Spider monkey are one of a handful of mammalian species that live in social groups that display "fission-fusion" dynamics, where group members break into small parties of variable and changing composition for daily foraging and travel. An individual animal's decisions about when to associate with other group members and with whom to associate are thought to be influenced by a number of socioecological factors, including the availability of food resources and the risk of predation in the habitat, the animal's own reproductive status and that of other group members, and the animal's genetic relatedness to other individuals in its social group. This project will investigate the relative influence of these different classes of variables on the grouping patterns of white-bellied spider monkeys using a combination of observational data collected in Yasuni National Park, Ecuador as well as genetic and hormonal data on gleaned from noninvasively collected samples.
The study will contribute to further understanding of the principles underlying the evolution of grouping patterns in primates and other mammals. Assuming that similar general biological principles apply, then an elucidation of the factors influencing flexible grouping patterns in spider monkeys will help us identify the social and ecological conditions that are shared amongst different groups of mammals that live in fission-fusion systems (e.g., dolphins, elephants, hyenas). Additionally, the study will contribute to an understanding of the evolution of human social behavior as spider monkeys are behaviorally and ecologically convergent with chimpanzees, the nonhuman primate which currently provides the closest living analogs for the behavior of the earliest hominins. Spider monkeys and chimpanzees share a variety of characteristics of social organization, including male philopatry, female dispersal, and strong male-male associations flexible subgrouping associations, in addition to their convergent flexible social associations.
This will contribute to an ongoing long-term investigation on the comparative behavioral biology of sympatric Amazonian primates at the Tiputini Biodiversity Station in Ecuador and assist in efforts at protecting forested areas in the Ecuadorian Amazon. Additionally, it will help to strengthen the collaborations between local researchers in Ecuador and Colombia and institutions in the United States. The extension of this project (Proyecto Primates Ecuador) into other field sites in the neotropics has recently started through the launch of Proyecto Primates Colombia. In both Ecuador and Colombia, Proyecto Primates has provided the opportunity to multiple students and young professionals to build on their field experience and gain expertise in the behavioral and ecological sciences.
