The 88th Annual Meeting of the American Association of Physical Anthropologists (2019)


Timing of reproductive onset among female vervet monkeys (Chlorocebus pygerythrus) in wild and human-impacted populations

STACY-ANNE R. PARKE1, ALICIA M. RICH1, MARYJKA B. BLASZCZYK2 and CHRISTOPHER A. SCHMITT1.

1Anthropology, Boston University, 2Anthropology, University of Texas

March 29, 2019 , CC Ballroom BC Add to calendar

The timing of female maturation can be influenced by variation in energetic status, socio-demographic factors, and ecological context. Plasticity in age at first reproduction is, in particular, intimately tied to nutritional context. Here, we explore differences in age at first reproduction among wild female vervet monkeys (Chlorocebus pygerythrus) in South Africa living in “wild-feeding” (Soetdoring Nature Reserve) and “food-enhanced” (!Gariep Dam) social groups. We used ordinal logistic regression models to explore the relationship between body fat (measured by skin fold thickness), parity (assessed through nipple length), and dental age in these populations, and used chi-squared tests to assess proportional differences of nulliparous to parous females between populations. Our results suggest that the maturational milestone of age at first birth occurs in accordance with predicted energetic differences, as it appears delayed among “wild-feeding” females in Soetdoring - which have significantly lower subcutaneous body fat - compared to those in !Gariep Dam. This outcome, however, has only weak statistical support, presumably due to the small sample size of females at pubertal age in !Gariep. We predict that further sampling will strengthen our model and allow for more detailed investigations of the interaction between sexual maturation and human impacts.