title: Introduction to special issue.
authors.affiliation: Evolutionary Anthropology School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, 85287.
authors.forename: Joan B
authors.initials: JB
authors.lastname: Silk
mesh_terms: D000818:Animals; D000885:Anthropology, Physical; D005075:Biological Evolution; D006801:Humans; D011323:Primates