Anthropological Institute & Museum, University of Zurich
Saturday 3:00-3:15, Grand Ballroom II
In general, adult-level skills must be reached before the onset of reproduction. Using a large sample of birds and mammals, we show that immatures of species with more complex foraging niches (and larger brains as adults) take longer to reach adult skill levels than those with simple niches. This indicates a strong life history constraint on the evolution of skill-intensive niches. We then ask under which conditions species can nevertheless evolve into high-skill foraging niches, and distinguish two distinct, but non-exclusive pathways. First, among primates and other non-provisioning mammals, complex niches and large brains are found in lineages with extremely slow somatic development, which buys time for skill learning. Second, we show that immatures in other species with more complex foraging niches are supported through provisioning in the post-weaning or post-fledging period. Indeed, in cooperatively hunting species, adult skill levels can be reached well after the onset of reproduction. Humans are unique among primates in reaching adult skill levels well after reproductive maturity. This analysis shows that the evolution of our species’ complex foraging niche was made possible because our ancestors, with extremely slow development due to their great ape ancestry, began to provide energetic support not only to mothers, but also to weaned immatures, as we evolved cooperative breeding and hunting.