Sam Diaz-Munoz: UC Berkeley Department of Plant and Microbial Biology and Integrative Biology

Tamarins (Saguinus sp) are small Neotropical monkeys that, with other callitrichines, exhibit the most extensive cooperative breeding system of any non-human primate. In this presentation, I will draw on recent studies of tamarins and other callitrichines to underscore the importance of cooperative infant care to their complex social system. I review how callitrichines were originally classified as monogamous, but instead have one of the most flexible social organizations among mammals and birds. I highlight how social organization responds to different ecological conditions and how this flexibility represents a challenge to the concept of the mating system. I suggest that the cost of infant care is a main driver of atypical sexual roles, with intense female reproductive competition and extensive cooperation among males in reproductive contexts. I discuss other species that share elements of social organization with Saguinus tamarins, including humans. Given that increasing evidence points to a cooperatively breeding past for early humans, I advocate for an increasing focus on callitrichines as study systems for understanding the evolution of cooperative behavior in humans and all animal societies.