Social Monogamy in Free-ranging Owl Monkeys (Aotus azarai azarai) of Argentina

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

This project will examine why and how owl monkeys live in a monogamous relationship. Owl monkeys live in groups that include only one pair of reproducing adults and male owl monkeys are heavily involved in infant care, carrying the infant most of the time. Why do male owl monkeys mate in a monogamous relationship presumably foregoing other reproductive opportunities? Why are they such good fathers, investing heavily in the care of offspring they may have not even sired? The evolution of monogamy and paternal care in primates remains largely unknown, despite its profound implications for understanding human behavior. There are three possible explanations that the study will evaluate: 1- males are unable to monopolize more than one female because females are spread too far apart from each other, 2- the care and services the male provides to the female are necessary for the survival of the offspring and, 3- social monogamy occurs because of the successful guarding of mates done by males and females. A team of doctoral and undergraduate students from the USA and Argentina will collect data from 22 owl monkey groups in the forests of the Argentinean Chaco. Among other things, they will collect data on the abundance and distribution of food resources to evaluate how females distribute themselves in the forest and on infant survival to evaluate the benefits of paternal care. Finally, they will conduct experiments simulating the presence of predators and the presence of sexual competitors to evaluate how males and females may respond to a threat to their monogamous relationship. This project will make a substantial intellectual contribution to the understanding of how ecological and social factors affect the evolution of social monogamy in primates, including humans. It will also allow us to examine the differences between males and females in behavior and both parental and mating tendencies. From a more applied perspective, the long-term demographic data on owl monkeys will be useful in informing management decisions for other less well-known primate and mammal species. For example, it may be possible to model the viability of other more endangered primate populations based on the information collected from this project. The broad impacts of this project are numerous. The owl monkey project maintains collaborations with NGOs in Argentina that are responsible for educating the local people about conservation issues, as well as with national and provincial government offices. The PI has already offered (and will continue to offer) training and educational opportunities to 85 students from the US and to 84 students from seven Latin American countries, England, and Japan in situations ranging from field internship to MA and PhD dissertations. The study will continue to generate valuable biological samples that will be shared with numerous researchers and institutions. The PI is also involved in conservation activities, and he founded a conservation-related organization (of which he is scientific director) for the region. In addition, he has organized field training courses for Latin American students.