Hominid–Carnivore Coevolution and Invasion of the Predatory Guild

Abstract

Coevolution is defined as reciprocal selective pressures that operate to make the evolution of one taxon partially dependent on the evolution another. This process often involves multiple species exploiting shared limiting resources. In classic coevolutionary models, populations of sympatric species are seen to diverge in one or more morphological, ecological, or behavioral traits to effect more even partitioning of resources and reduce levels of interspecific competition. Character displacement and resource partitioning are thought to be central not only to how species coexist on limited resources, but also to how species invade new resource niches. Hominid invasion of the predatory guild at least 2 my ago would have brought them into contact with a range of new selective pressures including competition with a number of large-bodied predators. This study explores resource partitioning between hominids and other Plio-Pleistocene large-bodied predators through analyses of predator food transport strategies. The anatomical content (head/limb MNE) of hominid transported faunal assemblages at Bed I Olduvai and FxJj 50 (Koobi Fora), when compared to modern predator control cases, suggests that Plio-Pleistocene hominids practiced food transport strategies intermediate between those of top predators such as wolves and those of confrontational scavengers such as spotted hyaenas. Plio-Pleistocene hominid food transport strategies do not resemble those of nonconfrontational scavengers such as brown and striped hyenas. The highly regular patterns differentiating bone assemblages accumulated by top predators, hominids, and confrontational and nonconfrontational scavengers suggest that hominid invasion of the predatory guild involved resource partitioning potentially based on some form of character displacement.