The titis and owl monkeys of South America live in socially-monogamous groups where the male and female establish a pair bond and share parental duties. Why do males of these species mate in a monogamous relationship, presumably foregoing other reproductive opportunities? Why are they such amazing fathers, investing heavily in offspring they cannot be certain they sired? Relying on ecological, behavioral, and genetic data collected over 28 years from wild populations in Argentina, Peru, and Ecuador, Professor Eduardo Fernandez-Duque discusses the role of food distribution, mate guarding, and infant care in the evolution of pair-bonds, monogamy, and paternal care. Eduardo Fernandez-Duque is Professor of Anthropology and the School of the Environment at Yale University. Trained in biological anthropology, psychology and primatology, he studies the behavioral, physiological, and ecological correlates of monogamy, pair-bonding, and parental care. His primate research in Ecuador, Perú, Argentina and the US has resulted in over 200 publications and the training of over 400 students from across the world. He is a Fellow of the American Association for the Advancement of Science and the Kavli Foundation, and a recipient of The John P. McGovern Lecture Award from the American Association for the Advancement of Science. This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at https://www.ted.com/tedx