DOI: 10.5061/dryad.cc2fqz695
title: The biology of prolonged lactation in wild Macaca sinica: Interbirth intervals, maternal depletion, infant mortality

description: A sample of 442 female toque macaques distributed among 39 independent
 social groups were briefly captured, sedated, and released (within one
 day) during 13 different years in the period 1986-2002 at the natural
 forest site of Polonnaruwa, Sri Lanka, where long-term sociobiological
 research has been conducted (1968 to 2023).  All macaques were
 individually identified and had known life-histories.  Lactation
 was determined by testing females for the presence of absence of milk by
 manually massaging the mammary tissue.  Female reproduction in
 this wild population was depicted from different perspectives. 
 Firstly, lactation and weaning were linked to offspring age, as well as to
 female reproductive status (cycling, gestation, and quiescence). 
 A second data set examines interbirth intervals in relation to lactation
 duration, diet, and somatic growth or parity. Differences in diet quality
 were also related to menarche.  A third data set examined female
 body condition (using skinfold thickness as a measure of % body fat) to
 diet quality and differences in the expenditure of foraging time between
 lactating and non-lactating females. A fourth data set considered the
 relation between infant mortality during peak lactation and the depletion
 of female metabolic energy balance as indexed by early weaning (cessation
 of lactation) and a shift to female reproductive quiescence.  In
 the publication some of these data  were integrated with
 mother-infant behavioral relationships as cited from an independent study
 of the same population. A final data set indicates the names of
 participants who contributed to both the long-term demographic records,
 milk collections and estimates human effort for different phases of this
 research.
description: <strong>Individual animal identification:</strong>
 The methods involve hand-written notes of field observation of
 individually identified macaques in their natural habitat at Polonnaruwa,
 Sri Lanka, according to established protocols as described in earlier
 publications.National Research Council (1981). Techniques for aging and
 sexing primates. In: Techniques for the Study of Primate Population
 Ecology. pp 81-134.  Washington, DC, National Academy Press.  Also:
 Dittus, WPJ (1990). Manual for the Identification of Individual Toque
 Macaque, unpublished training manual, Smithsonian Primate Biology Program.
 All research staff are trained in these methods. 
 <strong>Vital
 statistics:</strong> (dates of birth and death, age,
 survival, death, sex, reproductive conditiion) are based on monthly census
 of all macaque groups by trained field staff. During the birth season
 females were observed more frequenlty in order to poinpoint dates of
 birth.  <strong>Milk
 sampling:</strong> Temporary capture and sedation of macaques was
 used for purposes of milk tests.  Methods were published in: Milligan LA,
 Rapoport S, Cranfield MR, Dittus WPJ, Glander KE, Oftedal OT,... Bazinet
 RP. (2008). Faty acid composition of wild anthropoid primate milks.
 Comparative Biochemistry and Physiology, part B 149: 74-82. doi:
 10.1016/jbpb.2007.08.006.  Mammary tissue was manually massaged, or nipple
 stipped, to check for the presence or absence of milk.  
 <strong>Intergation of data
 sets:</strong> Information from different data logs were entered
 into EXCEL spreadsheets for examination of relationships among different
 variables: infant age, milk presence, lactation, weaning, infant and
 maternal death, interbirth intervals, female reproductive states, female
 body condition, foraging duration, diet quality.  Reproductive states were
 defined in the 3rd wordsheet (tab) of the first data set as well as in the
 publication. Column headings (variables) were defined in the second tab of
 the first data set. 
 <strong>Definitions:</strong> All dataset files and
 variables were defined in the
 README_DITTUS_Lactation_interbirth_intervals_female_reproduction_maternal_depletion.txt
description: Microsoft 365 EXCEL for spreadsheet entries. (Microsoft
 corporation)  SigmaPlot 14.5 for statistical analysis
 and graphic figures. (SYSTAT software Inc.) Microsoft
 365 WORD for document format. (Microsoft Corporation)
description: This readme file was generated on 2023-12-08 by Wolfgang Dittus GENERAL
 INFORMATION Title of Dataset: Dataset re lactation, weaning age,
 interbirth interval, offspring survival, female reproduction &
 behavior for wild Macaca s sinica in Sri Lanka (1971-2002).
 Author/Principal Investigator Information Name: Wolfgang P J Dittus (WD)
 ORCID: 0000-0001-7981-3968 Institution: Smithsonian Institution USA, &
 National Institute of Fundamental Studies, Sri Lanka Address: Washington,
 DC,20008 Email: wdittus@gmail.com; DittusW@SI.edu; Wolfgang.di@nifs.ac.lk
 Author/Associate or Co-investigator Information Name: Anne M. Baker (AB)
 ORCID: n/a Institution: Association for the Conservation of Primate
 Diversity Address: Polonnaruwa, Sri Lanka and Jonesboro, MA 04648 Email:
 annebaker@ix.network.com Date of data collection: Deomography (vital
 statistics), Ecology & Behavior: 1968/10/15 to 2002/10/15.(WD)
 Mother-Infant behavioral relationships: 1977-1983 (AB) Milk sampling:
 1986/09/20 to 2002/10/15 (WD) Geographic location of data collection:
 Polonnaruwa Archaeological Reserve and Nature Sanctuary (the study area)
 Latitude/longiture: 7.991474 / 80.99579 Town: Polonnaruwa, North Central
 Provinve, Sri Lanka Smithsonian Primate Research Station (shown on Google
 map for Sri Lanka) Information about funding sources that supported the
 collection of the data (1968-2002): Data relevant to the lactation study
 were 2 in kind: (1) Milk related investiagtions (1986-2002). No direct
 funding, work was ancillary to genetic research (capture-process-release)
 under several grants listed below.\ (2) Long-term (1968-2002) vital
 statistics for individual animals. Data were integral to varied objectives
 supported by many grants 1968-2002 as listed below. Smithsonian
 Institution: 1968-1972 (PI: John Eisenberg) NSF GB-3545. Smithsonian
 Foreign Currency; 1968-1972 (PI:John Eisenberg) # SFC-7004 National
 Geographic Society: 1975-1986 (Wolfgang Dittus, WD)#1442 US National
 Science Foundation (NSF): 5 grants, 1976-1996 (WD
 #BNS-7619740,-7924057,-8300092,-8609665,-9104649) US National Science
 Foundation (NSF): 1986-1989 joint grant (Don Melnick and WD)
 (#BNS-8608187,-8909775) Wenner-Gren Foundation for Anthropological
 Research: 1980. (WD) #3199 Harry Frank Guggenheim Foundation: 2 grants,
 1986-1992 (WD) Smithsonian Institution Scholalry Studies: 3 grants,
 1986-1998 (WD) Smithsonian Institution, Sisley & Abbott Funds, 2
 grants 1999-2003 (WD) Earthwatch: 7 grants 1997-2007 (WD) Deutsche
 Forschungsgemeinschaft, 1976-1978 (WD) #Di73/1 Deutsche
 Forschungsgeneinschaft, 1998-2000. (Peter Nuerberg and WD) Association for
 the Conservation of Primate Diversity: 2004-2022 (WD) SHARING/ACCESS
 INFORMATION Licenses/restrictions placed on the data: n/a Links to
 publications that have used some of the data: 1. Goto K, Fukuda K, Senda
 A, Saito T, Kimura K, Glander K, Hinde K, Dittus W, Miiligan L, Power M,
 Oftedal O, Urashima T. (2010). Chemical characterization of
 oligosaccharides in the milk of six species of New and Old world monkeys.
 Glycoconjugate Journal, 27, 703-715. doi:10.1007/s10719-010-9315-0 2.
 Milligan L, Rapoport S, Cranfield M, Dittus W, Glander K, Oftedal O. . .
 Bazinet, R. P. (2008). Fatty acid composition of wild anthropoid primate
 milks. Comparaative Biochemistry and Physiology, Part B., 149, 74-82.doi:
 10.1016/j.cbpb.2007.08.006 Links to other publicly accessible locations of
 the data: to be determined Links/relationships to ancillary data sets: to
 be determined Was some data derived from another source? Yes, but only for
 Mother-infant behavioral relationships in Macaca sinica (1977-1983) by AB
 Citation: Baker-Dittus, AM. (1985). Infant and juvenile directed behaviors
 in adult toque macaques Macca sinica. (Ph. D. dissertations), University
 of Maryland, College Park. DATA & FILE OVERVIEW File List: File 1:
 Baseline variables and interrelationships relevant to lactation amomg wild
 toque macaques involving female and offspring vital statistics, lactation,
 diet, female body condition, and reproduction.xlsx Contents: (a) female
 identity, age, and survival;(b) offpsring identity, age, sex, and
 survival; (c) presenece or absence of milk,(d) duration of lactation, (e)
 weaning age, (f) female reproductive status (lactation, gestation or
 pregancy, cycling, quiescent and non-reproductive), (g) interbirth
 interval, (h) birth sequence (i) maternal diet quality, (j) female parity,
 (k) menarche, (l) maternal body condition (skinfold thickness). File 2:
 Maternal foraging duration in relation to lactation.xlsx. Contents: (a)
 Female and offspring identity, (b) offspring age and sex, (c) nursing
 behavior (lactation), (d) total observation times (e) maternal foraging
 duration and (f) daily proportion. File 3: Research Participants and
 Roles.xlsx. Contents: A list of personnel names, roles, and periods of
 participation relevant to lactational studies. An estimate of proportions
 of overall effort devoted to different foci of macaque research 1968-2022.
 Relationship between files, if important: Raw data files (#1 and #2) are
 tied by sharing the same set of macaque individuals (and their basic vital
 statistics) involved in the study. The files differ in the objective of
 the analyses and tabulations derived. Additional related data collected
 that was not included in the current data package: Are there multiple
 versions of the dataset? no If yes, name of file(s) that was updated: n/a
 Why was the file updated? n/a When was the file updated? n/a
 METHODOLOGICAL INFORMATION Description of methods used for
 collection/generation of data: Methods for processing the data: Age and
 sex of individuals, dates of birth and death, were derived from long-term
 (1968-2003) project demographic records specific to the individuals used
 in the lactation study. See: National Research Council (1981). Techniques
 for aging and sexing primates. In: Techniques for the study of primate
 population ecology. Washington, DC: The National Academies Press, pp
 81-134., as well as Dittus, W. P. J.
 (1990). Manual for the identification of individual toque macaques (Macaca
 sinica). Smithsonian Primate Research Station. Polonnaruwa, Sri Lanka.
 Milk was expressed, or not, by massaging the mammary tissue of sedated
 females with sterile gloved fingers. Instrument- or software-specific
 information needed to interpret the data: EXCEL v 365 spread sheets were
 used for data compilation. Microsoft Corporation. Statistical analyses
 (Survival analysis) and graphic displays were made using SigmaPlot version
 14.5. SYSTAT Software Inc. Standards and calibration information, if
 appropriate: n/a Environmental/experimental conditions: There were no
 experimental conditions used. Environmental: All field procedured
 (demographic census, behavioral observations, capture and realese and milk
 sampling) were carried out in the natural forest habitat of the
 Polonnaruwa Nature Sanctuary and Archaeological Reserve, Sri Lanka. The
 natural forest structure, climate, and geography and layout of the study
 site were described earlier in: Dittus, W. P. J. (1977). The ecology of a
 semi-evergreen forest community in Sri Lanka. Biotropica, 9(4), 268-286.
 doi:10.2307/2388145. And Dittus, W. P. J. (1985). The influence of
 cyclones on the dry evergreen forest of Sri Lanka. Biotropica, 17, 1-14.
 doi:10.2307/2388371. See also Dittus, W. P. J. (2020). Shields on electric
 posts prevent primate deaths: a case study at Polonnaruwa, Sri Lanka.
 Folia Primatologica, 91, 643-653. doi:10.1159/000510176 The process of
 capture and release was described in: Hoelzer G, Dittus W, Ashley M, &
 Melnick D (1994). The local distribution of highly divergent mitochondrial
 DNA haplotypes in toque macaques Macaca sinica at Polonnaruwa, Sri Lanka.
 Molecular Ecology, 3, 451-458. doi:1111/j.1365-294X.1994.tb00123.x
 Capture, release and milk sampling were described in: Milligan L, Rapoport
 S, Cranfield M, Dittus W, Glander K, Oftedal O. . . Bazinet, R. P. (2008).
 Fatty acid composition of wild anthropoid primate milks. Comparaative
 Biochemistry and Physiology, Part B., 149, 74-82.doi:
 10.1016/j.cbpb.2007.08.006 Describe any quality-assurance procedures
 performed on the data: Data quality input was assured through (a) the
 training of field staff according to in-house manuals of Macaque
 Individual Identification (e.g., Dittus 1990) and Research Protocols, (b)
 supervision by experienced staff. Clerical staff cross-checked data
 entries and assured that macaques names and their associated data were
 consistent across data sets. All data are tied to identified individuals
 and their basic demographic variables. People involved with sample
 collection, processing, analysis and/or submission: The file: Research
 participants and roles.xlsx indicates the names of research participants
 involving: demographic census, ecology, behavior, and monkey
 capture-process-release relevant to the lactation study on toque macaques
 (Macaca s sinica) at Polonnaruwa, Sri Lanka (1986-2002) 1. DATA-SPECIFIC
 INFORMATION FOR FILE #1: Baseline variables and interrelationships
 involving female and offspring vital statistics, lactation, diet, female
 body condition, and reproduction.xlsx Data specific information for
 File#1. Baseline raw and derived variables and tabulations concerning
 lactation in wild toque mcaques.xlsx. There are 3 worksheets in this file
 Worksheet #1: Data raw, derived & tabulated. Variables relevant to
 lactation in relation to infant age & female reproductive status
 (columns B to AM), interbirth intervals, diet, maternal body condition,
 infant mortality as well as tabulations and analyses (after column AO) for
 one Table 1 and 11 Figures indicating the relation between different sets
 of variables. Empty or blank cells indicated the absence of data. Color
 coded cells or columns imparted no specific information. Colors were used
 by the author as a guide in the construction of the worksheet. Worksheet
 #2: Column labels and tabulations. Description of variables (headings and
 data content) for columns A to AM in Worksheet #1 Worksheet #3: Definition
 reproductive status. Definition of variables under female reproductive
 status "codes" (Column AG) used in Worksheet #1 and all other
 data sets. Terms used to describe female reproductive conditions are also
 defined in the Methods section of the publication. Number of variables: n=
 23 actively used variables in figures (B to AJ), baseline variables, n= 41
 Number of cases/rows: 814 Variable List: Described in Worksheets #2 (n=
 23) and Worksheet #3 (n=20) Missing data codes: none, see Worksheet #2 for
 definitions. Specialized formats or other abbreviations used: See
 Worksheet #2 for information. 2. DATA-SPECIFIC INFORMATION FOR FILE#2.
 Foraging time versus lactation Macaca s sinica (1971) There is one
 worksheet in this file. Number of variables used in the Figure = 3:
 Proportion of day foraging, vs lactation and non-lactation\ Number of
 baseline variables for derivations = 10, namely: Name of Mother, Date
 Sampled, Name of Offspring, Offspring Birth Date, Infant Age at Sample
 Date, Nursing, Total Min Observed, Total Foraging Time, Proportion of Day
 Foraging. 1. DATA-SPECIFIC INFORMATION FOR FILE #3: Research participants
 and roles.xlsx Research participants involving: long-term demographic
 census, ecology, behavior, & monkey capture-process-release relevant
 to the lactation study on toque macaques (Macaca s sinica) at Polonnaruwa,
 Sri Lanka (1971-2002) Descriptive variables: Researcher name, Researcher
 main focus of work (7 variables); Year of research participation;
 Position; Institution. Number of variables/rows: 73 persons over 54 years.
 17 persons involved in procedure not exclusive to but related to milk
 collection (1986-2002). The long-term demograpahic monitoring of
 individually identified toque macaques from 1968-2022 makes up (38%) of
 personnel man-years. Record collation involved (30%) and capture and
 release proceedure for milk sampling (3.6% )personnel in the relatively
 brief period (1986-2002).