1Department of Anthropology, McGill University, 2Makerere Biological Field Station, Makerere University, 3Department of Evolutionary Anthropology, Duke University, 4Department of Anthropology, Hunter College of the City University of New York, 5School of the Environment, McGill University
March 26, 2015 , Archview Ballroom
The availability of food could significantly impact female reproduction, and seasonal variation in this resource can influence the timing of reproductive events. Here we examine the relationship between food availability and the timing of births in vervet monkeys (Chlorocebus pygerythrus) living in a forest-agriculture matrix at Lake Nabugabo, Uganda. We examined 26 births from 11 adult females over 3-years in relation to resource availability in this modified landscape, where natural foods are supplemented by crop-raiding, food-raiding, and tourist handouts. In contrast to other study sites, where vervets are classified as strict seasonal breeders (> 67% of births in 3 month period), the Nabugabo vervets are moderate seasonal breeders (33-67% of births in 3 month period). They experienced two birth peaks (May-July, and October-December), with each 3-month peak accounting for ten births (38%). Furthermore, females who had an infant that survived to 6 months of age (n=18) and who subsequently gave birth had mean interbirth intervals approximating one year (368 ± 97, range 241-550 days; n=12), which is similar to what has been reported for vervets in other locations. The reduced breeding seasonality at Nabugabo may be associated with less variation in food availability and access to energy-dense human foods, suggesting that females rely partly on internal cues (i.e., body condition) to time reproductive events.