon and Lynx) will usually require anesthesia
both for application and for subsequent reading of the tag toprevent injury to the animal and investigators. Because of theresultant stress for both subject and investigator, other methods of tagging large mammals, such as using radiotransmittersor naturally occurring markings, may be preferable. Ingestionof colored plastic particles or radioactive isotopes (such asP32) in bait can be used to mark feces for studies of movements of individuals or groups of individuals, although thismethod is of limited use for uniquely marking a large numberof individuals.
Chemical immobilization for application ofmarks and tissue sampling
Depending on the biology of the target species, its body size, andthe goals of the study, captured animals might require chemical
immobilization for safe and effective handling. Investigators
should consider that stress and restraint associated with immobilization might be greater than applying or reading a particularmark or taking noninvasive tissue samples without immobilization. Whether immobilization is required must be consideredon a case-by-case basis. If pain is slight or momentary and theanimal can be handled without unreasonable risk of self-injury
or injury to personnel, anesthesia might be contraindicated sothat the animal can be released immediately. Procedures thatcan cause more than momentary or slight pain or distress or
species in which the struggling animal is a danger to itself or
personnel should be performed with appropriate sedation, analgesia, or anesthesia (Interagency Research Animal Committee[IRAC] 1985:V). In these instances, field-portable anesthetic
machines allow use of isoflurane and similar inhalants to provide a reliable anesthetic and rapid recovery after the animal is
no longer exposed to the gas. Use of anesthesia for blood sampling will depend on collection procedure and species-specificconsiderations. Some anesthetics (e.g., ketamine) depress bloodpressure and make blood collection lengthier and potentially
dangerous. Anesthesia also might alter the blood component(e.g., cortisols) under investigation. Use of anesthesia should
be weighed against risk of mortality because some species arevery sensitive to anesthetics (e.g., felids—Bush 1995; Kreeger
and Arnemo 2012). Selection of anesthetics and analgesics
should be conducted in consultation with a specialist—suchas a wildlife veterinarian—knowledgeable regarding the useof these substances in species of mammals other than standard
laboratory or companion taxa. The investigator should conduct
a literature review to search for alternatives as well as for anesthetics and analgesics used in closely related species (Kreeger
and Arnemo 2012). Physiological measurements required forexperimental purposes also can affect the choice of anesthesia.
Sedatives, anxiolytics, and neuromuscular blocking agents are
not analgesic or anesthetic and hence do not relieve pain; thesesubstances must be used in combination with a suitable anesthetic or analgesic (NRC 2011).

Downloaded from http://jmammal.oxfordjournals.org/ by guest on June 10, 2016clipping and ear punches should not be used for marking bats,which instead can be effectively marked with wing punches or
freeze brands. Toe clips and ear punches should be performed
with sharp, sterilized instruments. Anesthetics and analgesics
generally are not recommended as prolonged restraint of small
mammals to administer these substances and consumption of
the analgesic substances (e.g., creams) via licking likely cause
more stress and harm than conducting the procedure without
their use. A recent study in laboratory mice showed that toe
clipping as late as 17 days of age caused no microscopic reaction as late as 10 weeks of age and that the use of vapocoolant anesthetics caused more harmful effects than toe removal
without anesthetics (Paluch et al. 2014; but see Braden et al.
2015 regarding the use of vapocoolant anesthetics in general).
The adverse effects of additional handling for application ofanesthetics or analgesics with wild taxa are likely to be substantially greater than was observed by Paluch et al. (2014) withlaboratory mice.
Radiotransmitters provide a mechanism to monitor movements and survival of animals and, therefore, also serve to identify individuals. Transmitters can be attached externally withsurgical or skin glue or a collar, or implanted into the body
cavity. External attachment often can be accomplished in thefield (Rothmeyer et al. 2002; Munro et al. 2006), whereas moreinvasive implantation might require transport to a laboratory
where sterile conditions can be maintained during surgery.
Investigators using collars should take into account the possibility that an animal will grow or undergo seasonal changes
in neck circumference (e.g., male cervids); the devices usedshould be designed to accommodate such changes (Strathearn
et al. 1984). If external transmitters are attached using glue,
members of some species will groom each other excessively
to remove adhesive from their fur (Wilkinson and Bradbury1988). Surgical implantation and explantation and more invasive procedures, which should be performed by a veterinarianor individuals who have received specialized training, usually require a suitable recovery period before the animal canbe released. Before using radiotransmitters, an investigatorshould consider the weight of the transmitter relative to thebody mass of the target species or individual. Generally, thetransmitter should represent < 5–10% of the individual’s bodyweight (Wilson et al. 1996). As an alternative to radiotransmitters, light-emitting diodes or similar markers might be fastened
externally to some species for nocturnal observation.

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

Maintenance of Wild-Caught
Mammals in Captivity

Maintenance environments
When individuals of wild species are to be maintained in captivity for > 12 h, the caging or holding environment must be selected
carefully to accommodate species-specific requirements andto minimize stress. Cages or pens of an appropriate size andconstruction must adequately contain animals for their healthand safety and that of investigators and animal care personnel.
Because of the great variety of mammalian species that might bemaintained, no specific guidelines for cage materials or size arepossible, but considerations should be given to all aspects of theecology, physiology, and behavior of target species. Guidelines
developed for husbandry of domesticated species, including
the Guide (NRC 2011), are seldom appropriate for wild-caught
individuals and may constitute inappropriate or even inhumane
treatment. Because of their capture as free-ranging individuals,
nondomesticated species may perform better in larger cages orpens than those used for similarly sized domesticated species(Fowler 1995). Temperature, humidity, lighting, and noise levels also must be within appropriate limits. An excellent sourceof information on the specific needs of wild-caught species is
the ASM’s Mammalian Species series (https://mspecies.oxfordjournals.org). Additional valuable information usually can beobtained directly from investigators or animal care staff familiar
with a particular species. Investigators proposing to maintainwild-caught mammals in captivity are encouraged to contact
other researchers or institutions experienced with the taxa inquestion and to consult with the IACUC’s attending veterinarian before submitting a protocol. Investigators should realizethat housing requirements often will represent departures fromthe Guide (NRC 2011) or the PHS policy on use of laboratory
animals (NIH/OLAW 2015), even if optimum for the proper
maintenance of nondomesticated taxa; as a result, investigators
should be prepared to justify proposed maintenance requirements to the IACUC and the IACUC approve departures.
Careful selection of bedding materials and substrate is critical to meeting the needs of nondomesticated species. Materials
used should simulate as closely as possible the animal’s natural environment and structure. Such materials might include
sand or fine woodchips for desert species, soil and leaf litter forshrews and fossorial forms, and hay or straw for other speciesof rodents. The quantity of bedding also might be important if
a dense covering (e.g., straw) allows establishment of refuges
or runways that are components of the natural environment of
the target species. More generally, some form of refuge should
be provided in which captive individuals can remain concealed
when possible because their availability influences behavior(Rusak and Zucker 1975).
Olfactory cues are a fundamental component of the naturalenvironment of most mammals, and the design of husbandry
practices should incorporate the maintenance of familiar scentsto maximize animal comfort. Individuals frequently scent markto establish territory boundaries and ownership. Frequent bedding changes and cage washing eliminates normal scent cuesand places captive individuals in a novel and potentially stressful environment. Investigators can reduce stress that accompanies cleaning by changing bedding and cage equipment on aless frequent cycle than typically used for domesticated species(often 1 or 2 times weekly for laboratory rodents). Additionally,
investigators can mix a small amount of old bedding with fresh
bedding. Species adapted to arid conditions (e.g., Onychomys)

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Procurement and holding conditions
When wild-caught individuals are to be held for an extended
period or transported, the investigator must provide a securemeans of containment, sufficient food and moisture, andappropriate ambient conditions and must consider the potential for transfer of parasites or pathogens, and the safety of theinvestigator(s) (see section on “Human Safety”). Cages must be
constructed to minimize possibility of injury or escape, to provide adequate ventilation, to allow for protection from wastes;
cages generally should be of sufficient size to permit the captive individual to make appropriate postural adjustments (NRC
2011, 9 CFR 3.125). Some types of live traps (e.g., Sherman
traps and Tomahawk traps) can be used as holding or transport
cages for short periods of time for appropriate species.
Captive mammals held for an extended period (> 12 h for
USDA-regulated species, which includes all wild mammals in
the United States) must be provided with suitable sources offood and moisture. Food can be provided at the time of capture. For many small mammals, especially rodents, fruits orvegetables (e.g., grapes, celery, cabbage, lettuce, or slices ofapple or potato) with high moisture content will suffice during transport or short periods of captivity until more permanent
housing, food, and water can be provided. Water bottles should
generally be avoided during transport because they will leakand dampen bedding.
Care must be taken when transporting captive animals toprevent their exposure to temperature extremes or precipitation, to provide adequate ventilation, and to minimize stress.
Regardless of cage construction, minimizing disturbance isbest. This may include placing transport cages in cool, darkened settings and minimizing noise and movement. In someinstances, these conditions can be achieved simply by placing adrape over the cage, provided air flow is sufficient and temperatures are not extreme.
Free-ranging mammals may carry diseases and almost certainly harbor ecto- and endoparasites. Some IACUCs require
treatment for ectoparasites before transport, and most will
require quarantine of newly captured individuals before entering an animal care facility. Even if these precautions are notrequired, the investigator should take appropriate steps tominimize potential impacts to other captive animals and tohumans. Most ectoparasites can be controlled by dusting withcommercial flea and tick powder. Treatments for endoparasites
are more involved and generally should be pursued after consultation with a veterinarian. Investigators should contact the
local institutional occupational health office for information onrisks to humans from species of mammals under consideration
before transport, housing, or maintenance.

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Environmental enrichment
Because the lack of stimulation in a captive environment can
result in development of stereotypic behaviors that confoundresearch interests, environmental enrichment can be a critical component of husbandry for nondomesticated mammals.
Enrichment might be as simple as increasing structural complexity in the cage or providing additional materials for manipulation. For example, the captive environment of woodrats(Neotoma) kept in false-bottom cages can be improved by providing rodent chow directly in the cage rather than in a feeder
attached to the cage front. This allows these natural hoarders toregularly rearrange food within their cage. Their environment
can be further enhanced by providing strips of cardboard thatwill simulate the woody debris these animals use to constructnests in the wild. Other species of rodents also can benefit from
inclusion of fibrous materials from which to construct nests.
Chipmunks (Neotamias) and red squirrels (Tamiasciurus) arevery active and can be difficult to maintain in captivity, but they
can be housed successfully by using cages that incorporate
3-dimensional structures (e.g., hanging branches and perches)along with a cage floor sufficient for digging and caching food.
For some species, hiding food in cardboard boxes allows theanimal to “forage,” thereby providing an important form ofenrichment.
The social structure of the target species also must be taken
into account when housing captive mammals. Captive situations
that permit an approximation of the natural social structure of

the target species are likely to be most successful and minimize
stress. Individuals of species that are social or gregarious should
be housed with other individuals when possible, but care must
be taken to ensure compatibility. Of course, investigators must
be aware of seasonal changes in social structure and modify
housing environments accordingly to minimize stress and control reproduction.
Captive housing of bats
Housing and caring for bats in captivity presents several particular challenges for investigators and IACUCs. Animal care programs should be designed in consultation with rehabilitation orzoo experts or other researchers experienced with the care of
the type of bats to be held (e.g., husbandry of fruit bats versus
insectivorous bats will differ substantially). To the extent possible, housing conditions should imitate wild conditions. For nonhibernating species or for hibernating species housed during theactive season, a flight cage that allows for and encourages freeflight should be provided. Obstacles such has hanging chainsor hanging dividers require maneuverability during flight (theappropriateness of which varies by bat species), which should
maintain natural behaviors and help prevent obesity, a frequent
occurrence in captive conditions. Multiple roosting pouches, aswell as numerous food and water dishes are preferable, so as
to minimize competition when individuals are housed together.
A flight cage should have double-wired walls to prevent escape.
The external wire should be sturdy, such as hardware cloth. Theinternal wire will vary by species (depending upon body size,
including size of the claws on hind feet), but window screen isoften selected. Excellent guidelines for the housing and care ofbats under captive conditions, including dietary considerations,can be found in Barnard (2011) and Lollar and Schmidt-French(1988).
For temperate, hibernating species, housing animals under
hibernation conditions is often required by the study design
or is otherwise desirable. Bats housed in modified refrigerators or in hibernation chambers require significantly less room
than active-season bats (bats can be placed in small cages;e.g., wire mesh (reptile) cages in which bats will roost on thesides). Hibernating animals must be maintained at temperaturesappropriate for the study species (determined by field data fromnatural hibernacula, which exist for many species) and requirevery high relative humidity (> 95%). These conditions (housing of flying animals in small cages, housing at very cold temperatures, and housing at very high relative humidity) deviate
from the “normal” limits for laboratory animals and may necessitate special approval from the IACUC. Animals captured in
the late fall or early winter and having sufficient body fat willenter hibernation in response to low ambient temperatures.
Hibernating bats must be provided with water using either
small trays or other waterers (e.g., chick waterers, which may
be filled from attached jars, with marbles placed into the bottom to prevent accidental drowning of torpid bats). Unless one
is studying a species that routinely feeds during the winter, theprovision of food is neither required nor desired. Hibernatingbats can be housed successfully under these conditions for

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will likely perform best when bedding changes occur every
10–14 days (or even less frequently), while others (e.g.,
Sigmodon) may require more frequent (e.g., weekly) changes.
Because scent marks often are deposited on watering devices
or cage lids, disturbance associated with being placed into anovel environment can be reduced by changing these devices
on a different schedule from that used for caging and bedding
so that individuals are not placed in an environment completely
devoid of familiar scents. The importance of establishing andmaintaining familiar surroundings, especially as identified byolfactory cues, cannot be overemphasized.
All species of mammals require some form of moisture in
captivity, although water sources and requirements vary widely
among species. Most mammals are best maintained with liquidwater provided in various containers or via lickable watering systems. However, some taxa, such as kangaroo rats (Dipodomys)
and pocket gophers (Thomomys), do not consume free water inthe wild because they obtain moisture directly from their foodand/or retain metabolic water (Boice 1972). These taxa can be
maintained in captivity by periodically feeding small amountsof moisture-containing produce such as cabbage, lettuce, celery, or apple. The frequency of these supplemental feedings isdependent upon the ambient humidity in the environment andthe water physiology of the species in question. If provided
with ad libitum access to free water, xeric-adapted species canbecome dependent upon these sources (Boice 1972), which can
result in changes in physiological functions that may confoundsome studies.

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

5–6 months (their normal period of hibernation). We strongly
recommend that researchers consult with other bat specialists who routinely house hibernating species, as the necessary environmental chambers are typically specially designed
and/or modified for bats. When housing hibernating animals,
including bats, disturbances must be kept to a minimum to prevent repeated arousal and the resultant exhaustion of energy
reserves. Hibernating animals should be checked remotely(using equipment that does not cause disturbance, including
sound at frequencies the animals can receive) or observed only
infrequently, often at greater than 2-week intervals.

Separation of taxa and minimizing stress
The Animal Welfare Regulations (9 CFR 3.133) state that animals housed in the same primary enclosure must be compatible.
That is, prey species should not be maintained near carnivores
and diverse taxa of carnivores generally should not be housed
together. Closely related species of some rodents frequently
co-occur in nature and often can be housed in the same room
without difficulty.
The general principles for identifying captive mammals in
pain or distress are abnormal appearance or behavior. Normal
appearances and behavior are determined by species-specificcharacteristics and personal experience of the handlers. Because
behavioral changes are the primary means for identifying pain
or distress, all personnel working with animals should understand the normal behavioral patterns of the species they are
housing. Thus, all animals should be monitored by trained staff.

Pain is generally easy to identify if it is associated with an
injury or physical abnormality, but stress or distress might not
be due to pain and thus not immediately recognizable. IACUCs
generally consider that procedures that cause pain or distressin humans likely also will cause pain or distress in other animals. Symptoms of pain in animals are species specific but
may include anorexia, rapid or labored respiration, immobility,
increased aggression, lack of grooming, periocular and nasal
porphyrin discharge, and abnormal appearance or posture (NRC
2008, 2009). An extensive list of indicators of pain for a varietyof laboratory animals is available from Cornell University at
https://www.iacuc.cornell.edu/documents/IACUC009.01.pdf,
but animal care personnel should be aware that wild mammals
often will provide little or no sign of pain or distress until thecondition is acute because overt signs of pain or distress would
be strongly selected against in nature, where predators or competitors may cue in to such signs.
Release of captive mammals
Release of wild-caught mammals that have been held in captivity might be justified in the case of 1) endangered or threatened species, 2) species of special concern due to population
dynamics, management needs, or conservation initiatives, or3) individuals held for only short periods of time. Research
designs that require release of captive animals as part of anexperimental manipulation must be planned to minimize bothpotential impacts on local population and stress to the released
individuals.
Concerns regarding release of individuals held in captivity formore than short periods include:• Introduction of individuals into an area without available
refuge and resources (especially problematic with highly
territorial species)• Alteration of population genetics• Introduction of individuals not acclimated to the local
environment• Introduction of pathogens acquired in captivity to wild
populations• Stress on local populations and released individuals• Excessive exposure to predation of released individuals
due to inappropriate foraging cycles (entrained by captive
light cycles or environments), extensive foraging due tonot having caches built up for winter months, or lack offamiliarity with local resources• Disruption of social systems• Lack of appropriate foraging skills (forgotten or neveracquired)• Legality of reintroduction of captive animals (varies withstate and country)
Decisions regarding release and permissible durations of captivity prior to release are often species- or project specific andmust be made on a case-by-case basis. Holding members of a
species for 1 or a few days to recover from surgical implantationof a transmitter or data logger is usually appropriate. In contrast,
release of highly territorial animals held for even short periods

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Observation intervals for captive wild mammals
Animals held in captivity will require routine care, which
includes food, water, and bedding changes as appropriate forthe species. Animal care guidelines and regulations also specify periodic observation to monitor the health and well-beingof individual animals. The Guide, for example, states (p. 112)that “[a]ll animals should be observed for signs of illness, injury,
or abnormal behavior by a person trained to recognize suchsigns. As a rule, such observations should occur at least daily,
but more frequent observations may be required, such as during
postoperative recovery, when animals are ill or have a physicaldeficit, or when animals are approaching a study endpoint.” Aswith the remainder of the Guide, these statements reflect standard husbandry practices for domesticated species and, in many
instances, will not be appropriate for wild animals held in captivity. There are no domesticated hibernators, for example, and adaily disturbance of hibernating mammals would quickly leadto death as energy reserves are depleted by repeated arousal.
Similarly, wild animals, particularly those recently brought into
captivity, will be stressed by regular close contact with humans.
In such instances, PIs and IACUCs must balance the disturbanceassociated with regular observations of nondomesticated animals against the information acquired from such monitoring. For
animals hibernated in captivity or animals housed in naturalistic
outdoor enclosures that permit foraging, observations may be
conducted less frequently or may be accomplished using indirect
signs such as disappearance of food and deposition of feces.

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into the same environment from which they were captured canbe problematic because vacant territories can be usurped suchthat reintroduction of a former resident virtually guarantees aconflict that would not have occurred had the resident not been
removed. For additional information regarding the potential
release of marine mammals, investigators are referred to thebest practices for these taxa developed by the National Marine
Fisheries Service (http://www.nmfs.noaa.gov/pr/pdfs/health/release_guidelines.pdf). Final disposition of captive animals isof concern, but the integrity of natural populations and humane
treatment of released individuals must be the highest priorities
in project design and IACUC deliberations.

Euthanasia and Humane Killing

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The Guide defines euthanasia as “the act of killing animals by
methods that induce rapid unconsciousness and death without
pain or distress” (NRC 2011:123). Euthanasia is often accomplished as a 2-step process that involves use of an agent todepress or eliminate central nervous function and a 2nd step
to stop the heart. The 1st action causes the animal to become
unconscious and insensitive to pain while the second is the actual
cause of mortality. Although both of these goals can be accomplished with a single agent, the primary concern is alleviating
pain immediately. Whatever the method, the objective is that the
animal feels no or only momentary pain, distress, or anxiety.
Euthanasia techniques are evaluated and approved by the
IACUC during review of the animal protocol. Investigators
should be aware that the Guide (NRC 2011) requires that methods of euthanasia be consistent with the AVMA Guidelines
on Euthanasia (AVMA 2013a) unless an exception is justified
for scientific or medical reasons. The AVMA distinguishes
between euthanasia and humane killing and notes that methods of killing other than those deemed “acceptable methods ofeuthanasia” might be justified in situations with free-ranging
wild animals. In the section on wildlife, the AVMA writes “thatthe quickest and most humane means of terminating the lifeof free-ranging wildlife in a given situation may not always
meet all criteria established for euthanasia (i.e., distinguishes
between euthanasia and methods that are more accurately characterized as humane killing)” (AVMA 2013a, Section S7.6).
Investigators and oversight personnel should realize that the
AVMA guidelines for euthanasia are a poor fit for many, if not
most, field settings, and thus often warrant IACUC-approved
departures from the Guide and the AVMA guidelines. The treatment of gunshot as a form of euthanasia or humane killing in the
AVMA guidelines is one such example. The AVMA contends
that the minimum energy recommended for euthanasia by gunshot of animals smaller than 180 kg is 407 J (AVMA 2013a:37).
Satisfying these conditions would require use of a handgun on
the order of a .357 Magnum to achieve these energy levels withmost readily available ammunition. This is clearly an inappropriate level of energy for most smaller species of mammals. It
is also the position of the AVMA that gunshot cannot be considered euthanasia in wildlife unless “bullet placement is to thehead (targeted to destroy the brain)” (AVMA 2013a:82). Sucha procedure, particularly with cartridges of the muzzle energy
specified by the AVMA, renders the skull and perhaps large
parts of the animal carcass unusable and is thus inconsistent
with most scientific collecting efforts that rely on obtaining
high-quality specimens for research. Gunshot through the brain
also risks aerosolizing brain tissue and thus may contribute to
the spread of rabies viruses or prions if present in the target
individual. Justification for deviations from approved AVMA
euthanasia methods for studies of wildlife can include citation of published literature (such as these ASM guidelines) andincompatibility with study requirements.
Field methods for killing should be as quick and painless as
possible, compatible with study design, and the size, behavior,and biology of the focal species. In case of injury resulting from
capture or handling, and when nothing can be done to alleviate
pain or distress or when recovery is not expected, euthanasia orhumane killing is indicated. Except when specifically excluded
by permit or law (e.g., with endangered/threatened species),
protocols involving fieldwork should explicitly indicate the circumstances for and method of euthanasia for voucher and distressed or injured animals to accommodate unplanned injuries
even when animal mortality is not an anticipated outcome. In
the case of Endangered Species, investigators should request
conditions on their permit that will allow them to terminate thelives of injured animals unlikely to survive in the wild unlesstreated, particularly where the animal is in pain or distress andveterinary care is not available. Importantly, investigators areadvised to list, and oversight bodies to accept, a range of methods to achieve a humane death for target and nontarget species under the variable environmental conditions that may be
encountered.
Euthanasia or humane killing should be conducted by personnel properly trained in the procedure used. Proper technique
includes a follow-up examination to confirm death. Standard
evidence of death include dilated pupils and absence of heartbeat as well as failure to respond to a toe pinch or touch of
the eye; cessation of breathing is not a sufficient criterion.
Decapitation, cervical dislocation, or thoracotomy (i.e., open
biopsy of lung, pleura, hilum, and mediastinum) may be conducted after administration of euthanizing drugs, as consistent
with study requirements, to insure that animals do not revive(AVMA 2013a). The AVMA considers decapitation and cervical dislocation, when properly performed by experienced
and trained personnel, acceptable methods of euthanasia forsome study designs and research needs, although justification
for use of these methods should include details concerning
intended use of the animals and the reasons why other euthanasia methods are unsuitable. Decapitation or cervical dislocation can be used as a method of euthanasia on animals that are
first anesthetized or sedated, but investigators should be awarethat administering sedatives or anesthesia before euthanasia
might add distress or impose additional pain on the animal. For
many small-bodied species, cervical dislocation can be accomplished efficiently in the field without sedation by experienced
personnel. Investigators should be aware, however, that thisprocedure can alter body measurements and damage skulls of

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

prohibited where its use is necessary to minimize animal suffering or is scientifically justified (such as under the oversightof an Institutional Animal Care and Use Committee)” (AVMA2011). AAALAC International similarly considers thoracic
compression acceptable in these situations. In their adoptionof the AVMA Guidelines as reference materials, AAALAC
International made a single exception, which focused on theuse of thoracic compression in wildlife studies (AAALAC
International 2015):
Exception: Thoracic (cardiopulmonary, cardiac) compression is a method used to euthanize wild small mammals and birds, mainly under field conditions. According to the 2013 Guidelines, thoracic compression is anunacceptable means of euthanizing animals that are notdeeply anesthetized or insentient due to other reasonsP.41, M3.12 and P.83, S7.6.3.3. The Council on Accreditation recognizes the need for the use of thoracic compression in conscious wild small birds and mammals insituations where alternate techniques are not feasible
or objectives of the protocol are such that the Institutional Animal Care and Use Committee (IACUC), and/or competent authority, grants approval for this method,training for the technique is provided, and its continued
approval is re-evaluated as more scientifically-based
data regarding its use becomes available.
Thoracic compression has the advantage of requiring no
additional equipment and thus can be used in any situation
where appropriately sized animals can be brought to hand. It
does not distort important body measurements, destroy needed
tissues and skeletal elements, or alter hormonal profiles via theintroduction of foreign substances. The ASM considers thoracic compression a humane method of killing when the investigator is skilled in this procedure and when the individuals to
be killed are sufficiently small that the thoracic cavity can becollapsed to prevent inspiration.
Methods of euthanasia acceptable to the AVMA—theiradvantages, disadvantages, and effectiveness—are reviewed in
the AVMA Guidelines for the Euthanasia of Animals (AVMA
2013a). This report also provides information on inhalantagents, noninhalant pharmaceutical agents, and physical methods of euthanasia. The American College of Laboratory Animal
Medicine (ACLAM) has also evaluated rodent euthanasia andidentified 3 issues of concern: euthanasia of fetal and neonatal rodents, use of carbon dioxide for euthanasia, and impactof euthanasia techniques on data collection. Publications by
ACLAM(https://www.aclam.org/Content/files/files/Public/
Active/report_rodent_euth.pdf) provide appropriate directives
on these topics.
For collecting methods using kill traps, it is important torecall the AVMA position that, although kill traps do not always
render a rapid or stress-free death consistent with their criteria
for euthanasia, situations exist when live traps and subsequenteuthanasia are not possible or when it might be more stressful
to animals or dangerous to humans to use live traps as opposed
to kill traps (AVMA 2013a). Finally, whether the termination

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smaller species, so its use on individuals that will be archived
as museum specimens should be carefully considered.
Although euthanasia of small mammals in field settings canbe accomplished using any of the techniques approved by the
AVMA, use of injectable controlled substances or inhalants canbe challenging due to risks to investigators and stress to the animals. Investigators and IACUCs are also reminded to verify thelegal requirements for using controlled substances away fromthe premises listed on DEA registration and for administration
by individuals other than licensed veterinarians if such will not
be present at the site of administration. If the method of killing includes controlled substances, toxins, or lead projectiles,
the PI and IACUC must consider the possibility of secondary
toxicity if the carcass is left in the field and consumed by otheranimals. These concerns might be alleviated by removing or
burying the carcass, but removal of carcasses, particularly oflarge animals, also deprives the biotic community of these valuable resources (Sikes and Bryan 2015). Further, the use of controlled substances requires DEA registration and availability of
the compounds themselves. Availability might be further compromised if the study involves foreign travel.
PIs and IACUCs should be aware that the Veterinary
Mobility Act of 2014 permits veterinarians, but not other DEA
registrants, to transport and use controlled substances at sites
other than their registered address. It is also important to notethat most states require a VCPR that may or may not extend
to wildlife and the use of controlled substances by someone
other than the veterinarian. As noted previously in the section
on the “Role of the veterinarian,” the language of Section 5of the model Veterinary Practices Act endorsed by the AVMAin 2013 (AVMA 2013b) precludes establishment of a VCPR
exclusively by telephonic or other electronic means. Thus, toprovide medical advice, including whether or not to euthanize
an animal on the basis of its condition, it would presumably
be necessary for a veterinarian to accompany the investigator on all field excursions. To insure compliance, investigators
and IACUCs should consult the language of the regulations
for the practice of veterinary medicine and the use of controlled substances in the state in which research activities are
conducted.
Thoracic compression offers an acceptable method of field
euthanasia for some mammals and has been used effectively
for decades by practicing mammalogists. Thoracic compression is not listed as an acceptable form of euthanasia in the2013 edition of the AVMA Guidelines for the Euthanasia of
Animals, but, as noted above, procedures other than those considered acceptable as euthanasia can be used for humane killing and can be authorized by the IACUC. The AVMA’s (2011)“Literature Review” on thoracic compression states that “whenscientifically justified, the IACUC has and should employ theauthority to approve killing techniques not listed as recognized forms of euthanasia. This might include approving thoracic compression where it represents the most humane option
available or practicable, or approving the use of drugs with
analgesic properties that may not be scheduled drugs.” The
AVMA further states that “thoracic compression should not be

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must be performed with a conscious respect for their effect onother animals (including human observers). Fear in other animals (including conspecifics and in some cases heterospecifics) can be triggered by distress vocalizations, fearful behavior,and release of odors and pheromones by a frightened animal(AVMA 2013a). Thus, killing should be done outside the perceptive range of other individuals whenever possible. Judgment
should be exercised with regard to killing animals in view ofthe general public without providing them training or education
about its necessity to avoid negative reactions to the proceduresby observers.

Vouchering of Specimens andAncillary Materials

Human Safety
Working with wild mammals, particularly in field situations,involves inherent risks, both biotic (e.g., bites, pathogens,parasites, and venomous plants and animals) and abiotic (e.g.,lightning and temperature extremes). Fortunately, most ofthese risks can be minimized with basic training, planning,
mentoring, and experience. Investigators have the responsibility to ensure that personnel handling, transporting, or maintaining wild-caught mammals are qualified and familiar with

Summary
These updated guidelines on the use of mammals, including wild species, emphasize that investigators are responsible
for compliance with federal and state guidelines regulating
care and use of animals in research, exhibition, and instruction. Investigators should work with IACUCs to develop
research protocols that allow scientific research objectives to

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Investigators must always plan for the disposition of animals
from wild populations when a study is completed or when
animals are procured unexpectedly during the study. The latter might result from incidental deaths when animals are founddead in traps, nets, or on roadways. All specimens and ancillary material generated from field studies should be deposited
with relevant data into an accredited research collection whenpossible. The ASM Systematic Collection Committee has compiled a list of accredited collections in the Western Hemisphere(Hafner et al. 1997). The information is available online at http://
www.mammalsociety.org/committees/systematic-collections.
Deposition of specimens and ancillary materials in permanentcollections maximizes benefits from each specimen generated,ensures access to valuable data by future investigators, andprovides vouchers for individuals or species used in publishedresearch. Further, in some instances, archived specimens may be
used in lieu of sacrificing additional individuals as part of futurestudies. The ASM recommends that when IACUCs approve
field studies that include collection or otherwise might resultin mortalities or the collection of potential surplus biologicalmaterial from either target or nontarget taxa, PIs designate an
ASM-approved systematic collection in which to deposit their
specimens. The submission of materials, of course, should becommensurate with the needs and capacities of the systematic collection. Exceptions to this practice should be justified
in the approved protocols. ASM recommends that investigators
coordinate with these institutions at the earliest possible stagesof project development in order to adequately budget for the
expenses involved in voucher deposition and curation.

the associated hazards (e.g., bites and exposure to body fluids)
as well as the requirements of the target species (e.g., bats—
Constantine 1988). With appropriate preparation and training,
investigators can adequately protect themselves and collaborators while conducting fieldwork with mammals (Kunz et al.
1997).
Many universities and other institutions offer field courses,
workshops, and online programs designed to provide investigators and students with proper training in fieldwork and activities with wild-caught mammals. Occupational health programs
also provide guidance for avoiding biological, chemical, andother hazards. Sources such as the CDC (1998, 1999; http://
www.cdc.gov/) or state health departments offer current information and precautions for personnel conducting epidemiological studies or working with populations suspected of posing
specific health risks. Additionally, the ASM provides updated
guidelines relative to hantavirus pulmonary syndrome formammalogists and wildlife researchers working with rodents;
these recommendations should be broadly applicable to fieldstudies of other mammal taxa (Kelt et al. 2010). The document by Kelt et al. (2010) also makes the important clarification that earlier published guidelines by the CDC (1998, 1999)
were never intended to apply to field investigators conducting
nonviral-focused research on rodents. Special precautions (e.g.,
vaccinations) to ensure human safety might be necessary whentransporting individuals known or suspected of carrying potentially lethal pathogens such as hantavirus or the rabies virus. In
areas where zoonotics are known to occur, bagging traps witha gloved hand and bringing them to a central processing areathat follows institutional biosafety recommendations might besufficient, although additional precautions might be required at
the time of final processing of the captured animal, dependingon the data required. Although chloroform is considered highly
hazardous to personnel due to attendant risks of cancer andliver toxicity (https://www.osha.gov/dts/chemicalsampling/data/CH_227600.html), use of this substance under open-air
field conditions might be appropriate because it kills ectoparasites that can pose risks to the researcher through transmissionof disease.
Many IACUCs will require the investigator to document intheir protocols the potential risks to human health and safety
while working with target species of wild-caught mammals.
However, investigators and IACUC members should remain
cognizant that risks from zoonoses vary depending on study
species, local environmental conditions, personnel attributes,
and the potential pathogens. Accordingly, the safety precautions employed should match potential risks.

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

become sufficiently removed from what is wild that we must be
prepared to answer the question “what good is it?” That is, wemust be able to communicate to a broad audience the applied
and theoretical values of research on wild mammals. Proactive
consideration of humane treatment of our study animals will
help prevent retroactive criticism of our ethics and our research.
With this in mind, the ultimate design of research programs,
including the methods and techniques to address research
objectives, are the responsibility of the investigator. Guidelines
can provide current information on ethical and regulatory standards, but they cannot replace individual judgment or the drive,
ingenuity, and curiosity that lead investigators to generate new
and insightful advances in science.

Acknowledgments
Many members of the ASM contributed to development ofthese guidelines, as have colleagues in the various organizations and agencies focused on ethical oversight of animal
research. Valuable comments and insights have been provided by mammalogists, PIs, and IACUC members fromdiverse organizations. The Committee particularly thanks
D. Reeder for her insights and advice regarding housing batsand J. Golcher-Benavides for preparing the Spanish abstract.
E. Paul, Executive Director of the Ornithological Council, andE. Lacey, President of the American Society of Mammalogists,
both provided particularly insightful comments on an earlier
draft. The manuscript also benefitted from anonymous referees during the review process. Finally, all IACUC members,
mostly volunteers, have a tremendous responsibility to assure
both institutional and federal oversight agencies and the publicthat all investigators understand and maintain compliance andthat studies that use animals do so with respect and knowledgeof the principles of animal care. We are grateful for their dedication, their service, and their feedback on this document.

Literature Cited
AAALAC International. 2015. Reference resources: wild animals.
http://www.aaalac.org/accreditation/resources_list.cfm. Accessed
17 December 2015.
ad hoc Committee for Animal Care Guidelines. 1985. Guidelines
for use of animals in research. Journal of Mammalogy 66:834.
http://mammalogy.org/uploads/committee_files/ACUC1985.pdf.
Accessed 2 May 2016.
ad hoc Committee on Acceptable Field Methods in Mammalogy.
1987. Acceptable field methods in mammalogy: preliminary guidelines approved by the American Society of Mammalogists. Journalof Mammalogy 68 Suppl.:1–18. http://mammalogy.org/uploads/
committee_files/ACUC1987.pdf. Accessed 2 May 2016.
American Veterinary Medical Association (AVMA). 2011. Welfare
implications of thoracic compression. https://www.avma.org/KB/
Resources/LiteratureReviews/Documents/thoracic_compression_
bgnd.pdf. Accessed 8 October 2015.
American Veterinary Medical Association (AVMA). 2013a. AVMA
Guidelines for the Euthanasia of Animals: 2013 edition. https://www.avma.org/KB/Policies/Documents/euthanasia.pdf. Accessed
8 October 2015.

Downloaded from http://jmammal.oxfordjournals.org/ by guest on June 10, 2016

be completed successfully while complying with animal welfare regulations. A rational, well-justified protocol, written succinctly and completely, will facilitate a positive and productive
dialog with the IACUC. The task of the IACUC is to provide
assurance to federal regulatory agencies and the public thatanimal research is being accomplished in accordance with theregulations and intent of the AWA and to work with researchersand educators to develop appropriate protocols. IACUCs must
be strong advocates for animal welfare and humane animal use
in research and education, especially when investigators provide clear justification for animal use and expertise upon which
the IACUC can rely. These interactions foster strong, positive,
and professional relationships between the IACUC and theinvestigator.
From initial design to completion of a study, investigators should exercise good judgment and prudence whenusing animals in research. IACUCs appreciate working withinvestigators who provide details of their research designs
and goals. The “3 Rs” of Reducing the number of individuals without compromising statistical validity or biologicalsignificance, Replacing “higher” animals with “lower” ones,
and Refinements of techniques and care to minimize pain or
distress to animals (NRC 2011) are important goals for field
mammalogy. A cap on the number of animals collected is usually imposed by state and sometimes federal permitting agencies and, likewise, is expected by the IACUC. Underestimatesof the number of animals needed for a study might invalidate results. Therefore, a sufficient number of animals (i.e.,
the number needed to meet research goals) must be clearly
requested and justified. “Replacement” in mammals might beachieved by using cell lines, voucher materials from previous studies, or computer simulations where possible. Further,larger mammals are not usually collected in surveys or for
genetic work. Rather, they can be subsampled by ear punchesor hair combs, or tissues might be requested from mammalian
research collections where this material is already be archived
as specimens. Other alternatives include using carcasses of
species of interest (especially larger carnivores or ungulates)that have been trapped or hunted for other purposes. However,investigators are reminded that such sources may introduce
undesirable biases associated with age, sex, or size. Finally,an example of “Refinement” might include using behavioral
responses as indicators of social dominance rather than outcomes of physical combat.
Most field investigators already embrace the ethical treatment of animals because of their respect for nature and their
dedication to wild species. The guidelines provided here weredeveloped to assist investigators in maintaining complianceand understanding the evolving suite of animal welfare regulations. How we view use of mammals in research does not differ
much from that of Joseph Grinnell when he visited Yosemite
Valley nearly 100 years ago. Knowledge of most aspects ofmammalian biology has advanced, but we still struggle witha basic understanding of our place in nature. Mammalogists
continue to explore the farthest reaches of the Earth. In contrast, the public and even some scientists in other fields have

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686

JOURNAL OF MAMMALOGY
Fowler, M. E. 1995. Restraint and handling of wild and domestic
animals. 2nd ed. Iowa State University Press, Ames.
Garsd, A., and W. E. Howard. 1981. A 19-year study of microtine population fluctuations using time-series analysis. Ecology
62:930–937.
Getz, L. L., and G. O. Batzli. 1974. A device for preventing disturbance of small mammal live-traps. Journal of Mammalogy
55:447–448.
Greer, L. L., J. Whaley, and T. K. Rowles. 2001. Euthanasia. Pp.
729–740 in CRC handbook of marine mammal medicine. 2nded. (L. A. Dierauf and F. M. D. Gulland, eds.). CRC Press, Boca
Raton, Florida.
Grinnell, J. 1928. Recommendations concerning the treatment oflarge mammals in Yosemite National Park. Journal of Mammalogy
9:76.
Guidelines for Preparing USDA Annual Reports and Assigning USDA
Pain and Distress Categories. http://oacu.od.nih.gov/ARAC/documents/USDA_Reports.pdf. Accessed 17 December 2015.
Hafner, M. S., W. L. Gannon, J. Salazar-Bravo, and S. T. AlvarezCastañeda. 1997. Mammal collections in the Western Hemisphere:a survey and directory of existing collections. American Society of
Mammalogists, Allen Press, Lawrence, Kansas.
Hare, B., et al. 2005. Social cognitive evolution in captive foxes isa correlated by-product of experimental domestication. Current
Biology 15:226–230.
Hart, E. B. 1973. A simple and effective live trap for pocket gophers.
American Midland Naturalist 89:200–202.
Hawes, M. L. 1977. Home range, territoriality, and ecological separation in sympatric shrews, Sorex vagrans and Sorex obscurus.
Journal of Mammalogy 58:354–367.
Hernádi, A., A. Kis, B. Turcsán, and J. Topál. 2012. Man’s underground best friend: domestic ferrets, unlike the wild forms,
show evidence of dog-like social-cognitive skills. PLoS ONE
7:e43267.
Howard, W. E., and E. M. Brock. 1961. A drift fence pit-trap that
preserves captured rodents. Journal of Mammalogy 42:386–391.
Interagency Research Animal Committee (IRAC). 1985. US
Government Principles for Utilization and Care of Vertebrate
Animals Used in Testing, Research, and Training. Federal Register,
May 20, 1985. Office of Science, Washington, D.C. http://grants.
nih.gov/grants/olaw/references/phspol.htm#USGovPrinciples.
Accessed 17 December 2015.
Kaufman, D. W., and G. A. Kaufman. 1989. Burrow distribution of thethirteen-lined ground squirrel in grazed mixed-grass prairie: effectof artificial habitat structure. Prairie Naturalist 21:81–83.
Kelt, D. A., M. S. Hafner , and the American Society of
M ammalogists’ A d H oc C ommittee for G uidelines on
H andling R odents in the F ield. 2010. Updated guidelines
for protection of mammalogists and wildlife researchers fromhantavirus pulmonary syndrome (HPS). Journal of Mammalogy
91:1524–1527.
Klailova, M., K. Hodgkinson, and P. C. Lee. 2010. Behavioral
responses of one western lowland gorilla (Gorilla gorilla
gorilla) group at Bai Hokou, Central African Republic, to tourists, researchers and trackers. American Journal of Primatology
72:897–906.
Kreeger, T. J., and J. M. Arnemo. 2012. Handbook of wildlife chemical immobilization. 4th ed. Private Publication.
Kuehn, D. W., T. K. Fuller, L. D. Mech, W. J. Paul, S. H. Fritts,
and W. E. Berg. 1986. Trap-related injuries to gray wolves in
Minnesota. Journal of Wildlife Management 50:90–91.

Downloaded from http://jmammal.oxfordjournals.org/ by guest on June 10, 2016

American Veterinary Medical Association (AVMA). 2013b. Model
Veterinary Practice Act—January 2013. https://www.avma.org/
KB/Policies/Pages/Model-Veterinary-Practice-Act.aspx. Accessed
17 December 2015.
Asper, E. D. 1975. Techniques of live capture of smaller
Cetacea. Journal of the Fisheries Research Board of Canada
32:1191–1196.
Baker, R. J., and S. L. Williams. 1972. A live trap for pocket gophers.
Journal of Wildlife Management 36:1320–1322.
Barclay, R. M. R., and G. P. Bell. 1988. Marking and observational
techniques. Pp. 59–76 in Ecological and behavioral methods forthe study of bats (T. H. Kunz, ed.). Smithsonian Institution Press,
Washington, D.C.
Barnard, S. M. 2011. Bats in captivity. Vol. 3. Diet and feeding–environment and housing. Logos Press, Washington, D.C.
Beacham, T. D., and C. J. Krebs. 1980. Pitfall versus live-trap enumeration of fluctuating populations of Microtus townsendii. Journalof Mammalogy 61:486–499.
Belyaev, D. K., and L. M. Trut. 1964. Behaviour and reproductive function of animals. I. Correlation of behaviour type with thetime of reproduction and fertility. Bulletin de la Société Imperiale
des Naturalistes de Moscou 69:5–19 [in Russian; explained in:Belyaev, D. K. 1979. Destabilizing selection as a factor in domestication. Journal of Heredity 70:301–308].
Boice, R. 1972. Water addiction in captive desert rodents. Journal of
Mammalogy 53:395–398.
Braden, G. C., A. K. Brice, and F. C. Hankenson. 2015. Adverse
effects of vapocoolant and topical anesthesia for tail biopsy of preweanling mice. Journal of the American Association for Laboratory
Animal Science 54:291–298.
Braun, C. E. 2005. Techniques for wildlife investigations and management. Wildlife Society, Bethesda, Maryland.
Bush, M. 1995. Methods of capture, handling, and anesthesia. Pp.
25–40 in Wild mammals in captivity: principles and techniques (D.
G. Kleiman, M. E. Allen, K. V. Thompson, and S. Lumpkin, eds.).
University of Chicago Press, Chicago, Illinois.
Canadian Council on Animal Care. 1993. Guide to the care and useof experimental animals. 2nd ed. (E. D. Olfert, B. M. Cross, and A.
A. McWilliams, eds.). Canadian Council on Animal Care, Ottawa,
Ontario, Canada. Vol. 1.
Centers for Disease Control and Prevention (CDC). 1998.
Hantavirus pulmonary syndrome—Colorado and New Mexico.
Morbidity and Mortality Weekly Report 47:449–452.
Centers for Disease Control and Prevention (CDC). 1999. Update:hantavirus pulmonary syndrome—United States. Morbidity andMortality Weekly Report 48:521–525.
Constantine, D. G. 1988. Health precautions for bat researchers. Pp. 491–526 in Ecological and behavioral methods for the
study of bats (T. H. Kunz, ed.). Smithsonian Institution Press,
Washington, D.C.
Darwin, C. 1868. The variation of animals and plants under domestication. John Murray, London, United Kingdom. Vol. 1 and 2.
Davidson, A. D., R. R. Parmenter, and J. R. Gosz. 1999. Responsesof small mammals and vegetation to a reintroduction of Gunnison’s
prairie dogs. Journal of Mammalogy 80:1311–1324.
Dierauf, L. A., and F. M. D. Gulland (eds.). 2001. CRC handbook ofmarine mammal medicine. 2nd ed. CRC Press, Boca Raton, Florida.
Do, R., J. Shonfield, and A. G. McAdam. 2013. Reducing accidental
shrew mortality associated with small-mammal livetrapping II: afield experiment with bait supplementation. Journal of Mammalogy
94:754–760.

SIKES ET AL.—GUIDELINES FOR ANIMAL USE<?>

SIKES ET AL.—GUIDELINES FOR ANIMAL USE

Powell, R. A., and G. Proulx. 2003. Trapping and marking terrestrial
mammals for research: integrating ethics, performance criteria,
techniques, and common sense. Institute for Laboratory Animal
Research Journal 44:259–276.
Reeder, D. M., K. A. Field, and M. H. Slater. 2015. Balancing
the costs of wildlife research with the benefits of understanding a panzootic disease, white–nose syndrome. ILAR Journal
56:275–282.
Rothmeyer, S. W., M. C. McKinstry, and S. H. Anderson. 2002.
Tail attachment of modified ear-tag radio transmitters on beavers.
Wildlife Society Bulletin 30:425–429.
Rusak, B., and I. Zucker. 1975. Biological rhythms and animal
behavior. Annual Review of Psychology 26:137–171.
Ryan, J. 2011. Mammalogy techniques manual. 2nd ed. Lulu,
Raleigh, North Carolina.
Schmintz, S. D. 2005. Capturing and handling wild animals. Pp. 239–
285 in Techniques for wildlife investigations and management (C.
E. Braun, ed.). Wildlife Society, Bethesda, Maryland.
Sherwin, R. E., S. Haymond, D. Stricklan, and R. Olson. 2002.
Freeze branding for permanently marking temperate bat species.
Wildlife Society Bulletin 30:97–100.
Sikes, R. S., and J. A. Bryan II. 2015. IACUC Considerations forthe use of wildlife in research and education. ILAR Journal
56:335–341.
Sikes, R. S., W. H. Gannon, and the Animal Care and Use Committeeof the American Society of Mammalogists. 2011. Guidelines of
the American Society of Mammalogists for the use of wild mammals in research. Journal of Mammalogy 92:235–253. http://mammalogy.org/uploads/committee_files/ACUC2011.pdf. Accessed 2
May 2016.
Sikes, R. S., and E. Paul. 2013. Fundamental differences between
wildlife and biomedical research. ILAR Journal 54:5–13.
Sikes, R. S., E. Paul, and S. J. Beaupre. 2012. Standards for wildlife research: taxon-specific guidelines versus US Public HealthServices policy (with cover photo). BioScience 62:830–834.
Society for the Study of Animal Behaviour. 2006. Guidelines forthe treatment of animals in behavioural research and teaching.
Animal Behaviour 71:245–253.
Strathearn, S. M., J. S. Lotimer, G. B. Kolenosky, and W.
M. Lintack. 1984. An expanding break-away radio collar for black
bear. Journal of Wildlife Management 48:939–942.
Thomas, D. W. 1995. Hibernating bats are sensitive to nontactile
human disturbance. Journal of Mammalogy 76:940–946.
Trut, L., I. Oskina, and A. Kharlamova. 2009. Animal evolution
during domestication: the domesticated fox as a model. BioEssays
31:349–360.
United States Department of Agriculture (USDA). 2015a. Animal
Care Policy Manual 2015. https://www.aphis.usda.gov/animal_
welfare/downloads/Animal%20Care%20Policy%20Manual.pdf,
Accessed 17 December 2015.
United States Department of Agriculture (USDA). 2015b. Animal
Welfare Inspection Guide. https://www.aphis.usda.gov/animal_
welfare/downloads/Animal%20Care%20Inspection%20Guide.
pdf. Accessed 12 October 2015.
Walker, W. A. 1975. Review of the live-capture fishery forsmaller cetaceans taken in southern California waters for public display. Journal of the Fisheries Research Board of Canada
32:1197–1211.
West, P. M., and C. Packer. 2002. Sexual selection, temperature, andthe lion’s mane. Science 297:1339–1343.

Downloaded from http://jmammal.oxfordjournals.org/ by guest on June 10, 2016

Kunz, T. H., and S. Parsons (eds.). 2009. Ecological and behavioral
methods for the study of bats. 2nd ed. Johns Hopkins University
Press, Baltimore, Maryland.
Kunz, T. H., R. Rudran, and G. Gurri-Glass. 1997. Human healthconcerns. Appendix 2. Pp. 255–264 in Measuring and monitoring
biological diversity: standard methods for mammals (D. E. Wilson,
F. R. Cole, J. D. Nichols, R. Rudran, and M. S. Foster, eds.).
Smithsonian Institution Press, Washington, D.C.
Lacy R. C., G. Alaks, and A. Walsh. 2013. Evolution of Peromyscus
leucopus mice in response to a captive environment. PLoS ONE
8:e72452.
Layne, J. N. 1987. An enclosure for protecting small mammal traps
from disturbance. Journal of Mammalogy 68:666–668.
Lollar, A., and B. Schmidt-French. 1988. Captive care and medical reference for the rehabilitation of insectivorous bats. Bat World
Sanctuary.
Martin, R. E., R. H. Pine, and A. F. DeBlase. 2011. A manual of
mammalogy: with keys to families of the world. Waveland Press,
Long Grove, Illinois.
Munro, R. H. M., S. E. Nielsen, M. H. Price, G. B. Stenhouse, and
M. S. Boyce. 2006. Seasonal and diel patterns of grizzly beardiet and activity in west-central Alberta. Journal of Mammalogy
87:1112–1121.
National Institutes of Health/Office of Laboratory Animal
Welfare (NIH/OLAW). 2015. Public Health Service Policy on
Humane Care and Use of Laboratory Animals. National Institutesof Health, Department of Health and Human Services, Bethesda,
Maryland.
National Research Council (NRC). 2008. Recognition and alleviation of distress in laboratory animals. National Academies Press,
Washington, D.C.
National Research Council (NRC). 2009. Recognition and alleviation of pain in laboratory animals. National Academies Press,
Washington, D.C.
National Research Council (NRC). 2011. Guide for the care and useof laboratory animals. National Academy Press, Washington, D.C.
Orlans, F. B. (ed.). 1988. Field research guidelines: impact on Animal
Care and Use Committees. Scientists Center for Animal Welfare,
Bethesda, Maryland.
O’Shea, T. J., and M. A. Bogan (eds.). 2003. Monitoring trends inbat populations in the United States and territories: problems andprospectus. United States Geological Survey Information andTechnology Report ITR 20030003.
Ostfeld, R. S., M. C. Miller, and K. R. Hazler. 1996. Causes
and consequences of tick (Ixodes scapularis) burdens on whitefooted mice (Peromyscus leucopus). Journal of Mammalogy
77:266–273.
Paluch, L. R., C. C. Lieggi, M. Dumont, S. Monette, E. R. Riedel,and N. S. Lipman. 2014. Developmental and behavioral effects of
toe clipping on neonatal and preweanling mice with and without
vapocoolant anesthesia. Journal of the American Association forLaboratory Animal Science 53:132–140.
Parmenter, R. R., et al. 2003. Small-mammals density estimates: afield comparison of grid-based vs web-based density estimators.
Ecological Monographs 73:1–26.
Paul, E., and R. S. Sikes. 2013. Wildlife researchers running the permit maze. ILAR Journal 54:14–23.
Paul E., R. S. Sikes, S. J. Beaupre, and J. C. Wingfield. 2015. Animal
Welfare Policy: implementation in the context of wildlife research.
ILAR Journal 56:312–334.

687

688

JOURNAL OF MAMMALOGY

Wilkinson, G. S., and J. W. Bradbury. 1988. Radio telemetry: techniques and analysis. Pp. 105–124 in Ecological and behavioral
methods for the study of bats (T. H. Kunz, ed.). Smithsonian
Institution Press, Washington, D.C.
Willoughby, J. R., N. B. Fernandez, M. C. Lamb, J. A. Ivy, R.
C. Lacy, and J. A. DeWoody. 2015. The impacts of inbreeding,drift and selection on genetic diversity in captive breeding populations. Molecular Ecology 24:98–110.
Wilson, D. E., F. R. Cole, J. D. Nichols, R. Rudran, and M. S. Foster(eds.). 1996. Measuring and monitoring biological diversity:
standard methods for mammals. Smithsonian Institution Press,
Washington, D.C.

Wilson, D. E., and D. M. Reeder (eds.). 2005. Mammal species of
the world: a taxonomic and geographic reference. 3rd ed. Johns
Hopkins University Press, Baltimore, Maryland. Vol. 1 and 2.
Wingfield, J. C. 2015. Commentary: guidance for field biology andother studies on wildlife species. ILAR Journal 56:271.
Wood, M. D., and N. A. Slade. 1990. Comparison of ear-tagging
and toe-clipping in prairie voles, Microtus ochrogaster. Journal of
Mammalogy 71:252–255.

Submitted 9 January 2016. Accepted 5 April 2016.
Associate Editor was Patrick Zollner.

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