Skip to main content
Dryad

The biology of prolonged lactation in wild Macaca sinica: Interbirth intervals, maternal depletion, infant mortality

Data files

Dec 18, 2023 version files 272.37 KB

Abstract

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.