Using behavior and genital swellings to monitor social dynamics and track reproductive cycling in zoo‐housed lion‐tailed macaques (Macaca silenus)

Abstract

Though lion-tailed macaques are managed ex situ as an assurance population, little information is available on the relationship between behavior and reproductive physiology to ensure successful management and evaluate welfare. To facilitate social and reproductive management in a group of one male and three female lion-tailed macaques at Disney's Animal Kingdom ® , we observed behaviors associated with dominance and reproduction, rated genital swellings, recorded menses, tracked ovarian cycles as determined by measurement of fecal immunoreactive progesterone (P4) and estradiol (E2), and monitored fecal cortisol (CORT). We analyzed the dominance hierarchy of females, compared hormone patterns of ovarian cycles with genital swellings and copulations relative to menses, and tested for correlations between hormones and behavior. The strength of the dominance hierarchy indicated moderate linearity, but relaxed after the dominant female received anxiolytic medications to reduce intraspecific aggression. Fecal P4 and E2 patterns revealed ovarian cycle lengths averaging 29.7 ± 0.8 days. The timing of singleday E2 peaks varied between and within females' cycles. However, on average, E2 peaks occurred 6-10 days after the first day of menses, with maximum genital swellings and copulations occurring slightly thereafter in uncontracepted females. Female-to-female aggression and sexual behaviors with the male were related to ovarian cycle phase, but correlations between behaviors and hormones varied between females. Initiated aggression was positively correlated with E2 in the dominant and mid-ranked females, while aggression received was positively correlated with P4 or negatively correlated with E2 in the mid-ranked and subordinate females. In one uncontracepted female, sexual behaviors with the male were negatively correlated to P4. CORT was positively correlated to aggression in the dominant and mid-ranked females and negatively correlated to grooming in the subordinate female. Results indicate observations

Zoo studies in primate physiology, health, and welfare

“…and discuss a variety of factors that may affect reproductive physiology in these species. Using measures of progesterone, estradiol, and cortisol alongside behavior, genital swellings, and menses, Alba et al (2022) tracked reproductive cycling and monitored social dynamics in a group of lion‐tailed macaques ( Macaca silenus ). As reproduction is carefully managed in zoos due to space constraints and to maximize genetic diversity, LeFauve and Margulis (2022) investigated the effect of chemical contraceptives on progesterone and the timing of reproductive behaviors in western lowland gorillas ( Gorilla gorilla ).…”