Eduardo Fernandez-Duque: Yale University

I will discuss published and new data from a population of monogamous owl monkeys in the Argentinean Chaco that we have been studying for almost 20 years to examine the hypothesis that social monogamy is a default social system imposed upon males because the spatial and/or temporal distribution of resources and females makes it difficult for a single male to defend access to more than one mate. Over the years we have tested predictions on ranging patterns, use of space, population density and the abundance and distribution of food. We have also examined the extent to which the ranging and ecological data allow us to predict demographic and life-history parameters as proxies for reproductive success.