A six-booklet 

series on 

providing 

appropriate 

enrichment 

for baboons, 

capuchins, 

chimpanzees, 

macaques, 

marmosets and 

tamarins, and 

squirrel monkeys.
Contents

......

Contents

Introduction	 	 	 	 	 	 	 Page 4

Baboons	 	 	 	 	 	 	 Page 6

Background

Social World

Physical World

Special Cases

Problem Behaviors

Safety Issues

References

Common Names of the Baboon

Capuchins	 	 	 	 	 	 	 Page 17

Background

Social World

Physical World

Special Cases

Problem Behaviors

Safety Issues

Resources

Common Names of Capuchins

Chimpanzees 	 	 	 	 	 	 	 Page 28

Background

Social World

Physical World

Special Cases

Problem Behaviors

Safety Issues

Resources

Common Names of Chimpanzees

contents continued on next page ...
Contents

Contents continued...

Macaques	 	 	 	 	 	 	 Page 43

Background

Social World

Physical World

Special Cases

Problem Behaviors

Safety Issues

Resources

Common Names of the Macaques

Sample Pair Housing SOP -- Macaques

Marmosets and Tamarins		 	 	 	 	 Page 58

Background

Social World

Physical World

Special Cases

Safety Issues

References

Common Names of the Callitrichids

Squirrel Monkeys	 	 	 	 	 	 Page 73

Background

Social World

Physical World

Special Cases

Problem Behaviors

Safety Issues

References

Common Names of Squirrel Monkeys

For more information, contact OLAW at NIH, tel	(301) v.

NIH Publication Numbers: 

05-5745 Baboons

05-5746 Capuchins

05-5748 Chimpanzees

05-5744 Macaques

05-5747 Marmosets and Tamarins

05-5749 Squirrel Monkeys

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.....................................................................................................................
Introduction

Nonhuman primates maintained in captivity have a valuable role in education

and research. They are also occasionally used in entertainment. The scope of

these activities can range from large, accredited zoos to small “roadside” exhibits; from national primate research centers to small academic institutions with

only a few monkeys; and from movie sets to street performers. Attached to these

uses of primates comes an ethical responsibility to provide the animals with an

environment that promotes their physical and behavioral health and well-being. Thus, an obligation is entailed that those individuals/institutions caring for

captive primates should make every effort to ensure adequate veterinary care and

husbandry are provided, that the animals are housed in appropriate facilities,

and that as broad a range of species-typical behaviors are able to be expressed by

the animals as is possible for the captive environment.

This book serves as an introduction to the basic behavior and environmental

enrichment of several species of nonhuman primates that are more commonly

used in education, research and entertainment. In many ways, this book is

meant to be a “how to” manual; it is not intended to be a broad scientific review

of the primate behavior and enrichment literature. The fundamental premise

taken throughout each chapter is that for an enrichment program to be effective, there must be a basic understanding of the biology and behavior of the

primate species. The species addressed in this series are: baboons, capuchins,

chimpanzees, macaques, marmosets and tamarins, and squirrel monkeys. Each

species-section can be read as a stand-alone document without need to reference

the other sections. This then allows the user to distribute the different sections

to personnel caring for the specific animals.

Each section is divided into five parts: 1) Background, comprised of the habitat

of the primate, the physical features of the primate, its psychological and/or

......

Introduction
social behavior, and its mating and reproductive behavior; 2) Social World;

3) Physical World; 4) Special Cases, describing any age-related considerations

and concerns associated with individual housing; and 5) Problem Behaviors.

The content of this series has been provided by members of the Association of

Primate Veterinarians (APV) and the American Society of Primatologists (ASP)

who have special expertise in the species addressed. This book is intended to be

a primer because it is, indeed, an introduction to the subject of environmental

enrichment for primates housed in a diversity of conditions. A list of references

and/or other resources (principally on-line) is provided at the end of each chapter that provide additional guidance. The use of scientific references has been

limited, but should the reader desire more information about a specific subject,

the links at the end of the sections will provide direction to obtaining additional

detailed information. Readers are also directed to the National Research Council

publication, the Guide for the Care and Use of Laboratory Animals (1996) and

the U.S. Department of Agriculture’s (USDA) Animal Welfare Regulations to

review the regulatory requirements of the Public Health Service and the USDA

for the provision of environmental enrichment.

The APV and ASP wish to thank the Office of Laboratory Animal Welfare, in

particular Ms. Carol Wigglesworth and Dr. Axel Wolff; the U.S. Department of

Agriculture/Animal Care, in particular Dr. Chester Gipson; and Ms. Dale Feurer, editor, and Ms. Lori Wieder, graphics and layout production, for their assistance with this project. The authors acknowledge the helpful contributions of

Dr. David J. Shepherdson, Conservation Program Scientist, Metro Washington

Park Zoo; Ms. April D. Truitt, Director, Primate Rescue Center, Inc.; and Ms.

Kathleen Conlee, Program Officer, Humane Society of the United States. Special thanks also go to the chapter authors Dr. Christian Abee, Dr. Kate Baker,

Dr. Linda Brent, Dr. Thomas Butler, Dr. Jeffrey Fite, Dr. Dorothy Fragazy, Dr.

Jeffrey French and Dr. A. Michele Schuler, and to the reviewers from the American Society of Primatologists and the Association of Primate Veterinarians.

—Kathryn Bayne, M.S., Ph.D., D.V.M., DACLAM, CAAB

Editor, Working Group

This project is dedicated to the memory of Dr. Sylvia Taylor, Veterinary 

Medical Officer, Animal Care, U.S. Department of Agriculture, who 

was a proponent of providing enrichment to nonhuman primates and 

was generous in sharing her knowledge and expertise in this regard. 

Introduction
enrichment

Linda Brent, Ph.D.

Chimp Haven, Inc.

Southwest Foundation for Biomedical Research

Thomas M. Butler, D.V.M., M.S., DACLAM 

Southwest Foundation for Biomedical Research

Baboons

for nonhuman primates
......



Baboons

......

Baboons

Background

Habitat

Baboons live in many parts of Africa, primarily in dry savannah woodlands. 

They are the largest and most terrestrial, or ground dwelling, of the cheek pouch 

monkeys (Cercopithecines). There are five types of baboons--olive, yellow, red, 

chacma and hamadryas--which may interbreed to form hybrids in captivity 

and, in some places, in the wild. Olive and Yellow baboons are found in many 

areas of equatorial Africa and are typically called savannah baboons. Hamadryas 

baboons inhabit the highlands of Ethiopia. Red or guinea baboons live in gallery 

forest and woodland savannas of West Africa. Chacma baboons reside in southern African woodland to semi-desert habitats. Home ranges of baboons may 

cover approximately 10,000 acres.

Physical Features 

Baboons walk on all four limbs, and their forelimbs and hindlimbs are approximately the same size. Males (44 to 53 lbs.) are much larger than females (26 to 

35 lbs.) and have long canine teeth. The tail is moderately long and is typically 

held in a characteristic U-shape. Baboons have prominent ischial callosities, 

which are bright red in some species. They have a prominent muzzle. The life 

span of a baboon ranges from 20 to 30 years. 

Behavior 

Baboons have a number of distinct vocalizations, including:

• Alarm bark – loud, rapid, sound to indicate potential threat or challenge

• Lipsmack – short, repeated clicking of the lips or tongue, associated with 

friendly behavior and approaches to a dominant individual or infant
Baboons

......



• Grunt – low, snort-like sound, often associated with group unity or 

communication

• Ooer – moo-like sound made by infants in distress

• Gek – quick “aaack” indicating disturbance

• Scream – shrill, loud, high-pitched sound made when aggressive or fearful 

Other gestures that indicate a threat or aggression include brow raises that display white eyelids, yawns directed at a specific individual, hitting the ground or 

object rapidly (slapping), teeth grinding, and staring intently at another individual.

Baboons travel and feed during the day and sleep in trees or cliffs at night for 

protection from predators. Being very good scavengers, baboons can survive in 

areas that other primates cannot. They spend about half of their waking hours 

looking for, processing, and eating food. They may dig up roots and eat insects, 

lizards, small mammals, and even crabs or fish if near water. In captivity, they 

spend more time in social interaction and much less time feeding. Captive baboons can be fed a complete, commercially available diet, supplemented with a 

variety of other fruits and vegetables. 

 

Mating and 

Reproduction 

The female’s skin 

on her rump, or 

perineal area, swells 

greatly according 

to her menstrual 

cycle. This is usually referred to as 

sex skin. Hamadryas females have 

a particularly large 

sex skin swelling. 

During the period 

of maximal swelling, 

she will ovulate and 

be most receptive 

to mating. The sex Prominent sex skin on a baboon (photo by E. Glover, Southwest 

Foundation for Biomedical Research (SFBR)).
......



Baboons

skin becomes flat and takes on a bright red or purple hue when she becomes 

pregnant. Gestation lasts from 18 to 24 weeks. Infants are born black with pink 

faces and bottoms. They need the mother’s protection, milk and transportation 

to survive. At about four to six months, the infant begins to change to the color 

of the adults. They are generally weaned by colony managers around five to six 

months of age, and although the natural weaning process will vary among baboon species, it generally occurs between one to two years of age. They become 

sexually mature at about three to five years.

Social World

Baboons live in a strict society. They clearly know their rank in the group and 

the rank of others, and behave toward others as appropriate for their dominance 

status. Baboons are very protective of infants and tolerant of juveniles, and 

males may carry and groom infants on occasion. Friendships have been reported 

between particular males and females.

......

A social group of baboons (photo by E. Glover, SFBR).
Baboons

......



Baboons are incredibly social animals and should not be kept isolated. Infants 

should be kept with their mothers for at least a year to develop normal social 

skills. Compared to most other primates, baboons are fairly easy to put together 

into groups. Preferably, subspecies should be kept together, or at least in groups 

with similar structure as found in the wild, which can differ among and within 

species, probably based on the nature of the habitat in which the animals are 

found. Groups that combine a single male with multiple females are most common in captivity, but all-male groups also can be formed. Groups with multiple 

females and males are more difficult unless there is enough space for them to 

avoid aggression, especially fights over mates.

Physical World

Housing

In general, 

baboons are 

quite hardy and 

adaptable. They 

can be successfully housed in a 

variety of captive 

conditions, from 

indoor cages to 

large outdoor 

semi-free ranging enclosures. 

Sturdy cages are 

required because 

baboons are 

strong and will manipulate the cage a great deal. Cages should be constructed 

to prevent the baboons from pulling off pieces of the cage and eating them. 

Baboons favor high perches. While some facilities have successfully used old tires 

and ropes for resting areas and swings, others have reported that the baboons eat 

Baboon sleeping off the ground on a high shelf (photo by E. Glover, SFBR).

......
......



Baboons

the items and become sick. Alternative 

swings and resting areas can be constructed from metal or polyvinyl chloride. Large areas and/or visual barriers are 

necessary so that low-ranking individuals 

can avoid others. If aggression within the 

group is a problem, elevated resting areas 

or hiding areas should be added to help 

mitigate the aggression.

Enrichment

Feeding is a popular enrichment activity for baboons, who are very motivated 

by food. Due to their strict dominance 

hierarchy, only the most dominant male 

and female may eat food items provided 

to a group. To avoid this type of monopolization, it is best to scatter smaller 

food items all around the enclosure. In 

addition to feeding commercially available, nutritionally balanced diets, baboons can be offered food enrichments such 

as grains, fruits, vegetables, vegetation, bark, coconuts, peanut butter, dry fruit, 

honey, candy, cereal. The feeding of treats should not compromise the baboon’s 

appetite for the nutritionally balanced food, so the quantity of treats provided 

should be monitored closely. Baboons will also ingest items that are not healthy 

for them, such as rocks, wire, metal or other harmful materials. Bloat has been 

reported if baboons eat too many orange peels or gas-producing vegetables (e.g., 

broccoli), and they may become impacted if they eat too much hair, hay or 

wood.

 

Objects containing food must be heavy or they will be destroyed quickly. Puzzles 

made of sturdy materials, such as polyvinyl chloride (PVC), can be filled with 

treats. Toys on short chains can be coated with honey and dipped in grain, then 

frozen and hung on the cage, for a treat. Once the baboons eat the food, they 

can then play with the toy that remains. Frozen blocks of juice or water with 

fruit inside can be given to the baboons in the cage or enclosure, or hung from 

the roof with a chain. Locking nuts are necessary so the baboons do not unscrew 

the devices. Also, sturdy clips should be used to attach the device, and puzzles 

Baboon using a recycled and modified soap 

barrel for perching (photo by E. Glover, SFBR).
Baboons

......



should be removed 

when empty to keep 

the baboons from 

breaking them.

Since baboons manipulate and chew 

many objects, very 

sturdy dog toys make 

good baboon toys 

(e.g., rigid plastic 

balls; large, thick 

rubber toys; hard 

nylon dog chews). 

Hard, nontoxic logs 

or wood pieces can 

be used for chewing and even as perches. Pieces at least two to three inches in 

diameter are best so that they are not immediately destroyed. Wood items must 

be replaced on occasion 

and should be monitored 

so that large pieces or 

slivers do not endanger 

the baboons. 

Other types of enrichment include videotapes, mirrors, and wind 

chimes, which are especially helpful enrichment 

for singly caged baboons. 

Several commercially 

available enrichment 

items, including fleece 

boards made for grooming and plastic balls with 

holes in them and filled 

with treats, are not as 

useful for baboons and 

Baboon with durable toy (photo by E. Glover, SFBR).

Baboon on a shelf in enclosure (photo by E. Glover, SFBR).
......



Baboons

probably not worth the 

expense.

New items may receive 

a lot of attention, but 

baboons will quickly tire of 

them. Replacement of toys 

or devices at regular intervals is important to keep 

the animal’s interest high.

 

Special Cases

Older animals usually will become more isolated from the troop, but not always. 

Since they can’t climb as well as their younger counterparts, they should have 

plenty to do at ground level. Food and water must be accessible near the floor, 

and food will have to be softened by soaking in water if the older baboon has 

lost some teeth.

Infants are curious creatures and will explore any opening. It is essential to make 

sure that all possible openings are covered to prevent entrapment or escape.

Baboon with Kong® toy 

(photo by E. Glover, SFBR).

......
Baboons

......



Problem Behaviors

Like other monkeys, baboons can develop problem behaviors for a number of 

reasons. Being taken away from the mother and raised by humans is a major 

cause of later abnormal behavior patterns, as the infant must learn to cope with 

the loss of the mother and grow up in an artificial environment. Boredom, stress 

and, ultimately, problem behavior may result from confinement in small enclosures, lack of enrichment activities, solitary housing, or housing that does not 

afford the animal ways to avoid more dominant individuals or frightening situations.

Examples of abnormal behavior patterns to watch for are hair eating and regurgitation. Extra feeding with food or “toys” can help to alleviate these behaviors that 

are related to boredom and not enough time spent feeding. Orphaned baboons 

often develop self-directed behaviors, such as self-sucking and clinging. They 

need appropriate attachment figures if they cannot be kept with the mother. One 

possibility is a mobile surrogate made of fleece-wrapped, three-inch PVC hung 

from the top of the cage. Exposure to peers or other friendly adults is critical 

to the orphan for normal development. It is very difficult to eliminate problem 

behaviors developed during infancy, but some individuals may be helped by 

gradually introducing them to friendly, perhaps younger, social partners.

More severe problems, such as self-biting, also have been reported in captive 

baboons. Intensive efforts are required to reduce or eliminate this problem. A 

daily program of enrichment, with documentation of items that seem to reduce 

the frequency of self-biting is required and may need to be continued for the life 

of the baboon. For individuals that increase self-aggressive behaviors when new 

enrichment items are provided, enrichment provided outside of the cage (such as 

in association with positive reinforcement training) can be more effective until 

the behavior is under control. Abnormal behaviors in baboons housed alone are 

greatly decreased when the animals are placed into social groups.

Some baboons are also very aggressive to one another, causing problems when 

they are put into new groups. This “hyper aggression” is more common in males 

and difficult to control, and it may be necessary to try multiple different partners, including females or even juveniles. It is important to observe the individual 

to determine what sets off the aggression, since it may be related to commotion 

......
......



Baboons

in the environment, feeding time, etc. This can help to indicate options that 

may reduce the behavior (e.g., moving to another cage, separating during feeding).

It is far more humane for the baboon and less work for the person to keep 

abnormal behavior patterns from developing. This can usually be accomplished 

by doing two things. First, keep infants with their mothers for about one year. 

Second, house baboons in social groups in large enclosures with enrichment to 

occupy their time.

Safety Issues

While they may have a reputation for being aggressive due to their size and large 

canines, baboons actually are mild-mannered and easy to work with compared 

to other primate species. They have elaborate threat displays that help to keep 

the peace in large groups, but actual aggression resulting in injury is not common. Given the size of baboons, it is not easy to “force” them into doing something, such as moving into a new cage. Greater success and a better relationship 

will develop if the baboons are treated with respect and positive interactions 

– and they will respond with cooperation and friendly behavior. 

Baboons can be trained with positive reinforcement to cooperate during a 

variety of management procedures, including transferring them to new areas, 

getting them to show parts of their body for inspection, and performing certain medical tests (i.e., blood pressure measurement). Given their keen interest 

in food rewards, ability to learn quickly, and generally relaxed attitude around 

humans, they make good pupils. People can maintain positive interactions with 

baboons by providing treats to the baboons and taking care not to frighten them 

by staring at them or moving suddenly.

Baboons should be sedated during physical examinations and other procedures 

that require physical handling, especially if they weigh more than about 11 to 15 

lbs. The best way to move them is via a system of chutes and doors. 

......
Baboons

......

10

References

Altmann J. 2001. Baboon Mothers and Infants. Chicago: University of Chicago 

Press.

Brent L, Koban T, Ramirez S. 2002. Abnormal, abusive and stress-related 

behaviors in baboon mothers. Biol Psychiatry 52(11):1047-56.

Brent L, Belik M. 1997. The response of group-housed baboons to three 

enrichment toys. Lab Anim. 31(1):81-5.

Brent L, Weaver D. 1996. The physiological and behavioral effects of radio on 

singly housed baboons. J Med Primatol. 25(5):370-4.

Easley SP, Coelho Jr. AM. 1991. Is lipsmacking an indicator of social status in 

baboons? Folia Primatol (Basel) 56(4):190-201.

Fortman JD, Hewett TA, Bennett BT. 2002. The Laboratory Nonhuman 

Primate. Boca Raton, FL: CRC Press. 

Kessel A, Brent L. 2001. The rehabilitation of captive baboons. J Med Primatol. 

30(2):71-80.

National Research Council. 1998. The Psychological Well-Being of Nonhuman 

Primates. Washington, D.C., National Academy Press.

Primate Lit: A Bibliographic Database for Primatology. 

http://primatelit.library.wisc.edu

Rowe N. 1996. The Pictorial Guide to the Living Primates. East Hampton, NY: 

Patagonias Press.

Smuts B. 2001. Friendship between the sexes: forming enduring relationships 

in an olive baboon troop. In The New Encyclopedia of Mammals, edited by D. 

MacDonald, 360-361. Oxford, England: Oxford University Press.

Common Names of the Baboons

Papio anubis or P. hamadryas anubis: Olive baboon, Anubis baboon

P. cynocephalus or P. hamadryas cynocephalus: Yellow baboon, Savanna baboon

P. hamadryas or P. hamadryas hamadryas: Hamadryas baboon, Sacred baboon

P. papio or P. hamadryas papio: Western baboon, Guinea baboon

P. ursinus or P. hamadryas ursinus: Chacma baboon

......

......
enrichment

Dorothy Fragaszy

Neuroscience and Behavior Program

University of Georgia

Capuchin 

Monkeys

for nonhuman primates
......



Capuchin Monkeys

......

Capuchin Monkeys

Background

Habitat	

Flexibility, opportunism, and adaptability are the hallmarks of capuchin success. These monkeys occupy virtually every type of Neotropical forest, including 

humid and dry tropical forests, swamp forests, seasonally flooded forests, mangrove forests, and gallery forests, as well as dry, deciduous forests where rainfall 

is absent for five to six months of the year. They range from sea level forest to 

cloud forest up to 2700 meters above sea level. Capuchins are mostly seen in the 

middle layers of the forest, but will use all levels from the canopy to the understory, going to the ground to drink, forage or travel.

Physical Features	

Capuchin monkeys weigh from six to 12 pounds and can live for more than 50 

years. They are physically different from other New World Monkeys (platyrrhines) in that they have robust jaw and dental structures, large brains in relation 

to their body size, and moderately prehensile tails. Additionally, their hands have 

strong grips, a degree of opposition of the thumb to index finger, and somewhat 

independent finger movements. Taken together, these features afford capuchins 

a wide range of locomotor and foraging actions.

Behavior

Capuchins are active monkeys, agile at climbing and leaping. They use their 

hands and mouths to explore objects and surfaces, often destroying them in the 

process. More than other monkeys, capuchins act on their world through coordinated actions of hands, mouth, feet, and tail. They touch, handle, rub, bite, 

pull, push and pound objects as they explore them and manage to undo latches, 

untie ropes, unsnap hooks, and unscrew bolts. 
Capuchin Monkeys

......



Endowed with unusual tendencies to combine objects 

and string together sequences 

of actions with objects, capuchins can, for example, successfully order a set of nesting 

cups. They can use their bodies in innovative ways, such 

as holding multiple cups with 

their hands and feet while 

working with them.

Capuchin monkeys’ memory 

and visual perception are 

similar to those of other nonhuman primates. They travel 

efficiently through familiar 

spaces from one location to 

another and they can use 

landmarks to locate objects 

they cannot see. They have 

good memories for significant 

events, and they perceive objects, object movements, and surfaces in much the 

same way as humans do. 

 

Capuchins are like other monkeys in that they can recognize an abstract relation 

among objects (e.g., sorting objects by size). Capuchins also can recognize two 

relations at the same time and use them in a nested or hierarchical fashion, such 

as sorting pictures by shape and sorting pictures of a given shape by size. 

 

It is important to note that captive monkeys cannot solve everyday problems 

that wild monkeys can without extensive practice. Individual experience and immediate context powerfully affect capuchins’ problem-solving skills and exploratory activities.

Capuchin monkeys express interest in other animals (including human companions) by looking at them, making facial expressions and vocalizing in specific 

ways to express different emotions, and touching them. Young monkeys cling 

Cebus mother and infant (photo by D. Fragaszy).
......



Capuchin Monkeys

to their companions. Adults occasionally groom their companions when they 

feel comfortable and relaxed, using hands and tongues to touch the skin or hair. 

They are also quite playful, especially young monkeys. Capuchins of any age 

tend to be docile, but can become aggressive, even toward human companions, 

if frustrated or frightened. 

Mating and Reproduction

Capuchins reach sexual maturity at four to five years of age. Females have a 

menstrual cycle of 19 – 22 days. Gestation lasts from 22 to 23 weeks, followed 

by 22 weeks without menstruation during nursing if the mother rears the baby, 

or about seven to eight weeks without menstruation if she loses the baby. Infertility while nursing lasts months longer, even after menstrual cycling resumes.

 

Female tufted capuchins (Cebus apella) display their interest in mating using a 

rich and varied behavioral repertoire consisting of facial expressions, vocalizations, gestures, and body postures. In general, the female actively follows a target 

male, which, in most cases, is the dominant male in her group. She directs most 

if not all of her solicitations toward this target male. Initially (for hours and/or 

days), the sought-after male does not reciprocate and tends to avoid the female 

by leaving as soon as she approaches him. Later, the target male starts to respond 

to the female’s solicitations with behaviors similar to hers. At this point, mutual 

sexual interest becomes evident and mating occurs. Females of other species of 

capuchins express their interest in mating less overtly. In these species, solicitations of the female by the male may be more obvious than the female’s solicitations of the male. 

Social World

Capuchin monkeys in the wild live in groups throughout their lives. Males, 

females, and immature animals travel, feed, and sleep near one another every 

day. If a monkey loses sight of its group, it calls loudly and searches actively to 

find the group again. In captivity, capuchin monkeys live compatibly in pairs 

or groups, but they do not live happily alone. Spending any amount of time by 

themselves, without familiar companions, is a hardship for capuchin monkeys. 

Capuchins can live compatibly with other species, for example, squirrel monkeys. 

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Capuchin Monkeys

......



It is easiest to place capuchins in groups when they are young (three years old or 

less). Groups may range from pairs to two dozen or more animals, of mixed ages 

and sexes. Adults can live together in pairs compatibly, and pairs can be formed 

when animals are adults. Both male and female same-sex pairs are compatible, 

as are opposite-sex pairs. However, in the case of male-female pairs, one should 

make sure that the male does not monopolize food or other resources by virtue 

of his greater size and strength. 

Introducing adults to each other as pairs or one adult into an existing group 

should be done with careful supervision, because the monkeys may injure one 

another through fighting. Introducing an adult male to a group with a resident 

adult male is not advised. Allowing monkeys to get to know one another in a 

space where one can escape or hide from the other until they are comfortable 

together makes the introduction process safer. For example, one can place the 

newly introduced individual in visual contact with the group but in a separate 

cage for several days. The new individual can be placed closer to the group in a 

gradual manner. If all individuals behave calmly at this point, the newcomer’s 

cage can be placed next to the group’s cage, permitting some physical contact 

through wire mesh, for example. When the newcomer is not threatened by 

group members, open a doorway between the two. Permit the newcomer to 

enter the group voluntarily, and leave the release cage in place for a period of 

days so that the newcomer can return to it (i.e., escape from the group) if need 

be. There is no certain way to prevent fighting between members of a group and 

a newcomer, so all introductions must be carefully monitored.

Physical World

Capuchin monkeys in the wild spend most of their time in trees. They spend 

about half of their waking hours foraging, eating a wide variety of plant and 

animal foods. In captivity, providing opportunities to travel and rest above the 

ground promotes healthful exercise and hygiene. Providing perches at two or 

more heights allows capuchins to move around in a way that is natural for them. 

In general, the vertical dimension appears more important to these monkeys’ use 

of space than the horizontal dimension. 

Capuchin monkeys benefit from additional opportunities for manual activities 

similar to those used in foraging, including manipulative puzzles and objects to 

......
......



Capuchin Monkeys

handle and tear apart. 

Supplying a variety of 

objects, such as soft 

plastic items or cardboard, on a regular basis promotes healthful 

manual activity. Provision of these items 

must be monitored 

to ensure that gastrointestinal obstruction does not result. 

Providing a variety of 

foods, including different kinds of fruits 

and dairy products in 

addition to a commercial pelleted chow, 

is another element of 

good physical care. 

Fruits, seeds, nuts and 

eggs can be provided 

whole or minimally 

processed; cracking, peeling, separating, and otherwise processing food is 

healthful activity for capuchins, so long as they have the teeth and fingers to 

achieve this. Foods, such as peanut butter and honey, can be hidden in sections 

of a PVC pipe or a box with holes, and the monkeys will use straw or sticks to 

retrieve it. Monkeys new to these tasks may take some time to figure out how to 

solve these problems. Caregivers can provide “hints,” such as placing the stick 

into the tube, to help them learn. It should be noted, however, that food treats 

should not be fed in such quantities to discourage the animals from eating their 

nutritionally balanced diet.

As suggested by the wide variety of habitats in which they live, capuchin monkeys are fairly hardy with respect to temperature and humidity, although they 

cannot cope with freezing temperatures. Monkeys that are accustomed to a narrow range of temperatures and humidity should be introduced gradually to new 

conditions to give them time to acclimate. It should not be assumed that animals will spontaneously seek out heated indoor spaces when the outdoor temWhite-fronted capuchin (Cebus albifrons) resting on a log

(photo by D. Fragaszy).
Capuchin Monkeys

......



perature falls, especially if they have just arrived in new housing. Particularly if 

the ambient temperature falls below 68 degrees Fahrenheit, perches and shelves 

should be constructed of materials that do not conduct heat quickly. Polyvinyl 

chloride (PVC) and wood, for example, do not conduct heat as quickly as metal. 

If outdoor temperatures drop below 45 degrees Fahrenheit, capuchins need 

access to a heated indoor enclosure. Optimum temperature ranges vary among 

the different species, but range from approximately 65-85 degrees Fahrenheit. 

Infants and young juveniles need a heated space at even warmer temperatures. 

Cold monkeys sit in a huddled position with the tail wrapped around the body 

and move less frequently than normal. If there is snow on the ground, monkeys 

may walk in it voluntarily; this can quickly lead to frostbitten fingers and tails, 

which require amputation. 

Capuchins should have enough space to move in a normal manner by walking, 

climbing, and jumping, and places to sit that permit the tail to hang below the 

perch without touching the floor. They prefer to spend most of their time well 

above the floor and flee upward if frightened. However, they will spend much 

time manipulating a loose floor covering, such as straw or wood shavings. Such 

bedding materials provide an attractive focus for activity for captive monkeys 

and enrich the environment in a positive way. 

Capuchin retrieving food items from a pool (photo by D. Fragaszy).
......



Capuchin Monkeys

Capuchins housed in social groups, particularly if the groups are large (i.e., 

10 or more monkeys), should have enclosures with at least two separate compartments, separated by a wall and with one or more connecting doorways or 

tunnels. This arrangement reduces injuries by permitting animals to avoid one 

another, and it makes separating animals simpler for the keeper and less stressful 

for the monkeys. Capuchins in exhibits such as zoos should have an area available to them that is away from the visitors’ view, to allow for occasional privacy. 

Special Cases

There are no particular considerations for older monkeys so long as they are in 

good health. Infants, on the other hand, require more frequent feeding, a more 

easily chewed and digested diet, and an object to which they can cling, such as a 

paint roller attached to a base so that it is stable and can be removed for washCapuchin sitting in a barrel placed off the ground (photo by D. Fragaszy).

......
Capuchin Monkeys

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ing. Even more 

than adults, 

infants need 

constant social 

companionship.

Housing animals individually should be 

avoided. Extra 

provisions for 

manipulative 

activity should 

be provided for monkeys that are temporarily housed individually for medical or 

research reasons, but solitary activities do not substitute for social companionship.

Problem Behaviors

Noticeable changes in posture, movement, and activity level are indicators that 

a monkey may be ill. Capuchin monkeys can develop stereotypical movement 

patterns, such as pacing, and they may perform these more persistently when 

stressed. When captive monkeys persistently make vocalizations known as 

“chucks” that are used in the wild when predators appear, this means that they 

are frightened. Monkeys normally give chucks when strangers or people associated with capture, such as veterinarians, appear. Altering care routines or housing 

arrangements may reduce fear; social companions and alternative activities can 

help capuchin monkeys return to a calmer condition. 

Capuchin monkeys engage in a highly distinctive, self-care behavior, known as 

anointing, in which they rub pungent and sometimes topically irritating plant 

or animal materials on their fur. Captive monkeys may do this with oranges, for 

example. They also rub their bodies with urine, a behavior called urine washing. 

Although these behaviors may appear aberrant, they are, in fact, normal. 

Social group in semi-naturalistic environment (photo by K. Bayne).

......
......



Capuchin Monkeys

Safety Issues

Capuchins do not readily accept physical restraint, such as being held in a 

gloved hand. They will bite if frightened, as during restraint or imminent 

capture, and they have a strong bite. It is best to use a sturdy box with a latching sliding door to transport animals or to train them to participate voluntarily 

(e.g., using a leash and collar). Capuchins can be readily trained using positive 

reinforcement to perform behaviors required for many routine care procedures, 

such as moving from one place to another. Chemical or physical restraint should 

be a last resort only. 

As with all monkeys, handlers should be careful about latching cages securely. 

Capuchins are particularly interested in opening latches; mere springs or harness 

snaps, for example, will not hold them for long. A padlock is more secure. 

Capuchin monkeys are hardy when kept in healthful conditions. They are, 

however, highly susceptible to the common human cold and other respiratory 

illnesses. People suffering from these illnesses should not go near the monkeys. 

Like other monkeys, capuchins also are highly susceptible to measles, chicken 

pox, and other viral diseases common in humans. Capuchins (primarily Cebus 

apella) may be particularly susceptible to Type II diabetes if fed improperly and 

not allowed sufficient physical activity.

Resources

Bayne K, Dexter S, Suomi S. 1991. Ameliorating behavioral pathology in Cebus 

apella monkeys with social housing. Laboratory Primate Newsletter. 30(2):9-12.

Cooper MA, Thompson RK, Bernstein IS, et al. 1997. The integration of 

stranger males into a group of tufted capuchin monkeys (Cebus apella). American 

Journal of Primatology 42:10 (Abstract).

Fragaszy D, Visalberghi E, Fedigan L. 2004. The Complete Capuchin: The 

Biology of the Genus Cebus. New York: Cambridge University Press.

Hayes SL. 1990. Increasing foraging opportunities for a group of captive 

capuchin monkeys (Cebus capucinus). Laboratory Animal Science 40:515-519.

......

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Capuchin Monkeys

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10

Ludes E, Anderson JR. 1996. Comparison of the behaviour of captive whitefaced capuchin monkeys (Cebus capucinus) in the presence of four kinds of deep 

litter. Applied Animal Behaviour Science 49:293-303.

National Research Council. 1998. The Psychological Well-Being of Nonhuman 

Primates. Washington, DC: National Academy Press.

Nowak R. 1999. Walker’s Primates of the World. Baltimore, MD: The Johns 

Hopkins University Press.

Riviello MC. 1995. The use of a feeding board as an environmental enrichment 

device for tufted capuchin monkeys (Cebus apella). Primate Report 42:23-24 

(Abstract).

Visalberghi E, Anderson JR. 1999. Capuchin Monkeys. In: The UFAW 

Handbook on the Care and Management of Laboratory Animals, Seventh Edition. 

UFAW [Universities Federation for Animal Welfare] (edited by T Poole and P 

English), 601-610. Blackwell Science, Oxford, UK.

Westergaard GC, Fragaszy DM. 1985. Effects of manipulatable objects on the 

activity of captive capuchin monkeys (Cebus apella). Zoo Biology 4:317-327.

Common Names of Capuchins

Cebus albifrons ssp: White-fronted capuchin, Brown-faced capuchin, Ecuadorian 

capuchin, Shock-headed capuchin, Trinidad white-fronted capuchin, Varied 

capuchin, Andean white-fronted capuchin

C. apella ssp: Black-capped capuchin, Guianan brown capuchin, Brown 

capuchin, Tufted capuchin, Hooded capuchin, Large-headed capuchin, 

Margarita Island capuchin, Peruvian tufted capuchin

C. capucinus ssp: White-throated capuchin, White-faced capuchin, Panamanian 

white-throated capuchin, Gorgona white-fronted capuchin

Cebus libidinosus ssp: Bearded capuchin, Tambopata tufted capuchin, Pale 

capuchin, Paraguayan tufted capuchin

C. kaapori: Ka’apor capuchin

C. nigrivittatus ssp: Weeper capuchin, Weeping capuchin, Black-horned 

capuchin, Crested capuchin 

C. olivaceus ssp: Brown weeper capuchin, Chestnut capuchin, Ka’apor capuchin, 

Kakapo capuchin, Wedge-capped capuchin, Weeper capuchin, Weeping 

capuchin

C. xanthosternos: Yellow-breasted capuchin

......
enrichment

Kate Baker, Ph.D.

Tulane National Primate Research Center

Chimpanzees

for nonhuman primates
......



Chimpanzees

......

Chimpanzees

Background

Habitat

In the wild, chimpanzees live in large forested areas, but they may also inhabit 

dry savannah and mosaic habitats of grassland-woodland-forest environments, as 

well as montane forests up to 10,000 feet in elevation. They spend much time in 

trees and may scatter widely over their territory rather than traveling around in 

one large group. 

Physical Features

Chimpanzees weigh up to 200 pounds, though the normal average weight for 

an adult female is 130 pounds and for an adult male is 140 pounds. Chimpanzees may grow to a height of 3 - 5 1/2 feet. Adult males generally are larger than 

females. Reaching their adult size by the time they are 14 to 16 years old, these 

animals can live to be 60 years old, with an average life span of 40 to 45 years. 

Chimpanzees are extremely strong and quick. They are omnivores, eating fruits, 

vegetables, insects and other animals at times. 

Behavior

Chimpanzees have many ways of communicating with each other. Facial expressions, calls, and gestures reflect their relationships with other chimpanzees and 

with people. Understanding these methods of communication is essential for 

having a good relationship with them and staying safe in their presence.

 

Chimpanzees make noisy shows of banging, hooting, rocking back and forth, 

and running, hitting or kicking things as they go. This is called a “display” and 

is normal for them. They do this because they are excited or trying to impress. 
Chimpanzees

......



Displays are common when chimpanzees meet new chimpanzees or people and 

at the arrival of food. Sometimes chimpanzees will throw feces or spit on people 

during these displays. Reacting to such behavior (e.g., jumping away, yelling at 

the chimpanzee) will only encourage it. Walking away slowly or ignoring this 

behavior will discourage it over time. 

 

It is important to recognize that there is a hierarchical priority among chimpanzees for access to food that must be considered during feeding, foraging activities 

and access to enrichment foraging devices. Chimpanzees may show their lower 

status to another chimpanzee by bowing or grunting.

Chimpanzees make different sounds and expressions depending on what they 

are doing and trying to communicate. They may make a series of small grunts 

as they eat and a call that sounds like “WHA-OOO” as a warning of possible 

danger. If frightened or nervous, they will show their teeth and gums. Alternately, when playful, chimpanzees may show a wide-open mouth with the top teeth 

covered. They also make snorting or panting sounds when they play. Other 

gestures/vocalizations include an “open mouth grimace” (to express fear), squeal 

and pant-hoot (to express excitement).

An angry chimpanzee will press its lips together tightly, a warning to stay out of 

reach. Chimpanzees threaten each other by gesturing forward violently with an 

arm or wrist, as if shooing another away.

 

Friendly contact is extremely important to them. Chimpanzees will spend long 

periods of time grooming each other or simply sitting in contact. Many chimpanzees are very playful as well, tickling, chasing, wrestling, and gnawing on 

each other.

Chimps at play 

(photo by S. Lambeth).
......



Chimpanzees

Mating and 

Reproduction

Puberty starts at 

about seven years of 

age. Male chimps 

can breed as young as 

seven to eight years of 

age. Female chimps 

in captivity can get 

pregnant as young 

as nine years of age. 

Because menopause 

is not documented in 

chimpanzees, females 

can remain fertile 

for decades. Females in estrus, which happens every four to six weeks, have 

prominent swelling of the pink genital skin that usually lasts two weeks. When 

in estrus, they may mate many times a day if housed with a male. There is no 

breeding season. Chimpanzee pregnancy lasts 33 to 34 weeks. Newborns cannot 

hold on to their mothers, who need to support them so they can nurse. Infants 

should be able to cling to their mothers without help after a few days. After 

several months, infants may start riding on their mothers’ backs rather than 

abdomens. Infants will nurse until they are about three years old. 

Social World

In the wild, chimpanzees live in large social groups. These groups share a territory and are hostile to other groups. Typically, a wild chimpanzee will know many 

other individuals, visiting with them on a regular basis. While wild chimpanzees 

often spend part of the day alone, they are naturally social animals for whom 

constant solitude is a hardship. 

In captivity, housing chimpanzees in social groups is essential to their quality 

of life. Young animals learn many lessons from the other, older animals in the 

group.

Chimps grooming (photo by K. Baker).

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Chimpanzees

......



However, it is not always easy to form and maintain such groups. One must take 

great care in introducing unfamiliar chimpanzees to each other, keeping in mind 

that they are hostile to strangers in the wild. Several steps can be taken to make 

introductions go more smoothly. First, it is a good idea to let chimpanzees see 

but not touch each other for a short amount of time. Long periods of seeing but 

not touching, however, may make them more hostile to each other. Ideally, giving them a day or two of seeing each other should be followed by letting them 

touch each other but not enter each others’ enclosure. This gives them a chance 

to meet each other and establish dominance more safely than suddenly putting 

them together in the same enclosure as complete strangers. 

Some fighting during introductions is not unusual. A few fights, even those that 

cause small wounds, are not necessarily cause for separation. The animals need 

time to establish a hierarchy. It is important to give them time to work this out 

and reconcile after fights, which they often do. However, if fights become more 

frequent or more severe over time, then the individuals may indeed be incompatible.

Tolerance of young animals by adult males (photo by M. Bloomsmith).
......



Chimpanzees

Newly-introduced chimpanzees 

should be watched carefully for 

at least a week. It is important 

to keep things quiet and calm 

around them, since they will be 

more likely to attack each other 

when there is noise, commotion or a stranger nearby. If 

several chimpanzees are to be 

introduced into one group, it 

is best to introduce different 

combinations of pairs together 

over several days before putting everyone together. If a male and female are introduced to each other, the introduction will go more smoothly during the time 

of month when the female has a sexual swelling. The riskiest social introductions 

involve males meeting each other, or chimpanzees that were housed alone for 

long periods of time.

Even chimpanzees that know each other well may fight on occasion. Fights 

often look and sound worse than they are. Trying to stop a fight, for example, by 

spraying chimpanzees with water, will do no good and may make things worse. 

Separating them and keeping them alone for a while is also a bad idea. They 

will remember their dispute and may fight even worse once they are reunited. It 

is best to let fights 

take their course 

unless they are likely 

to cause significant 

harm or are lifethreatening. It is 

important to avoid 

unnecessary separations of chimpanzee 

groups, since they 

will often fight 

during reunions. 

Subtle changes in 

body movements 

and posture often 

Social curiosity/learning (photo courtesy of S. Ross).

This enclosure provides multiple objects for enrichment to minimize 

aggression (photo by K. Baker).
Chimpanzees

......



signal that an aggressive encounter is about to take place, especially between 

males. The male may exhibit slow swaying movements, raising of hackles and an 

increase in the volume of hooting.

While it would be difficult to eliminate all fighting, it is a good idea to avoid 

giving chimpanzees things to fight over, such as toys and food. Minimizing competition for food can reduce the number of fights. For example, giving a group 

one watermelon is much more likely to cause fighting than scattering pieces of 

watermelon all over the enclosure. Similarly, it is a better idea to give a group of 

chimpanzees several boxes to play with rather than one big piece of cardboard.

In captivity, chimpanzees benefit from social interaction with people (conducted 

safely), particularly when they lack companions of their own species. Many 

captive chimpanzees will want to groom humans, be groomed, or play chase 

or tickle games. While friendly relationships with people can be essential to 

chimpanzees with few or no companions, there are significant, potentially lethal, 

physical risks to people associated with such interactions (e.g., bite wounds, 

scratches, bruising, and possibly the transmission of infectious diseases), and the 

best approach in most circumstances is the provision of another chimpanzee. 

Human-chimpanzee interactions that permit limited contact in a safe manner can be achieved

(photo by K. Baker).
......



Chimpanzees

Physical World

In the wild, chimpanzees spend much time in the trees. Thus, in captivity, they 

need climbing structures and comfortable places to sit up high. Fire hose, strong 

chain, cargo nets, perches, and tire swings all can be used for this purpose. If 

rope or chain is used, it should be thick and taut enough to prevent loop-forming and possible strangulation. Structures that provide shade and privacy, such 

as concrete culverts and small lengths of solid fencing, help avoid overheating 

in hot weather. They also give chimpanzees solitude if they want it and help to 

reduce aggression by providing visual barriers. Movable structures such as empty 

plastic barrels are favored resting spots, and chimpanzees can move them to 

where they want to sit. Barrels cut in half are popular “toys” for chimpanzees. 

Enclosures that include an outdoor area will provide the opportunity for chimpanzees to engage in the normal variety of behaviors typical for the species. Letting them choose whether to be inside or outside is important, since it appears 

that chimpanzees like to make some decisions for themselves.

Wild chimpanzees build nests out of branches and leaves. When caged, chimpanzees will benefit greatly from having nesting material such as blankets, straw 

or hay (though these materials may be allergenic), etc. Tree branches may be 

used, although be aware that some common trees, such as fruit trees, magnolia, some oaks, 

and hickory are 

toxic. Care also 

must be taken to 

avoid providing 

branches that are 

long enough for 

chimpanzees to 

use them to escape 

from open-top 

enclosures. In large 

enclosures, entire 

uprooted trees have 

been provided for 

enrichment. An example of a nest built by a chimpanzee in captivity

(photo by K. Baker).

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Chimpanzees

......



A food puzzle being used by a chimpanzee (photo by K. Bayne).

One relatively easy way to keep life interesting for chimpanzees is to give them a 

large variety of healthy foods over time. While the basis of the diet (e.g., commercially prepared feed) should be nutritionally complete, fruits and vegetables, 

breakfast cereal, eggs, yogurt and other healthful snacks are good supplements. 

These are best provided as frequent, small feedings, rather than in large quantities once a day. While it is important not to overload chimpanzees on food 

treats, a sprinkling of “snacks” can help to prevent boredom and abnormal behaviors, particularly if the animals have to move around the enclosure to obtain 

the snacks (i.e., work for them). In the wild, chimpanzees rarely go very long 

without eating, regularly snacking on ripe fruits and leaves. Also, the more timeconsuming the food is to find and eat, the better it is for the chimpanzee. Foods 

such as unshucked raw ears of corn and frozen, finely chopped and widely scattered foods help keep chimpanzees occupied. Requiring chimpanzees to climb 

by placing frozen items on wire mesh ceilings or elsewhere presents a challenge 

for them and provides exercise.

Another easy way to enrich the chimpanzee’s environment is to provide large, 

sturdy toys that are sold for children, large dogs and zoo animals. Many vendors 

sell toys at a lower price than at the local pet store. Rotating toys will maintain 

the interest of the animals. Providing climbing structures is especially important.

Chimpanzees like to destroy things. Giving them items they can safely wreck, 

many of which are free or very inexpensive, is a widely used way of entertaining 

them. A cardboard box can be played in, squashed, ripped, chewed, and finally 

used for nesting material. Long sheets of butcher paper are very entertaining 

(butcher paper is easier on drains and easier to clean up than newspaper). An 

empty plastic soda or milk bottle, perhaps containing a small food treat, pro-
......



Chimpanzees

vides a good source of entertainment. Such objects, however, must 

be checked frequently and removed 

when they become damaged. Because small objects can lodge in the 

throat or other part of the intestinal 

tract, objects introduced for enrichment purposes must be monitored 

to ensure animal safety.

Chimpanzees are extremely intelligent and will benefit from problemsolving and other mental activities. 

Inexpensive puzzles and projects can 

be made out of materials available 

at a home-improvement store. Even 

something as simple as a piece of polyvinyl chloride (PVC) pipe smeared on the 

inside with peanut butter, along with a stick or narrower piece of pipe to insert 

to get at the food, makes a pleasant diversion for chimpanzees. A PVC pipe 

drilled with a few finger holes and containing a frozen banana is another easy 

idea. Other safe and effective puzzles are described on the internet (see online 

resources listed at the end of the chapter.). Many chimpanzees enjoy finger 

painting or drawing with nontoxic crayons. Finally, training is great stimulation 

for the smart mind of a chimpanzee and is fun for people as well.

Chimpanzees should be housed in an environment that gives them adequate ventilation, shade during hot days, and heat 

during cold days. Providing a fresh flow 

of air is recommended if the temperature 

gets as high as 90° F. They may enjoy 

the flow of water from a sprinkler placed 

outside their enclosure so that part (but 

not all) of their housing area receives 

some cooling. Chimpanzees should 

never be exposed to temperatures below 

50° F. Even at higher temperatures than 

this, they will need supplemental heat. 

A chimpanzee manipulates objects provided for 

enrichment purposes (photo courtesy of S. Ross). As 

always, caution must be exercised to ensure animals 

are not harmed by the enrichment devices.

A hand-held mirror provides enrichment to 

chimpanzees, who are interested in their own 

reflections (photo by K. Baker).
Chimpanzees

......

10

Special Cases

Age-related Considerations 

Chimpanzees can live for more than forty years in captivity. During the course 

of their long lifespan, their needs change. Infancy is a critical time behaviorally 

and will determine whether the animal grows up to be behaviorally normal or 

have life-long behavior problems. Infants should remain with their mothers as 

long as possible. In the wild, young chimpanzees need their mothers’ care until 

they are about five years old. Separation from the mother before the age of one 

or two will result in an adult that may have trouble getting along with other 

chimpanzees, show a lot of abnormal behavior, and not cope well with changes 

and stressors. If infants are reared apart from their mothers, exposure to other 

infant chimpanzees is critical. 

At the other end of the lifespan, the needs of chimpanzees change as well. 

Regular health care through a qualified veterinarian, important throughout a 

chimpanzee’s life, is critical in old age. Aged chimpanzees experience many of 

the same problems that old people do, including bone loss, joint problems, and 

undesirable weight changes. Obesity increases the risks of cardiovascular disease and other health problems. Comfortable enclosures with bedding become 

particularly important. Aged chimpanzees can be expected to be less active, but 

their needs for a social life and stimulating environment do not diminish.

Individual Housing 

A chimpanzee that must be individually caged due to health problems, severe 

social problems, the unavailability of social partners, or research reasons will 

require extra care in the form of enrichment and human interaction. While a 

chimpanzee may have to be individually caged, it should not be kept alone in 

a room, unless it is necessary to control the spread of disease. Rather, it should 

have visual and auditory contact with chimpanzees in other cages. 

All the enrichment ideas mentioned above are especially critical for the singly 

caged chimpanzee. Providing a more interesting diet is another way of reducing 

boredom, but the fact that individual chimpanzees tend to be inactive means 

that a lot of attention has to be paid to food quantities and calories to avoid 

obesity. Freezing fruits and vegetables, or scattering low-calorie items in straw 

are ways of increasing feeding time without adding too many calories. Singly 

......
......

11

Chimpanzees

caged chimpanzees will make a lot of use of toys and videotapes or live-feed of 

other chimpanzees (particularly familiar individuals). Very sturdy hand-held 

mirrors also may provide entertainment. Providing new structures or changing 

the installation of structures from time to time (e.g., suspending fire hoses in a 

new position) is another way to vary their environment and induce exploration 

behaviors. Access to the outside benefits all chimpanzees and provides a great 

deal of stimulation to singly caged chimpanzees.

Problem Behaviors

Captive chimpanzees may develop bad habits, including strange behaviors not 

normally seen in the wild. Some of these behaviors are very harmful to the 

animal’s physical health. The most serious problem behavior is self-biting and 

self-wounding, collectively referred to as self-injurious behaviors (SIB). Little 

can be done about this behavior once the chimpanzee is in the habit of hurting 

itself, although there is some evidence with other primate species that pharmacologic intervention may control SIB. Such chimpanzees need intensive veterinary 

care and a strong behavioral management program for life. 

Other behavioral problems that are difficult to eliminate because they develop 

early in life can be reduced by enriching the chimpanzee’s environment. Examples of these abnormal behaviors include rocking, thumb sucking, eye or ear 

poking, hair plucking, or odd and pointless motions or postures. Some of the 

easier abnormal behaviors to eliminate involve strange “eating” habits, such as 

consuming regurgitated food and feces. Increasing the number of small meals 

and providing bedding can help to eliminate such behaviors. Adding climbing 

structures and playthings also can be tried. Positive reinforcement training can 

be used not only to improve the quality of the chimpanzee’s life but to train for 

behaviors that replace the problem behavior.

Some problem behaviors may be due to physical rather than psychological 

causes. A sudden change in behavior or the development of a new abnormal behavior calls for a medical evaluation. For example, diarrhea may be a response to 

psychological stress, in which case changes to the environment might help. On 

the other hand, it could be the result of bacterial or parasitic infection requiring 

treatment.

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Chimpanzees

......

12

No one technique for dealing with problem behavior is foolproof. Each chimpanzee is an individual. A chimpanzee should be watched to determine the 

effectiveness of changes made. Several different approaches may need to be tried 

before a behavior problem improves. Some attempts to fix behavior may backfire 

as well, so familiarity with the individuals and ongoing observation is essential. 

For example, one chimpanzee may be unreasonably frightened of something 

new or different, while another will take to it immediately. Chimpanzees 

may adjust to something new gradually or avoid it forever. In some cases, the 

chimpanzee’s immediate reaction is different from its long-term response. Observe the chimpanzee to see if it makes use of the enrichment, and if it reduces 

or eliminates the behavior problem. It is important to keep a record of what 

changes were made and how the chimpanzee responded. 

Safety Issues

Chimpanzees are fast and strong, so great care must be taken when working 

with them. Chimpanzees that want to be groomed or tickled can press their 

backs or shoulders against enclosure mesh or bars for you; there is no need to 

stick your hand in the enclosure and risk getting bitten or grabbed. Indeed, 

some chimpanzees will appear to invite such contact, only to quickly turn and 

try to bite the person. Furthermore, always keep an eye on where their hands are 

and stay away from their mouths.

Chimpanzees can be extremely unpredictable. They are known to trick people 

into coming within grabbing distance by pretending their arms cannot reach 

out as far as they actually can. If agitated, they may lash out at familiar people to 

whom they have never been aggressive before. 

Chimpanzees can certainly hurt people, and people can inadvertently expose the 

animals to harm. For example, chimpanzees can catch the same illnesses humans 

can, so care should be taken not to expose them to people with colds or the flu. 

Anyone working around chimpanzees should have a tuberculin test every six 

months or other documentation of being tuberculin negative (e.g., chest x-rays). 

An excellent way for people to interact more safely with chimpanzees is to utilize 

a training technique known as positive reinforcement, in which a desired behav-

......
......

13

Chimpanzees

ior is linked to something 

the animal likes. People 

can positively reinforce 

chimpanzees by “catching” 

them doing something 

desirable (e.g., sitting 

down, leaning its shoulder against the enclosure 

barrier near you, etc.), 

and praising or treating 

them with a small food 

reward. By using a specific 

word or gesture when the 

chimpanzee performs the 

desired behavior, people 

can eventually use the 

word or gesture to “ask” 

for the behavior. Because such training takes some level of expertise, one should 

be familiar with positive reinforcement training techniques, both in general and 

specific to chimpanzees, before attempting this procedure.

Chimpanzees can be trained to play with or groom each other or to stop stealing 

each others’ food. Many chimpanzees enjoy learning a variety of commands 

(e.g., show me your shoulder, bring me your toy). While it may start as a game 

just to stimulate their minds and have fun, these commands may come in handy 

unexpectedly. For example, it may be possible to command an injured animal 

to present the body part for inspection. It may also form the basis for training 

chimpanzees to cooperate with procedures that would otherwise be very stressful 

for chimpanzees and people alike. 

Like all wild animals, chimpanzees will need to be restrained occasionally for 

clinical care and transport. However, chimpanzees can be trained to cooperate 

with procedures. Training can be used to make procedures such as receiving 

an injection or moving from the home cage to a transfer cage less frightening 

and stressful for the animal. A chimpanzee trained to cooperate with medical 

procedures such as heart rate or temperature measurement may not need to be 

anesthetized for those procedures. 

Through the use of positive reinforcement training, a chimpanzee 

cooperates with receiving an injection (photo by K. Baker).
Chimpanzees

......

14

Positive reinforcement training should be employed whenever possible and will 

result in a positive relationship between chimpanzees and their caregivers. Letting chimpanzees know what is needed of them, and giving them a chance to 

cooperate, gives them some control over their lives. Threatening or punishing 

chimpanzees, on the other hand, will encourage them to do unpleasant things to 

people (spitting, throwing feces) and resist their caregivers at every opportunity.

Resources

Brent L (Ed). 1997. The Care and Management of Captive Chimpanzees. American Society 

of Primatologists. 252pp.

Maki S, Bloomsmith M. 1989. Uprooted trees facilitate the psychological well-being 

of captive chimpanzees. Zoo Biol 8:79-87.

Reinhardt V. 1997. The Wisconsin Gnawing Stick. Animal Welfare Information Center 

(AWIC) Newsletter 7(3-4), 11-12.

Chimpanzees in the wild and in captivity: 

http://www.discoverchimpanzees.org/chimps/chimps.php (Jane Goodall Institute Center 

for Primate Studies)

http://www.oaklandzoo.org/atoz/azchimp.html (Oakland Zoo)

http://www.honoluluzoo.org/chimpanzee.htm (Honolulu Zoo)

Enrichment:

http://www.arkanimals.com/ark/e_enrichment_101.html

http://www.awionline.org 

Training:

http://www.awionline.org/Lab_animals/biblio/jo-6.htm

http://behavior.org/animals/index.cfm?page=http%3A//behavior.org/animals/animals_chimps.cfm

http://www.nal.usda.gov/awic/pubs/primates/4n4laule.htm

A useful listserv: ask questions and get answers, exchange ideas: 

http://pin.primate.wisc.edu/infoserv/forums/pef/

http://www.primate.wisc.edu/mailman/listinfo/pef

Primate Organizations:

American Society of Primatologists, www.asp.org 

Association of Primate Veterinarians, www.primatevets.org 

International Primatological Society, http://pin.primate.wisc.edu/ips/ 

Common Names of Chimpanzees

Pan troglodytes

P. troglodytes troglodytes: Tschego

P. troglodytes verus: Common or masked chimpanzee

P.troglodytes schweinfurthii: Eastern or Long-haired chimpanzee

Pan paniscus: Pygmy chimpanzee, Bonobo, Lesser chimpanzee

......

......
enrichment

Kathryn Bayne, M.S., Ph.D., D.V.M., DACLAM, CAAB

AAALAC International

Macaques

for nonhuman primates
......



Macaques

Background

Habitat

The macaques represent a collection of approximately 20 species of monkeys, 

most of which are found in Asia. They occupy a wide geographic range that is 

considered second only to man in its extent. In this range, the habitat occupied 

by macaques varies from near desert to rainforest, and from sea level to snowy 

mountain tops. Some macaques spend the majority of their time in trees, while 

others are predominantly ground-dwellers. Many live in close proximity to 

human beings; the rhesus monkey is sacred to Hindus and is often found near 

temples in India and Nepal.

 

Physical Features 

In general, the macaques have a 

medium-sized body, with a stocky 

build. Animals belonging to the 

smallest species weigh approximately 

13 pounds, while representatives of 

the largest species weigh an average of 40 pounds. Tail length varies 

among the different species. All 

macaques have long, sharp canine 

teeth and finger nails that can pose 

a risk to human handlers through either bite or scratch wounds. They also have 

cheek pouches and a fully opposable thumb. The opposable thumb gives these 

animals the ability to manipulate objects (e.g., cage latches) with great precision. 

They feed on both animal and vegetable resources and have a highly varied diet. 

Macaques are primarily active during the daylight hours, and most species sleep 

in trees at night. 

Rhesus (Macaca mulatta) monkey with cheek 

pouches full of food (photo courtesy of K. Bayne).

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Macaques
Macaques

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Behavior 

As a rule, the macaques are social animals, living in groups of multiple males 

and females; the sex ratio typically reflects more females than males in a group. 

Even for the same species, group size tends to be smaller when the home range 

size is also smaller (e.g., when constrained by human activities). Within these 

groups, individuals are ranked according to dominance (hierarchies), with the 

higher ranking animals doing more of the successful breeding and having first 

access to food and other desirable resources. Often it is the rank of the mother, 

rather than the father, that determines the rank of offspring. Young males may 

be evicted from their birth group as they approach puberty, forming temporary 

“bachelor” groups until they join a new group. Wounding of animals can occur 

when challenges for dominance occur.

Because these animals 

rely in large part on visual 

communication, they use 

a number of facial signals, 

often accompanied by vocalizations, to threaten or 

to make friendly overtures. 

Threat displays include 

opening the mouth in the 

shape of an “O”, a direct 

stare, raising the eyebrows 

quickly and repeatedly, 

flapping the ears, a jerky head-bob, shaking an object in their environment such 

as a tree branch or cage door, slapping the ground, or charging with intent to 

fight. Occasionally, a lack of compatibility between animals can be detected 

simply by the increased physical distance maintained between them. Behavioral 

indicators of compatibility between animals include social grooming, lip-smacking, and sitting in close proximity. Food sharing has also been used to assess 

compatibility between pairs of animals.

Social grooming is an integral part of forming affiliations

(photo courtesy of K. Rasmussen).
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Macaques

Mating and 

Reproduction

The reproductive 

cycle of macaques 

is characterized by a 

seasonal estrus period, 

with menstrual cycles 

occurring throughout 

the year. Females have 

been reported to begin 

cycling as early as approximately 1.5 years, 

although a more typical 

age is 2.5 years. Most 

species of macaques 

exhibit swelling and 

reddening of the skin 

of the rump, perineum, 

and occasionally arms, 

legs and face (referred 

to as “sex skin”). The 

swelling and reddening becomes more 

pronounced from 

beginning to end of the 

menstrual cycle. Exceptions to this are bonnet macaques and toque monkeys, 

who do not have marked sex skin. Menopause occurs in the macaques, with the 

number of menstrual cycles decreasing each year when the animal reaches her 

third decade of life. 

In general, the female actively solicits mating by the male (again, the bonnet macaque is an exception to this). Usually, the dominant males in the group breed 

the females more often, although less dominant males in a group have been 

reported to breed and reproduce successfully. The rhesus monkey’s gestation 

period is between five and six months. The infant is quite dependent upon the 

mother, and the current preference is to leave the infant with its mother until 

approximately one year of age to help ensure adequate development of social, 

particularly maternal, skills by the developing infant.

Social defense of territory (photo courtesy of K.Rasmussen).
Macaques

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Social World

Because of the intrinsic social nature of macaques, pair or group housing of 

compatible animals is extremely important. It is well-known that raising a macaque alone, without the company of other macaques of the same species, will 

result in that animal expressing a pattern of abnormal behaviors that can become 

self-destructive. Even the 

behavior profiles of adult 

animals housed alone can 

degenerate into inciting 

these abnormal behaviors, which may include 

repeated pacing, circling, 

or somersaulting; hyper-aggression; depression; and self-injurious 

behavior, including hair 

plucking or self-biting. 

(See section on “Problem 

Behaviors”). 

While group or pair 

housing is strongly 

recommended for macaques, care should be 

taken in doing so. Since 

these primates establish dominance hierarchies and space is limited in captivity, 

the macaque wishing to flee the dominant animal has no place to fully escape. 

This can result in unresolved, increased aggression between the animals as well 

as wounding (and possibly killing) of one or more animals. 

Larger groups of animals that previously have been living in smaller stable 

cohorts should not be formed, because this will increase fighting between the 

smaller, pre-established groups. A better approach is to place unfamiliar animals 

together in a new enclosure at the same time. In this way, coalitions have not 

already been formed, and each macaque must establish its own place in the hierarchy without support from other animals.

Evidence of hair-plucking behavior, a type of self-injurious 

behavior (SIB) on the leg of this macaque

(photo courtesy of K. Bayne).

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Macaques

One approach to forming pairs of macaques is provided at the end of this chapter. The key steps include the following: 

• Introducing the animals into an area that they do not consider as their 

territory

• Assessing facial expressions, postures and physical distance between the 

animals 

• Proceeding slowly in forming pairs

• Planning ahead to have a way of separating animals should the fighting 

become intense (e.g., a panel to slide between cages, use of water, etc.)

• Ensuring the safety of people performing the animal introductions 

• Providing ongoing 

monitoring 

of animal 

interactions, 

because animal 

relationships can 

change over time

Using the natural 

social structure of the 

macaques will assist in 

forming compatible 

pairs or groups of monkeys. For example, 

because macaques will form bachelor 

troops, often males can be pair-housed 

successfully. Successful pairings of a young 

macaque with an older animal (so that the 

dominance hierarchy is clear and fighting is 

minimized) also have been reported. 

Offering vulnerable areas of the body to be groomed by another 

animal indicates a degree of trust and affiliation between the animals 

(photo courtesy of K. Bayne).

Providing three-dimensional space in the primary 

enclosure, using Primahedrons®

(photo courtesy of K. Bayne).
Macaques

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Physical World

Housing 

Macaques have been housed successfully in a variety of types of housing, 

including island environments, corrals, corn cribs, indoor-outdoor runs, pens 

and cages. Regardless of the enclosure design or size, it must be sturdy enough 

to withstand being shaken and chewed on by its inhabitants. Because of the 

animals’ tendency to flee upward when escaping a perceived threat, they benefit 

from perches, shelves or other structures that increase the three-dimensional 

space of the enclosure. Generally, older macaques prefer a non-moving shelf or 

perch, while the younger ones will readily use swings. Because macaques can 

strangle on lengths of chain, swings should be short in length and/or constructed of materials that cannot loop around the neck, such as flexible polyvinyl chloride (PVC) tubing. Similarly, ropes can be picked apart or chewed on, and this 

may result in a gastric obstruction. Thus, in most cases, ropes of cotton, sisal or 

jute should be avoided.

In general, macaques should not 

be exposed to cold or wet weather 

without a method for them to 

conserve body heat. Japanese 

macaques living in the snowy 

mountains of Japan manage to 

stay warm by soaking in natural 

hot springs. A number of captive macaques, however, have lost 

parts of their tails or one or more 

digits to frostbite. This problem can be reduced or prevented by providing them 

with supplemental heating or a shelter. 

During conditions of high heat and humidity, macaques may overheat if they 

undergo a physical stress, such as being chased around an enclosure. Providing 

macaques with a shallow and indestructible pool in which to swim and cool off 

can be an asset to macaques housed outdoors in warmer climates. The swimming pool should be shallow, to prevent animals from drowning, and resistant 

to deterioration from chewing. The pool should be cleaned routinely to provide 

animals with good quality water for swimming.

......

A horse water trough, shown here, serves as a swimming 

pool for young macaques (photo courtesy of K. Bayne).
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Macaques

Enrichment

The macaques are curious and intelligent animals. Providing them with opportunities to investigate and explore their environment is enriching for them. 

This can be accomplished by maintaining toys in the animals’ enclosures. Since 

macaques have color vision, the toys (also known as manipulanda) should be 

of different colors; they can also be of different shapes and texture. Because 

the monkeys will chew on these toys, they should be relatively durable, such as 

heavy-duty dog toys. Toys should be removed from the enclosure when they become sufficiently damaged that the primate might swallow or choke on a piece. 

Rotating different toys in the enclosure and removing them periodically will 

help to keep the toys novel and increase the animals’ interest in them.

Flexible PVC tubing 

can be installed in the 

primary enclosure to 

simulate branches for 

swinging (photo courtesy 

of K. Bayne).

A variety of toys used with 

macaques (photo courtesy of K. 

Bayne and S. Dexter).

The damage inflicted on toys after usage 

by macaques. Small remnants can pose 

a choke hazard to the animals (photo 

courtesy of K. Bayne and S. Dexter).
Macaques

......



A very successful way to fulfill these animals’ inclination to explore and investigate 

is to give them the opportunity to forage 

(or search) for food. Since many primates 

will spend up to 70% of their waking 

hours in foraging-related activities, offering captive primates the opportunity to 

engage in this behavior can be important 

in preventing the development of abnormal behaviors. Numerous in-house and 

commercially produced devices are available, including toys that simply 

hold the food item and require the 

monkey to fish for or push it out. 

Also available are containers with 

finger holes or slots through which 

the monkey removes the food item, 

as well as puzzle boards in which 

the monkeys must manipulate the 

food item though a maze before it 

reaches a hole large enough from 

which the food can be retrieved. 

Food may be hidden throughout 

the enclosure to encourage searching behaviors. Food items may also 

be ground up into small pieces 

or pre-purchased as “crumbles” 

and then placed on an Astroturf®

or artificial fleece foraging board. 

The small size of the food particle 

encourages manual dexterity and 

extends the amount of time the animal spends searching for and eating the 

food. Food treats, as enrichment, should not be offered in such quantity that the 

animal ignores its more nutritional daily diet or gains excessive weight. Many 

commercially available food treats come in a variety of flavors and are nutritious. 

Food treats may be dispensed from 

puzzle balls (photo courtesy of K. Bayne 

and S. Dexter).

Wedging food treats inside a Kong® toy is another 

way to extend the animal’s time spent in “foraging” 

(photo courtesy of W. Brandon).
......



Macaques

This animal forages 

for food “crumbles” in 

an artificial shearling 

foraging/grooming board 

(photo courtesy of K. 

Bayne).

Special Cases

Age-related Considerations 

The macaques are long-lived animals, with reports of some animals living in 

captivity over 30 years. This lifespan entails a commitment of considerable duration, with substantial, changing needs of the animal over the course of its life. As 

with other species of primates, the design of the environment should take into 

account the age of the macaque. For example, older monkeys will develop arthritis, limiting their ability to jump onto perches, swing, or otherwise navigate 

their enclosure. Older primates can also have reduced vision capabilities, thus 

further limiting their ability to move around the enclosure and interact with 

other animals or people. 

Conversely, young animals are very active and curious. The enclosure design 

should allow them to express these characteristics without compromising their 

physical safety. Young animals also are particularly sensitive to the effects of 

social deprivation and should be housed with other primates of the same species 

whenever possible.

Individual Housing 

The circumstance in which only one macaque is housed on the premises should 

be avoided. If several macaques are housed individually in cages, they should 

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Macaques

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10

be able to see, hear and smell each other. If possible, individually caged animals 

also should have access to visual barriers in order to avoid being seen by other 

animals, should they so choose. It is recommended that if an animal cannot be 

socially housed, other forms of enrichment (e.g., toys, foraging opportunities) 

should be provided to compensate for the lack of social stimulation.

Susceptibility to Disease

Because of their close genetic relationship to humans, nonhuman primates 

can be susceptible to human diseases. Of particular concern is the exposure of 

macaques to tuberculosis from a human. Tuberculosis is a highly contagious, 

fatal disease in Old World Monkeys. Routine testing of the animals is highly 

recommended. Macaques are also susceptible to measles virus, and will show 

a rash similar to that of people having the disease. Most colonies of macaques 

are vaccinated for measles virus. Because numerous individuals may be assisting 

with the enrichment program (including volunteers), close attention should be 

paid to the possible transmission of diseases from humans to macaques.

Problem Behaviors

The most appropriate behavioral management program houses macaques in 

a sufficiently enriched and safe environment to prevent the development of 

abnormal behaviors. Nevertheless, personnel caring for macaques should be 

adequately trained and able to recognize the occurrence of abnormal behavior in 

macaques. It is important to note that not all macaque species exhibit the same 

types of abnormal behavior or to the same degree. Some abnormal behaviors are 

initially quite subtle in their expression, but over time can become more obvious 

and harder to stop. Abnormal behaviors include repetitive movements, such as 

pacing, circling, rocking, spinning, somersaulting and bouncing. Cage-licking, 

self-clasping, self-sucking, masturbation, “saluting,” and eating feces are some 

other aberrant, repetitive behaviors. Abnormal behaviors in macaques also can 

hurt or injure the animals, as in the case of hair plucking, self-biting and head 

banging. 

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11

Macaques

Abnormal behaviors are an undesirable consequence of captive housing, reflecting an inadequate environment for maintaining the animal. Preventing the 

development of abnormal behaviors is critical, because they are difficult to stop 

once they start. In some cases, socially housing an animal that previously was 

singly housed can decrease the expression of abnormal behaviors, presuming 

that the animals are compatible. Progress has been made in reducing the occurrence of hair-plucking behavior by providing the animal with a fleece covered 

Plexiglas® board or coconut, thereby giving the monkey something else to pluck. 

However, redirection of an abnormal behavior is not a “cure” and should only 

be regarded as a temporary correction. Although occasionally self-biting behavior can be redirected to a toy, recent evidence has shown that some drugs will 

reduce the occurrence of this behavior more reliably. In this case, the veterinarian should be consulted.

Safety Issues

In general, the least amount of restraint necessary to accomplish the task should 

be used when working with macaques. However, because macaques can seriously 

threaten people’s safety, the method of restraint should also ensure the safety of 

both the personnel and the animal. Restraint can be achieved by hand (e.g., with 

younger animals), by the use of various drugs such as ketamine hydrochloride, 

or by the use of equipment such as transport cages, the pole and collar system, 

or tunnels to move animals from one location to another. Macaques can be 

trained to cooperate in a variety of procedures, thus reducing the amount of restraint necessary. Examples include training the animals to move into a transport 

box to be removed temporarily from their home cage or training an animal to 

extend its arm or leg for a blood sample to be withdrawn. Such training is an 

important part of the enrichment program as it gives the animal some control 

over the situation and reduces the stress the animal might otherwise experience 

during basic husbandry and medical procedures in which it was not actively 

cooperating. Appropriate protective equipment, including gloves, mask, eye 

protection, etc., should be worn when working closely with macaques.

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Macaques

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12

In addition, the provision of many 

types of enrichment devices involve 

either attaching the device to the 

cage, reaching into a cage to place the 

enrichment, or entering the primates’ 

enclosure. These can place the individual at risk of being grabbed, bitten, 

or scratched. Macaques are a frequent 

carrier of Herpes B-virus, which is 

asymptomatic in the animals but can 

be fatal to humans. This viral infection can be transmitted from animal 

bites, scratches, splashes, needle 

stick injuries, and other contact with 

mucous membranes or broken skin 

with infected body fluids (e.g., saliva, 

urine) from the monkey. Personnel 

should wear appropriate protective 

equipment, concomitant with the 

potential for exposure.

Resources

National Research Council. 1998. The Psychological Well-Being of Nonhuman 

Primates. Washington, DC: National Academy Press. 

National Research Council. 2003. Occupational Health and Safety in the Care 

and Use of Nonhuman Primates. Washington, DC: National Academy Press.

Nowak R. 1999. Walker’s Primates of the World. Baltimore, MD: The Johns 

Hopkins University Press. 

National Research Council. 1996. Guide for the Care and Use of Laboratory 

Animals. Washington, DC: National Academy Press.

U.S. Department of Agriculture. 1991. Animal Welfare Regulations. Title 9, CFR 

Part 3, Federal Register, Volume 56, No. 32.

http://www.bioserv.com (a company supplying food treats and other 

enrichments)

http://www.ottoenvironmental.com/Default.asp (a company supplying 

enrichment items)

A transfer cage is placed against the door of the 

home cage, which is then opened, to move an 

animal without hand restraint or the use of drugs 

(photo courtesy of S.Dexter).

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......

13

Macaques

http://www.enrichment.org (Web site for “The Shape of Enrichment”)

http://www.awionline.org/Lab_animals/biblio/enrich.htm (a bibliography of 

enrichment articles)

http://www.brown.edu/Research/Primate/ (Web site for Lab Primate Newsletter, 

a publication with behavior and enrichment articles)

http://www.aazk.org/committees/enrichment/comm_enrichment_title.php 

(Web site for the enrichment committee of the American Association of Zoo 

Keepers)

http://www.aphis.usda.gov/ac/eejuly15.html (Web site for the U.S. Department 

of Agriculture’s “Final Report on Environment Enhancement to Promote the 

Psychological Well-Being of Nonhuman Primates”)

Common Names of the Macaques

Macaca arctoides: Stump-tailed macaque, Bear macaque, Brown stump-tailed 

macaque

M. assamensis: Assamese macaque, Assam monkey, Mountain monkey, 

Himalayan Macaque, Montane Rhesus

M. brunnescens: Muna-Butung monkey

M. cyclopis: Taiwan macaque, Taiwanese macaque, Formosan macaque, 

Formosan rock macaque

M. fascicularis: Crab-eating macaque, Cyno, Cynomolgus, Irus monkey, Java 

monkey, Kra (or Kera), Long-tail macaque, Philippine monkey

M. fuscata: Japanese macaque, Snow monkey

M. hecki: Heck’s macaque

M. maura: Moor macaque

M. mulatta: Rhesus monkey

M. nemestrina: Pig-tail macaque, Pigtail macaque, Pig-tailed macaque, Giant 

rhesus

M. nigra: Sulawesi crested macaque, Sulawesi black ape, Celebes black ape, 

Celebes ape, Celebes crested macaque, Black ape

M. nigrescens: Gorontalo macaque

M. ochreata: Sulawesi booted macaque, Booted monkey, Booted macaque

M. pagensis: Mentawai macaque

M. radiata: Bonnet macaque, Bonnet monkey

M. silenus: Lion-tail macaque, Liontail macaque, Lion-tailed macaque, Lionmaned macaque, Wanderoo, Wanderu, Ouanderu

M. sinica: Toque macaque, Toque monkey

M. sylvanus: Barbary ape, Barbary macaque, Gibraltar ape, Gibraltar macaque

M. thibetana: Père David’s stump-tailed macaque, Tibetan stump-tailed 

macaque, Tibet monkey

M. tonkeana: Tonkean macaque

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Macaques

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14

Sample Pair Housing SOP -- Macaques

Pair Housing: Following are descriptions of the five different pair housing combinations and the procedure for pairing each combination. It should be noted 

that on-going, vigilant monitoring is necessary to the successful social housing 

program. As animals mature, their relationship may change, necessitating separation of the animals and identification of new partners.

Juveniles: Two juveniles (three years of age or younger) of the same sex are 

paired together.

Place the animals in an appropriate size cage. Check the animals every hour for the 

first four hours and at least three times per day for the first week.

Adult with Infant or Juvenile: An adult (four years of age or older) of either sex 

is paired with a weaned infant or juvenile (eight months to three years) of either 

sex. 

Adult Females: Two adult females (generally cynomolgus monkeys, four years 

of age or older) are paired together, with their unweaned infants (less than one 

year of age), if applicable.

Adult Male and Female: An adult male (five years of age or older) is paired 

with an adult female (four years of age or older), for either breeding purposes or 

enrichment purposes.

Place the animals in a double cage with a clear Plexiglas® panel between them. 

If there are no signs of aggression after one hour, open the panel. Alternatively, if a 

Grooming-Contact (G-C) bar divider is available, use this first. Check the animals 

at least every hour for the first four hours and at least three times per day for the first 

week. Initially, the animals may be separated at night, until a compatible relationship is established.

Adults Males: Two adult males (four years of age or older) are paired together.

Place the males in a double cage with a clear Plexiglas® panel between them. 

Alternatively, if a G-C bar divider is available, use this first. If there are no signs of 

aggression after twenty-four hours, move the animals to a new double cage (to avoid 

territorial aggression) without a panel. Ensure that the males do not have visual contact with any breeding pairs. Check the animals at least every hour for the first four 

hours and at least four times per day for the first week. Initially, the animals may be 

separated at night, until a compatible relationship is established.

......
enrichment

Jeffrey A. French, Ph.D. & Jeffrey E. Fite, Ph.D.

Callitrichid Research Center

University of Nebraska at Omaha

for nonhuman primates

Marmosets 

 & Tamarins

 (Callitrichids)
......



Marmosets & Tamarins

......

Marmosets & Tamarins

Background

Habitat

In the wild, marmosets and tamarins inhabit diverse habitats, ranging from 

Costa Rica to southern Brazil and Bolivia. They are principally tree-dwelling 

animals.

Physical Features

Marmosets and tamarins belong to the New World primate family Callitrichidae, which is characterized by unique morphological and reproductive traits. 

Callitrichids, among the smallest (.5 to 1.3 lbs.) of the New World primates, 

often are brightly colored monkeys with little, if any, gender differences in body 

size or coloration. 

Other distinguishing morphological 

features of marmosets and tamarins 

include claws instead 

of nails on all digits 

except for the opposable hallux, and two 

molars on either side 

of each jaw.

Cotton-top tamarin (Saguinus oedipus) with nestbox and perches 

(photo by K.Bayne).
Marmosets & Tamarins

......



Behavior

Marmosets and tamarins have rich 

communicative behavioral repertoires 

that help individuals communicate 

within their group and with other 

groups. Chemical communication 

via scent marking is one important 

aspect of callitrichid social and sexual 

behavior. Scent marking increases 

when marmosets and tamarins are 

exposed to unfamiliar animals. Callitrichid primates have specialized 

glands (found in the anogenital, suprapubic, sternal, and perhaps facial 

areas), which produce oily secretions 

that are mixed with urine and deposited on branches and, to a lesser 

degree, other surfaces. These scents contain information on species, subspecies, 

and individual identity, as well as reproductive status, social rank, and the age 

of the marking. Scents are also thought to facilitate reproductive suppression of 

subordinate females in some callitrichid species.

Marmoset (Callithrix geoffroyi ) parents sitting with their infants (photo by H. A. Jensen).

Adult Geoffroy’s marmoset, Callithrix geoffroyi 

(photo by H. A. Jensen).
......



Marmosets & Tamarins

Mating and Reproduction

The social behavior of callitrichids within groups, in many ways, revolves 

around two aspects of callitrichid reproduction: reproductive suppression, which 

prevents subordinate males and females from engaging in sexual behavior, and 

extended residence of offspring in the natal family group. Subordinate females 

and adult-aged daughters living in their natal family group do not typically 

engage in reproductive activity and, in most cases, nonbreeding females are 

endocrinologically suppressed and do not ovulate. Likewise, subordinate males 

and adult-aged sons typically do not engage in sexual behavior. Reproductive 

suppression is known to be lifted from subordinate individuals when a new 

breeding male is introduced and following the death or illness of a breeding 

male or female.

Cooperative care is another important component of callitrichid social life. 

Marmosets and tamarins typically produce fraternal twins that are cared for by 

all group members, including both male and female non-reproductive individuals. This is particularly important because, at birth, litters weigh approximately 

15 – 25 percent of adult body weight. Numerous studies have demonstrated 

that subordinate individuals provide a significant amount of care to infants born 

into the group. Indeed, the breeding male has been shown to participate less in 

carrying behavior when there are multiple helpers (e.g., adult offspring), with 

a concomitant increase in his survivability. The expression of competent caregiving behavior, however, requires experience with infants (either one’s own or 

siblings). It is suggested, then, that individuals remain within their natal groups 

during the rearing of the next one or two litters. 

Social World

The social lives of marmosets and tamarins are unique among primates. Marmosets and tamarins are the only primates known to exhibit a cooperative breeding system, characterized by extended residence of offspring within the family 

group, breeding that is mostly limited to a single breeding pair, and care of 

offspring provided by group members other than the parents.

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Marmosets & Tamarins

......



In captive settings, callitrichid primates are 

commonly housed in 

groups comprised of a 

single breeding adult male 

and female, along with 

the independent (subadult 

and juvenile) and dependent (infant) offspring of 

the breeding pair. Captive groups generally do 

not contain unrelated 

individuals, because social 

groups containing unrelated same-sex individuals are likely to be unstable. Studies of captive and wild 

populations of callitrichid primates, however, have revealed that there is some 

degree of intra-specific variation in social structure that can remain stable over 

long periods of time. In fact, a variety of different social structures have been 

found to result in stable social groups, including the following:

• fathers with offspring

• mothers with offspring

• same- and opposite-sex siblings (note: opposite-sex sibling groups are not 

recommended for cotton-top tamarins)

• same-sex pairs or small groups of unrelated or unfamiliar individuals

• single same-sex or opposite-sex individuals of different species

Intra-group aggression is generally directed toward non-breeding individuals by 

their same-sex sibling or same-sex parent. Displacement, threat behavior, chasing, and minor injuries often precede the eviction of an individual from a social 

group. The victim is easily identified because he/she will often separate from the 

group, show fearful behavior when approached by group members (especially an 

aggressor), and generally remain closer to the floor of the cage than other group 

members. Temporary separation for a period of hours or days may allow an 

individual that was in the process of being evicted to be reintegrated into a social 

group. These aggressive events within families are often triggered by periods of 

fertility in the dominant female, and special care should be taken to monitor 

group relations in the two to three weeks after the birth of infants, when the 

dominant females are likely to be ovulating.

Subadult male marmoset (Callithrix kuhlii ) carrying

infant sibling (photo by C. N. Ross).
......



Marmosets & Tamarins

Introducing an adult male and female is quite easy. Generally, a brief period of 

limited contact through mesh or a “howdy cage,” followed by a brief period of 

close observations once full contact is allowed, is all that is needed. Successfully 

introducing same-sex unrelated individuals or new adults into breeding groups, 

however, often is more difficult. In fact, the likelihood of failure increases with 

the age of the same-sex individuals already present in the group. For these introductions, much longer introduction and observation times are necessary.

Physical World

Housing

An ideal captive environment for callitrichid primates promotes good physical 

health, allows for successful reproduction and rearing of offspring, and facilitates 

the acquisition of skills that the animals would need to survive in the wild. Although there are no clear specifications for optimal habitat size, habitats should 

be large enough, and rich enough, to allow and promote a full range of naturalistic behaviors, social interactions, and locomotion patterns. The general rule for 

callitrichid housing is that no housing is too large. Also, as callitrichids are treedwellers and range up to 10 meters above the ground in their natural habitats, 

vertical space is extremely important. If space is limited, narrow, tall housing is 

preferred to wide, low housing.

Cages often are constructed of wood or polyvinyl chloride (PVC) frames with 

steel or wire mesh. Many zoological parks also are constructing callitrichid housing from textured rockwork with glass or wire fronting. The primary furnishing for callitrichid housing should be natural tree branches and other surfaces 

on which the monkeys can climb, leap, and run. Branches should be arranged 

to provide a network of pathways by which the animals can move about their 

home. Branches are particularly important because marmosets and tamarins 

use these as the normal substrate for scent marking. If natural branches are not 

provided, the monkeys will scent mark on smooth, nonabsorbent substrates, and 

the marks may soil their fur.

Marmoset and tamarin group members sleep huddled together, so a nest box, 

placed high in the cage should be provided. Floors should be covered with wood 

......
Marmosets & Tamarins

......



chips or shredded paper; this provides padding for young animals, which are 

most likely to fall from a branch onto the floor, and it also encourages animals 

to forage through the bedding. Food and water should be made available on a 

feeding platform or in a bowl placed high in the cage in a location that prevents 

contamination by urine and feces. 

Since wild marmosets and tamarins are highly territorial under most conditions, 

visual and auditory contact between different social groups should be limited. 

When multiple groups are housed in close proximity to one another, and when 

overcrowding occurs within social groups, increased aggressive behavior is not 

uncommon. Further, chronic arousal associated with prolonged exposure to 

unfamiliar animals can lead to abortions and infant loss. Visual barriers, and 

sometimes sound absorbing materials, should be used to prevent territorial and 

aggressive displays between groups. 

In light of the important role scent marking plays in social and sexual behavior, 

it is often suggested that husbandry practices maintain a sanitary, but smellintact, environment by sanitizing cages less frequently and/or allowing some 

scent-marked items (e.g., nest box, perch, branches, etc.) to remain unsanitized 

and, thereby, retain their odor. However, some practical experience suggests that 

Golden Lion Tamarin (Leontidius sp.) using a rope crossing between trees (photo by K. Bayne).
......



Marmosets & Tamarins

sanitizing these items 

routinely does not result 

in adverse effects on the 

health or reproductive 

capacity of the animals. 

Regardless, most guidelines allow for the maintenance of scent-marked 

branches in cages for 

periods of several weeks 

to several months.

 

Environmental enrichment items and devices 

also are a necessary part 

of callitrichid housing. Not only do they 

promote the development of behavioral and 

logical skills and mental 

and sensory stimulation, 

but they can prompt 

naturally occurring 

behaviors in the animals. 

The amount, type, and presentation of enrichment should be varied to prevent 

boredom. Foraging devices, artificial gum trees, cardboard boxes and gallon milk 

jugs with large holes cut in them, paper towel and toilet paper, are commonly 

used for enrichment. 

Feeding

Meeting the nutritional needs of callitrichid primates is essential to their health 

and well-being in captivity. The diets of wild marmosets and tamarins include 

tree exudates (sap or gum), fruits, buds and flowers, nectar, insects, and small 

vertebrates. Since proportions vary between and within species, only general nutritional issues will be covered here. However, it is important to avoid over-feeding these animals with food treats such that they do not consume a nutritionally 

balanced diet. Further detailed information can be found in the Callitrichid 

Husbandry Manual. 

Example of basic cage with ladder/swing and polyvinyl chloride 

(PVC) nestbox. Branches can be added for scent-marking

(photo by K.Bayne).
Marmosets & Tamarins

......



Young monkeys begin to beg for and eat solid food between three to five weeks 

of age. Approximately 20 percent of the diet of wild marmosets and tamarins is 

protein. A canned marmoset diet, which is now commercially available, should 

provide the foundation of the diet. New World primate biscuits also should 

be offered, along with an assortment of fresh fruits and vegetables. Two fruits 

and two vegetables should be offered daily. Cooked and uncooked cereals, and 

cooked pasta, are ideal sources of carbohydrates. Treats can include gum arabic, 

marshmallows, raisins, crickets, mealworms, and waxworms. 

In the wild, callitrichids spend nearly 60 percent of their day foraging for food. 

Live food or highly preferred food items hidden in bedding simulates a natural 

situation and provides an additional opportunity for enrichment. A foraging box 

can be easily made by placing highly preferred food items into small holes that 

have been cut into a cardboard box filled with bedding. Callitrichids also enjoy 

food items suspended from branches, and treat cups with lids and peek holes. 

Special Cases

Age-related Considerations

Healthy marmosets and tamarins maintain good abilities to forage and move 

about well into their old age. The only major issue with older animals is difficulGolden Lion Tamarin (Leontidius sp.) perching on a branch (photo by K. Bayne).

......
......



Marmosets & Tamarins

ty in chewing solid food because of tooth wear and loss. In these cases, soaking 

food in liquids prior to feeding or provisioning animals with softer diets are two 

easy solutions. 

 

In terms of normal social development, most institutions that rear marmosets 

and tamarins have a policy of keeping young individuals in their family groups 

until they have had exposure to and experience with one or more sets of younger 

siblings. It is assumed that this experience will increase the likelihood of success 

in rearing young when the animals are placed in a position where breeding is 

possible. As mentioned above, however, older siblings are sometimes involved 

in mild to serious fights with same-sex siblings, and may need to be removed 

from the group. Decisions about removing an individual from a group should 

be made in light of the need for normal experience with siblings and the seriousness of the aggression. 

Rejection of infants by parents and the inability of infants to maintain contact 

with caregivers are fairly regular occurrences in captive marmosets and tamarins. 

In some cases, lack of infant success is associated with infant health and vigor 

(e.g., low birth-weight infants are unable to maintain a grip on their parent’s 

fur). In other cases, parents (particularly mothers) may actively reject and fail 

to carry and nurse their infants. A number of zoos and research facilities have 

reported some success in hand-rearing infants. Specific details of hand-rearing 

protocols can be found in the Callitrichid Husbandry Manual.

It is important to note that hand-rearing is associated with a variety of behavioral problems, particularly as the hand-reared individuals reach reproductive age. 

Therefore, decisions about hand-rearing rejected infants should involve a careful 

consideration of the animal’s purpose in the facility as an adult. An individual 

that is highly aggressive toward people may not be a good animal for a zoological exhibit, for example. 

 

Individual Housing

Like other primates, marmosets and tamarins are highly social, and individual 

or solitary housing is strongly discouraged. In the event that animals need to be 

housed individually, efforts should be taken to maximize regular social contact 

with caretakers. Marmosets and tamarins have been housed successfully with 

birds or rodents. Specific examples of successful mixed-species housing can 

be found in the Callitrichid Husbandry Manual. However, in no case should 
Marmosets & Tamarins

......

10

a marmoset or 

tamarin be housed 

with a New 

World primate 

from the Family 

Cebidae, including 

squirrel monkeys, 

capuchins, spider 

monkeys. Cebids 

can carry viruses, 

such as Herpesvirus 

saimiri, that do 

not affect their 

own health but 

could be lethal for 

marmosets and 

tamarins. 

 

In the event that 

animals do require 

individual housing, efforts should be taken to compensate for the isolation by 

providing additional enrichment. Increased and regular positive social contact 

with caretakers should be encouraged, but these people should be familiar and 

non-threatening to the animals. Increasing the complexity of the physical environment with live plants or other cage furnishings is also a worthwhile endeavor. 

Marmosets and tamarins rely extensively on vocalizations for communicating 

both within and between groups, and isolated animals can be stimulated to call 

by hearing vocalizations from their own or related species.

Downloadable versions of vocalizations can be found in a variety of locations 

(e.g., http://pin.primate.wisc.edu/av/vocals/). 

Safety Issues

As with all primates, marmosets and tamarins do not like handling, and alternatives to handling should be sought. The animals are easily trained to do a variety 

Infant Wied’s black tufted-ear marmoset, Callithrix kuhlii 

(photo by J. E. Fite).

......
......

11

Marmosets & Tamarins

of tasks (e.g., present for physical examination, sit on a scale for weighing, 

voluntarily enter a transport cage). Training works best if the animals are worked 

regularly and if training occurs before the day’s feeding. However, even well-fed 

animals can be trained with highly preferred food items. Detailed examples and 

descriptions of procedures can be found in the Callitrichid Husbandry Manual. 

Marmosets and tamarins should be handled as little as possible, since they tend 

to be highly reactive to unusual stressors. For routine procedures that are short 

(less than five minutes), such as physical examination or biological sample 

collection, hand-held restraint can work well. Animals can be captured with 

fine-mesh nets (“butterfly net mesh”) and removed by hand. However, the netting procedure can be a major stressor for other group members. Animals can 

be readily trained to enter a detachable nest box, and removing the animal in 

a separate procedure room can minimize this distress. Handlers should wear 

protective leather gloves. A grip from behind the animal’s back, with thumb 

and middle finger underneath the forearms, provides the most secure holding 

position. Most animals will take treats during this restraint, which can serve as a 

reward and enrichment during the handling. If handlers are also caretakers, different clothing should be worn during manual restraint procedures to minimize 

distress for the animals during other routine caretaking activities. 

 

For procedures of longer duration, animals should be given some form of 

chemical immobilization. Ketamine hydrochloride (intramuscular injection) 

provides good immobilization for medium-term procedures (5 - 15 minutes) 

and suggested dosages are provided in the Callitrichid Husbandry Manual. For 

long-term procedures (more than 15 minutes) inhalable anesthetics are recommended, particularly isoflurane. A cat-sized face mask can be used to deliver the 

anesthetic. Some facilities have had success in inducing isoflurane anesthesia by 

placing the animal into an empty 2-liter plastic soda bottle with a removable 

bottom, and directing the anesthetic gas into the bottle. This procedure minimizes the struggle and stress of placing the mask over an awake and alert animal. 

For these longer procedures, care should be taken to monitor and maintain core 

body temperature (warming blanket or warm water bottle) since body temperature can drop quickly in an anesthetized animal. 
Marmosets & Tamarins

......

12

References 

Abbott DH, McNeilly AS, Lunn SF, Hulme MJ, Burden FJ. 1981. Inhibition of ovarian function 

in subordinate female marmoset monkeys (Callithrix jacchus jacchus). Journal of Reproduction and 

Fertility 63:335-345.

Baker JV, Abbott DH, Saltzman W. 1999. Social determinants of reproductive failure in male 

common marmosets housed with their natal family. Animal Behaviour 58:501-513.

Baker AJ, Savage A. 1999. Social management of callitrichids and Callimico. In Callitrichid 

Husbandry Manual. Brookfield, IL: AZA Neotropical TAG.

Bales K, Dietz J, Baker A, Miller K, Tardiff SD. 2000. Effects of allocare-givers on fitness of 

infants and parents in callitrichid primates. Folia Primatol (Basel) 71(1-2):27-38.

Byron JK, Bodri MS. 2001. Environmental enrichment for laboratory marmosets. Lab Animal 

30(8):42-48.

de Rosa C, Vitale A, Puopolo M. 2003. The puzzle-feeder as feeding enrichment for common 

marmosets (Callithrix jacchus): a pilot study. Lab Animal, 37(2):100-107. 

Emlen ST. 1991. Evolution of cooperative breeding in birds and mammals. In JR Krebs and NB 

Davies (Eds.), Behavioural Ecology: An Evolutionary Approach (pp. 301-335). London: Blackwell 

Scientific Publications.

Epple G. 1975. Parental behavior in Saguinus fuscicollis ssp. (Callitrichidae). Folia Primatologica 

24: 221-238.

Epple G. 1986. Communication by chemical signals. In G. Mitchel and J. Erwin (Eds.), 

Comparative Primate Biology, Volume 2, Part A; Behavior, Conservation, and Ecology (pp. 531-580). 

New York: Alan R Liss.

Farmerie M, Neiffer D, Vacco K. 1999. Enrichment and operant conditioning of callitrichids. 

In Callitrichid Husbandry Manual. Brookfield, IL: AZA Neotropical TAG. pp. 64-89.

French JA. 1997. Regulation of singular breeding in callitrichid primates. In NG Solomon and 

JA French (Eds.), Cooperative breeding in mammals (pp. 34-75). New York: Cambridge University 

Press.

French JA, Inglett BJ. 1991. Responses to novel social stimuli in tamarins: A comparative 

perspective. In HO Box (Ed.), Primate responses to environmental change (pp. 275-294). London: 

Chapman and Hall.

French JA, Pissinatti A, Coimbra-Filho AF. 1996. Reproduction in captive lion tamarins 

(Leontopithecus): Seasonality, infant survival, and sex ratios. American Journal of Primatology 39:

17-33.

Heymann EW, Soini P. 1999. Offspring number in pygmy marmosets, Cebuella pygmaea, in 

relation to group size and the number of adult males. Behavioral Ecology and Sociobiology 46:

400-404.

Inglett BJ, JA French, LG Simmons, KW Vires. 1989. Dynamics of intrafamily aggression and 

social reintegration in lion tamarins. Zoo Biology 8:67-78.

Kinzey WG. 1997. Synopsis of New World Primates (16 Genera). In WG Kinzey (Ed.), New 

World Primates: Ecology, Evolution, and Behavior (pp. 222-296). New York: Aldine de Gruyter.

Kleiman DG. 1977. Monogamy in mammals. Quarterly Review of Biology 52: 39-69.

McGrew WC, Brennan JA, Russell J. 1986. An artificial “gum-tree” for marmosets (Callithrix j. 

jacchus). Zoo Biology 5: 45-50.

National Research Council. 1998. The Psychological Well-Being of Nonhuman Primates. 

Washington, DC: National Academy Press. 

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Marmosets & Tamarins

Poole TB. 1990. Environmental enrichment for marmosets. Animal Technology 41(2): 81-86.

Rukstalis M, French JA. 2003. Exposure to conspecific vocalizations modulates stress responses in 

marmosets (Callithrix kuhlii). American Journal of Primatology 60 (Supplement1): 129-130. 

Santos CV, Martins MM. 2000. Parental care in the buffy-tufted-ear marmoset (Callithrix aurita) 

in wild and captive groups. Braz J Biol. 60(4):667-72.

Snowdon CT, Savage A. 1989. Psychological well-being of captive primates: General 

considerations and examples from Callitrichids. In E Segal (Ed.), Housing, Care, and Psychological 

Well-being of Captive and Laboratory Primates (pp.75-88). Park Ridge, N.J.: Noyes Publications.

Snowdon CT, Soini P. 1988. The Lion Tamarins, Genus Leontopithecus. In RA Mittermeier, AB 

Rylands, AF Coimbra-Filho and GAB Fonseca (Eds.), Ecology and behavior of neotropical primates 

(Vol. 2, pp. 223-298). Washington, D.C.: World Wildlife Fund.

Sodaro V. 1999. Social management of callitrichids and Callimico. In Callitrichid Husbandry 

Manual. Brookfield, IL: AZA Neotropical TAG.

Soini P. 1988. The Pygmy Marmoset, Genus Cebuella. In RA Mittermeier, AB Rylands, AF 

Coimbra-Filho and GAB Fonseca (Eds.), Ecology and behavior of neotropical primates (Vol. 2, pp. 

79-129). Washington, D.C.: World Wildlife Fund.

Stevenson MF, Rylands AB. 1988. The Marmosets, Genus Callithrix. In RA Mittermeier, AB 

Rylands, AF Coimbra-Filho and GAB Fonseca (Eds.), Ecology and behavior of neotropical primates 

(Vol. 2, pp. 131-222). Washington, D.C.: World Wildlife Fund.

Tardif S, Carson RL, Gangaware BL. 1990. Infant-care behavior of mothers and fathers in 

a communal-care primate, the cotton-top tamarin (Saguinus oedipus). American Journal of 

Primatology 22: 73-85.

Tardif SD, Clapp NK, Hence MA, Carson RL, Knapka JJ. 1988. Maintenance of cotton-top 

tamarins fed an experimental pelleted diet versus a highly diverse sweetened diet. Laboratory 

Animal Science 5: 588-591.

Wissman MA. 1999. Nutrition and husbandry of callitrichids (marmosets and tamarins). 

Veterinary Clinics of North America: Exotic Animal Practice 2(1): 209-240.

Other Resources

Callitrichid Husbandry Manual, produced by the American Zoological Association. E-mail: 

bzadmin@brookfieldzoo.org 

The Psychological Well-Being of Nonhuman Primates, produced by the Institute for Laboratory 

Animal Research of the National Resource Council, at http://books.nap.edu/books/0309052335/

html/index.html

Common Names of the Callitrichids

Marmosets:

Callithrix acariensis: Rio Acarí marmoset

C. argentata: Black-tailed marmoset, Silvery marmoset

C. aurita: White-eared marmoset, Buffy tufted-ear marmoset

C. chrysoleuca: Golden marmoset, Silky marmoset, Golden-white tassel-ear marmoset

C. emiliae: Snethlage’s marmoset

C. flaviceps: Buff-headed marmoset, Buffy headed marmoset, White-eared marmoset, Whiteheaded marmoset
Marmosets & Tamarins

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14

C. geoffroyi: White-fronted marmoset, Geoffroy’s marmoset, Geoffroy’s tufted-ear marmoset

C. humeralifer: Santarem marmoset, Tassel-eared marmoset, Black and white tassel-ear marmoset, 

White-shouldered marmoset, Golden marmoset, Silky marmoset, Yellow-legged marmoset

C. intermedia: Aripuanã marmoset

C. jacchus: Common marmoset, White ear-tufted marmoset, Tufted-Ear marmoset

C. kuhlii: Weid’s black tufted-ear marmoset

C. lucippe: Golden-white bare-ear marmoset

C. manicorensis: Manicore marmoset

C. marcai or Callithrix argentata marcai: Marca’s marmoset

C. mauesi: Rio Maues marmoset, Maues marmoset

C. melanura: Black-tailed marmoset

C. nigriceps: Black-headed marmoset

C. penicillata: Black-eared marmoset, Black ear-tufted marmoset, Black-pencilled marmoset, 

Black-plumed marmoset

C. saterei: Satere marmoset

Cebuella pygmaea: Pygmy marmoset

Goeldi’s Monkey

Callimico goeldii: Goeldi’s marmoset, Goeldi’s tamarin, Calimico

Tamarins

Saguinus bicolor: Pied tamarin, Bare-faced tamarin, Pied bare-face tamarin, Brazilian bare-faced 

tamarin

S. fuscicollis ssp: Ávila Pires’ Saddle-back tamarin, Crandall’s Saddle-back tamarin, Cruz Lima’s 

saddle-back tamarin, Spix’s saddle-back tamarin, Lesson’s saddle-back tamarin, Illiger’s saddleback tamarin, Red-mantle saddle-back tamarin, Andean saddle-back tamarin, White saddle-back 

tamarin, Geoffroy’s saddle-back tamarin, Saddle-back tamarin, Weddell’s saddle-back tamarin

S. geoffroyi: Geoffroy’s tamarin, Rufous-naped tamarin

S. graellsi: Rio Napo tamarin, Graell’s black-mantle tamarin

S. imperator ssp: Black-chinned emperor tamarin, Bearded emperor tamarin

S. inustus: Mottle-faced tamarin

S. labiatus ssp: Red-bellied tamarin, Red-chested tamarin, Red-chested mustached tamarin, 

Thomas’ mustached tamarin

S. leucopus: White-footed tamarin, Silvery-brown bare-faced tamarin, Silvery-brown bare-face 

tamarin

S. martinsi: Martin’s tamarin, Martin’s bare-face tamarin, Ochraceous bare-face tamarin

S. midas: Midas tamarin, Red-handed tamarin, Golden-handed tamarin, Rufous-handed tamarin, 

Lacepede’s tamarin

S. mystax ssp: Moustached tamarin, Red-capped tamarin, White-rump mustached tamarin

S. niger: Black-handed tamarin

S. nigricollis: Spix’s black mantle tamarin, Black-mantle tamarin, Black-mantled tamarin, Blackand-red tamarin

S. oedipus: Cotton-top tamarin, Pinche marmoset, Cotton-head tamarin, Cotton-tops, Liszt 

monkey

S. tamarin: Negro tamarin 

S. tripartitus: Golden-mantled tamarin, Golden-mantle saddle-back tamarin

S. weddelli: Weddell’s tamarin
enrichment for nonhuman primates

A. Michele Schuler, D.V.M., Ph.D

Primate Research Laboratory, University of South Alabama

Christian R. Abee, D.V.M.

University of Texas MD Anderson Cancer Center

Squirrel 

Monkeys (Saimiri)
......



Squirrel Monkeys

......

Squirrel Monkeys

Background 

 

Habitat 

Squirrel monkeys are inquisitive, predominately tree-dwelling primates that 

spend the majority of their time in the middle level canopy of the forest. Their 

distribution includes an isolated population in the rainforest of Costa Rica 

and virtually the entire Amazon Basin of South America. In the wild, squirrel 

monkeys inhabit most types of tropical forest including both wet and dry forest, 

continuous and secondary forest, mangrove swamps, riparian habitat, and forest 

fragments. They are very flexible in their ability to adapt to different environments and, in some geographic areas, appear to prefer habitats that have been 

disturbed by humans.

 

Physical Features 

The male squirrel monkey weighs 

approximately 550-1135 grams, while 

the female weighs from 365-750 

grams. The male exhibits an increase 

in body weight-- particularly in the 

arms, shoulders and trunk of the 

body-- during the breeding season, 

referred to as the “fatted male” syndrome. This increase in body weight is accompanied by an increase in spermatogenesis. The tail of the squirrel monkey is long, but not prehensile. The legs are 

longer than the arms. The hair coat is short and dense, with coloring ranging 

from grey-green on the back of the animal to white, yellow or orange on the 

underside. There is typically a tuft of black hair on the tip of the tail.

 

Squirrel monkey in a complex, naturalistic 

environment (photo courtesy of C. Abee).
Squirrel Monkeys

......



Wooden branch used as a perch (photo courtesy of C. Abee).

Behavior 

Squirrel monkeys are omnivores that eat insects, eggs, and small vertebrate 

animals, in addition to various fruits, flowers, and tender leaves. In captivity, 

squirrel monkeys can live to be 25 years of age. 

 

Squirrel monkeys primarily use all four limbs to move, employing their tails for 

balance as they navigate along tree branches. They occasionally stand on two 

limbs to walk short distances and to grasp food items with both hands. As a 

tree-dwelling species, they make use of vertical as well as horizontal space. Although they often descend to the ground or floor of their enclosure, they prefer 

to leap from perch to perch. Lacking the bone structure for sitting, they perch 

rather than sit, frequently using their tails for balance. Perches should be round 

in shape rather than flat shelves, as the development of pressure sores on the tail 

has been associated with flat shelves.

Social interactions frequently observed within squirrel monkey groups include 

grooming behaviors, “calling” (i.e., vocalizations), play, displays of aggression, 

and huddling. Vocalizations help to maintain the social organization of squirrel 

monkey troops. Squirrel monkeys use calls to enhance group coordination and 

cohesion. It has been suggested that squirrel monkeys can differentiate individuals using vocal cues and communicate within the troop even when they cannot 

see each other.

 
......



Squirrel Monkeys

Communication between animals within a given social group includes olfactory, visual, and vocal signals. Olfaction is most important during the breeding 

and birthing seasons. Males use scent to determine the receptivity to mating 

of females. In addition, female monkeys use scent to identify individual infant 

animals. When cleaning the animals’ enclosures, it is beneficial to the monkeys 

to avoid strong, artificially scented products.

 

Visual cues are of primary importance in visual displays. Squirrel monkeys make 

these displays in an attempt to assert dominance or reduce tension between individuals. Visual cues involving facial expressions can be associated with fear or 

aggression. A penile display, associated with spreading of the thighs, is considered to be a dominance gesture. Enclosures should provide a place for a submissive monkey to break the stare of a more aggressive monkey. Such places are 

called “hide-boxes” and can be made from a piece of a large-diameter polyvinyl 

chloride (PVC) pipe or another impervious material.

Vocal signals are of the utmost importance for squirrel monkeys. Infants possess 

a wide repertoire of sounds, including grumbles, cackling, purrs, chucks and 

peeps. These sounds communicate the well-being of the infant to the mother. 

In adults, calls are used to signal alarm, to display general disturbance or excitement, and to establish contact with the group when visually separated. 

 

Mating and Reproduction

Social behavior in squirrel monkeys depends on the phase of the reproductive 

cycle. These monkeys become sexually mature at approximately three to four 

years of age. While reproductive efficiency declines beginning at about 12 years 

of age, they can continue to reproduce for several more years. During breeding season (December through February in the northern hemisphere), male 

monkeys tend to be more inquisitive, aggressive, and active. At the same time, 

receptive female monkeys are less likely to respond with an aggressive display 

or facial expression when approached. After the breeding season, males become 

less involved in the social group, often remaining on the perimeter of the group. 

Females tend to perch with other females of similar age. These female-female 

interactions may include infant-care sharing and grooming behaviors.

The gestation period lasts approximately 168-182 days. During the birthing season (usually May to August in the northern hemisphere), older females without 
Squirrel Monkeys

......



infants will act as “baby-sitters” or “aunts,” often carrying infants for the mother. 

This maternal behavior by females other than the mother may include nursing another female’s infant. This is a common characteristic of squirrel monkey 

breeding groups. Occasionally, juvenile animals can pose a threat to nursing 

infants as they can be aggressive to the new babies. Care should be taken when 

housing expectant/new mothers with juvenile animals.

Social World

Consideration of the needs of squirrel monkeys in captivity should extend 

beyond their basic physiologic requirements. These animals possess a host of 

behaviors that define their species. Putting forth the effort to enhance psychological and physical well-being of squirrel monkeys is essential to meeting the 

needs of this species. Through a well-conceived plan of environmental enrichment, good husbandry practices and a sound program of veterinary medical 

care, anxiety and boredom can be alleviated and natural behavior typical of this 

species can be promoted.

In the wild, squirrel monkeys live 

in large social groups (“troops”) 

containing 20 to 200 animals. In 

captivity, social group size and age 

and sex ratios differ depending 

on the limitations of the housing 

available and purpose for maintaining the animals. 

Efforts should be made to house 

the highly social squirrel monkeys 

in pairs or small groups whenever 

possible. Social groups should be 

maintained with animals born 

into the social group remaining in 

the group as long as is possible. Generally, it is recommended that social groups 

maintained in captivity include only one or two adult males per group, because 

......

Carrying of an infant squirrel monkey

(photo courtesy of C. Abee).
......



Squirrel Monkeys

fighting may develop among males if more than two are housed together within 

the social group. Most of the time, females of varying ages can be housed in 

social groups of two or more with only occasional difficulties with incompatibilities of group members. In fact, housing multiple females per group provides 

breeding animals the social structure necessary to reproduce efficiently. To 

maximize breeding efficiency, as many as 20 females can be housed with a single 

male. An optimal ratio, however, is one male per eight to ten females.

 

Groups that have access to a semi-natural environment with more living space 

are able to accommodate more adult males within the same groupings due to 

the increased complexity and size of the environment, the possibility of emigration to an adjacent group within the enclosure, and the increased provision of 

hiding areas. 

A social group of squirrel monkeys (photo courtesy of C. Abee).
Squirrel Monkeys

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A hiding area for squirrel monkeys

(photo courtesy of C. Abee).

Physical World

 

Housing

Both indoor and outdoor group 

pens can be designed for squirrel 

monkeys. Physical comfort of the 

animals is important in reducing 

stress and promoting the well-being of colony members. Animals 

in outdoor pens have the opportunity to control aspects of their 

environment by moving through 

their pen (e.g., sun or shade). The 

animals are generally free to seek 

the place they wish to spend their 

time. Animals in these pens can 

also self-regulate the amount of exposure to other animals by moving 

within their pen. Perches should 

be positioned at several levels 

within the living area for climbing and jumping. These perches 

can be constructed of PVC pipe, 

which is impervious to water, 

easily cleaned and not highly 

thermoconductive. Wood perches 

can also be used as long as they are 

replaced once they become excessively soiled or become otherwise deteriorated. As noted previously, flat shelves 

should be avoided due to the potential development of pressure sores on the tail 

of the animal. Large PVC pipe sections can be provided for animals to “hide” 

in, allowing them to break eye contact with other members of their social group 

during aggressive encounters. Finally, certain positions within the pen allow the 

monkeys to view, and be viewed by, other social groups, while other positions 

will greatly restrict the number of other animals the individual can see or be seen 

by.

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Squirrel Monkeys

Animals housed in indoor cages, 

on the other hand, have a limited 

ability to regulate their exposure to 

animals housed in other cages by 

positioning themselves in such a 

way as to limit their ability to view 

other animals. Cage configuration will determine the number of 

monkeys that can be housed. Rack 

caging can be used to house small 

groups, pairs, or single animals. 

These cages should also have perches at varying heights to enable the animals 

to maximize their three-dimensional use of space. The Guide for Care and Use 

of Laboratory Animals (NRC 1996) and the Animal Welfare Regulations (1991) 

provide minimum cage space guidelines and requirements. 

In the laboratory setting, it is best to allow the animals to communicate through 

olfactory, visual, and vocal signals. Even in singly-housed animals, this communication can be preserved by arranging the cages to enable the animals to smell, 

see, and hear each other. Outside noise should be kept to a minimum so that 

the group-housed monkeys can hear each other’s vocalizations. By group-housing animals whenever possible, communication becomes an important form of 

social enrichment. 

Each cage should be provided with swings, moving perches, or objects hanging 

within the cage. These can be made of either a plastic chain, looped PVC tube, 

or other similar materials. Smaller, rack-mounted cages will need to have at least 

one such device, while larger group cages should have two or more, depending on the number of monkeys in the cage. Loose hanging devices should not 

be included in individual cages where the room taken up by the swing would 

limit movement of the animal or where the swing is not appropriate for clinical 

reasons.

Being neotropical primates, squirrel monkeys thrive in warm temperatures. In 

captivity, temperatures should be maintained between 78°-85°F. Relative humidity should be maintained above 50% if possible. If relative humidity falls below 30%, squirrel monkeys can develop crusts around the nostrils and frequent 

sneezing. Special care must be taken in cooler climates to prevent hypothermia.

A plastic chain swing (photo courtesy of C. Abee).
Squirrel Monkeys

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Enrichment

In all caging conditions, a 

number of different food items 

and perch arrangements can be 

used to vary the environment of 

the animals and consequently 

increase activity levels and 

sensory stimulation. Perch 

arrangements with hanging 

objects, such as infant toys and 

practice golf balls, should be 

rotated and replaced routinely. 

Objects must be large enough to prevent swallowing and sturdy enough not 

to be broken into small pieces. Food treats should be nutritious. Fruit and 

vegetables must be selected for quality and should be washed prior to feeding.

Occasionally, squirrel monkeys can experience anxiety when exposed to novel 

stimuli. Care must be taken, particularly with animals in smaller enclosures, 

to ensure that changes are not distressing to the animals. Animals should be 

observed after introduction of new objects to determine whether they show 

signs of fear or avoidance of the object. If this occurs, the object should be 

removed. In larger 

enclosures, this is 

less of an issue, as 

the monkeys can 

move away from 

new objects and 

acclimate slowly.

 

 

An enrichment item that can be manipulated by the 

animals (photo courtesy of C. Abee).

Food items can be suspended, to make them more challenging to consume 

(photo courtesy of C. Abee).
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Squirrel Monkeys

Feeding

The animal’s primary diet should be an appropriate, commercially available diet. 

In addition, each monkey’s diet should be supplemented with fruit and vegetables according to what is seasonally available (although squirrel monkeys can 

have problems with their teeth associated with a high sugar diet; therefore, vegetables are preferred over sweet fruits). Items may include melon, oranges, apples 

(note that there is some evidence that apples may be associated with bloat, a 

frequently fatal disease where the stomach fills with gas), Kiwi fruit, strawberries, pears, bananas, grapes, celery, bell peppers, tomatoes, carrots, and sweet 

potatoes. Additional items, such as various flavors of Gatorade®, multi-vitamins, 

and food-pellet rewards for correct responses may be added for experimental or 

clinical reasons. To encourage foraging, food items can be placed in the cage or 

pen floor after daily cleaning. This encourages the animals to move about the 

cage to select their food. Additional food items can be placed in hanging PVC 

tubes that require the monkeys reach into the tube to find food items.

 

Highly desired food items should be handed out by caregivers at least twice 

daily, for example during daily observations of the animals. This positive interaction with caregivers allows the animals to habituate to the caregivers and allows 

the caregivers to interact in a non-threatening, positive way with the animals.

Sanitation

Standards for the sanitation of caging for squirrel monkeys housed indoors are 

well-described in the National Research Council’s Guide for the Care and Use 

of Laboratory Animals (1996). However, many squirrel monkeys are housed in 

semi-naturalistic environments, where they may be exposed to numerous parasite hosts, such as mollusks, frogs, and small snakes as well as soil and water that 

may have been contaminated by rodents carrying transmissible diseases such as 

leptospirosis. Sanitation programs should include diligent exclusion of slugs, 

snails, frogs, rodents, and as many insects as possible—particularly in tropical environments—to minimize exposure of the animals to these parasite and 

disease hosts.

 

 

 

 

 
Squirrel Monkeys

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10

Special Cases

Age-related Considerations 

If possible, infants and young juveniles should be housed with their mothers 

and remain within their natal social group. Attempts should be made to find 

appropriate foster-mothers for newborn infants that are rejected or orphaned. 

Failing this, or if the newborn is clinically compromised and unable to cling 

normally to a female, it can be housed in a separate nursery. Nursery infants can 

be housed in small, wire-mesh cages. They should be given a cloth surrogate 

mother approximately the same diameter as an adult female monkey to provide 

contact comfort. Infants in the nursery need frequent, positive contact from the 

caregivers as part of the feeding schedule. This contact varies from every hour 

to every four hours depending upon the age of the animal. As the infants grow 

older and strong enough to interact with other infants, they can be moved to a 

larger enclosure with other similarly aged infants. The cage should be equipped 

with multiple levels of perching and swings for the animals to move and jump 

from one to the next. When nursery-reared infants become old enough (6 - 12 

months of age) to eat on their own and move about within a social group with 

adults, they can be introduced into a social group within the general colony.

 

Individual Housing

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A surrogate “mother” for a nursery-reared infant squirrel monkey (photo courtesy of C. Abee).
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11

Squirrel Monkeys

Abnormal social behavior (e.g., over- or under-aggressiveness) that is the result 

of incompatible social partners can result in an individual being removed from 

its current social group to another social group or individual housing for a 

period of time. If the animal is a danger to other animals, a qualified veterinarian 

should determine whether the animal should be placed in an individual cage. In 

addition, individual housing should be considered when animals cannot defend 

themselves from the normal dominance-related aggression that occurs in this 

species and for acute or chronically sick and debilitated animals. 

All individually housed animals should be provided with multiple perches, varied foods, and frequent contact with familiar caregivers. The U.S. Department 

of Agriculture requires that exemptions (e.g., for health or behavioral reasons) 

from social housing must be recorded by the attending veterinarian. In research 

programs, the Institutional Animal Care and Use Committee may exempt 

individual animals from participating in the social enrichment portion of the 

enrichment program when such housing is justified for experimental reasons. 

Every attempt should be made to ensure that there is direct visual, auditory, 

and/or olfactory contact with other squirrel monkeys. Animals that are unable 

to see and hear other squirrel monkeys may be given access to auditory stimuli 

from another room containing squirrel monkeys via a microphone-speaker 

arrangement or a pre-recorded audio tape. Extra contact with familiar caregivers should be provided. In addition to frequent visits, caregivers should provide 

much-desired food treats. Live prey, such as mealworms and crickets, can be 

used to increase the stimuli that food treats can provide. Toys, perches, swings, 

and other hanging devices should be rotated more frequently. Mirrors can also 

be used to provide sensory stimulation.

 

Attempts to socially house squirrel monkeys should be documented for both 

internal tracking purposes and for government regulatory agencies. Some animals that do poorly in large social groups can be housed together with a small 

number of other animals that similarly can not live in large social groups. This 

arrangement will allow social contact with other squirrel monkeys while reducing the level of competition for resources. 
Squirrel Monkeys

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12

Problem Behaviors

Abnormal non-social behavior, including stereotypical movements and self-injurious behaviors, may necessitate a change in housing structures, enrichment 

objects or reinforcement techniques. For example, “pacing” may be eliminated 

by increasing the animal’s available travel paths by installing additional perches. 

Self injurious behavior, such as self hair-pulling and self-biting, often are the 

result of unusual stress. If such behavior is seen in an animal, an evaluation 

should be made of the animal’s current social status and housing environment. 

These animals should also receive a physical examination by a veterinarian to 

determine their health status.

Safety Issues

By far the most effective method for restraining squirrel monkeys is the use of 

leather gloves designed for handling small primates. These gloves provide protection to the human worker while preventing injury to the monkey. As with any 

restraint technique, technicians must be adequately trained to assure that the 

animal is restrained without injuring it. With practice and continued vigilance, 

the use of heavy leather gloves is a safe method of restraint for both the handler 

and the monkey. The use of nets to catch/restrain squirrel monkeys is not recommended. These animals are prone to fractures of the appendages when nets 

are used.

Squirrel monkeys can be trained to jump from cage to cage during rack changes. 

For cleaning of larger enclosures, it is not necessary to remove the animals prior 

to cleaning as long as noxious chemicals are not used and if the animals can 

perch above or away from the area being cleaned.

 

Chemical restraint may be considered by the veterinarian to restrain squirrel 

monkeys for transport and medical care in an attempt to reduce the stress and 

hazards associated with working with these monkeys. Ketamine hydrochloride, 

either with or without xylazine, can be used by the veterinarian for brief sedation. 

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13

Squirrel Monkeys

Squirrel monkeys are wild animals and 

must be treated as such. They can injure 

caregivers through bites and scratches. 

But because they do not carry Cercopithecine herpesvirus 1 (Herpesvirus simiae

or B-virus), a bite or a scratch from a 

squirrel monkey can be treated much 

like the bite from a domestic dog or cat. 

Regardless, care must be taken when 

handling these animals to prevent injury 

to both the caregiver and the animal. 

While it is unlikely that infectious 

diseases would transfer from squirrel 

monkeys to humans, and vice versa, 

common-sense precautions should be 

taken when working with any animal: 

immunocompromised workers should not handle animals with any known illness; masks should be worn when aerosols are present; any worker with an active 

upper respiratory infection should not handle animals; and consultation with a 

health professional may be necessary. Finally, although current human vaccination protocols include vaccination against measles, should an infection occur in 

any individual who resides with the animal caregiver, that caregiver should avoid 

any contact with squirrel monkeys until the infection has resolved. Measles 

spreads rapidly and is fatal in squirrel monkeys.

 

 

References

Abee CR. 1985. Medical care and management of the squirrel monkey. In LA 

Rosenblum and CL Coe, eds., Handbook of squirrel monkey research, 447-488. 

Plenum Press: New York.

Abee CR. 2000. Squirrel monkey (Saimiri spp.) research and resources. ILAR 

Journal 41:2-9.

Brady AG. 2000. Research techniques for the squirrel monkey (Saimiri sp.). 

ILAR Journal 41:10-18.

Use of a leather glove for manual restraint of a 

squirrel monkey (photo courtesy of C. Abee).

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Squirrel Monkeys

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14

DuMond FV. 1968. The squirrel monkey in a seminatural environment. In 

L.A. Rosenblum and R.W. Cooper, eds. The Squirrel Monkey, 31-68. New York: 

Academic Press.

Dunn FL. 1968. The parasites of Saimiri. In L.A. Rosenblum and R.W. Cooper, 

eds. The Squirrel Monkey, 31-68. New York: Academic Press.

Napier JR and Napier PH. 1967. A Handbook of Living Primates. New York: 

Academic Press.

National Research Council. 1998. The Psychological Well-Being of Nonhuman 

Primates. Washington, DC: National Academy Press.

National Research Council. 1996. Guide for the Care and Use of Laboratory 

Animals. Washington, D.C: National Academy Press. 

Reinhart V (ed). 1997. Comfortable Quarters for Laboratory Animals, 8th edition. 

Washington, DC: Animal Welfare Institute.

Rosenblum LA, Coe CL (eds). 1985. Handbook of Squirrel Monkey Research. 

New York: Plenum Press.

United States Department of Agriculture, Animal and Plant Health Inspection 

Service. 1999. Final Report on Environmental Enhancement to Promote the 

Psychological Well-Being of Nonhuman Primates.

Williams LE, Abee CR, Barnes SR, Ricker RB. 1988. “Cage design and 

configuration for an arboreal species of primate.” Laboratory Animal Science. 

38: 289-291.

 

 

Common Names of Squirrel Monkeys

Saimiri boliviensis: Bolivian squirrel monkey, Peruvian squirrel monkey

S. oerstedii: Grey-crowned Central American squirrel monkey, Black-crowned 

Central American squirrel monkey

S. sciureus: Humboldt’s squirrel monkey, Ecuadorian squirrel monkey, Common 

squirrel monkey, South American squirrel monkey

S. ustus: Bare-eared squirrel monkey, Golden-backed squirrel monkey

S. vanzolinii: Blackish squirrel monkey, Black squirrel monkey, Black-crowned 

squirrel monkey, Black-headed squirrel monkey

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This series of booklets on enrichment for nonhuman 

primates was made possible through the cooperation of: 

~ Department of Health and Human Services

~ NIH, Office of Laboratory Animal Welfare (OLAW)

~ US Department of Agriculture, Animal Care

~ Association of Primate Veterinarians

~ American Society of Primatologists

For more information, contact OLAW at NIH

tel: (301) 496-7163, e-mail olaw@od.nih.gov

Department of Health and Human Services, 2005

enrichment for nonhuman primates