Carnivoran Dispersal Out of Africa During the Early Pleistocene: Relevance for Hominins?

Abstract

Carnivorans and hominins share a long history of interactions. This paper examines some of the evidence for carnivoran migration out of Africa at the same time as the earliest hominin dispersals. Of the two relevant taxa, Crocuta and Megantereon, Megantereon is the focus of this paper due to increased interest in this taxon in recent years and to the nature of the earliest records of dispersal of these two taxa, raising several questions related to Megantereon and its possible influence on hominins. To answer these questions, a brief summary of the literature on Megantereon in Eurasia and Africa is provided. While researchers do not agree on the number of species of Megantereon or the evolutionary relationships among those species, most would agree that Megantereon is a hypercarnivorous predator capable of grappling with relatively large prey for its body size. Despite the fact that carcasses generated by Megantereon were probably of value to hominins, the hypotheses that these carcasses were a major source of food or that they were a major force enabling hominins to migrate out of Africa are rejected. As indicated in the literature on extant carnivorans, kleptoparasitism (= food theft) by dominant members of a carnivore guild exacts a heavy price on lower ranking carnivores. In addition, there is nothing in the African fossil record to suggest a special relationship between Megantereon and hominins that did not exist between hominins and other large-bodied carnivorans. The hypothesis that a species of Megantereon migrated out of Africa at roughly the same time as early hominins is also considered. While this hypothesis cannot be rejected, alternative hypotheses to explain similarities between later African and Eurasian forms of Megantereon are proposed (e.g., shared characters are due to convergence or are symplesiomorphies). In the end, the small number of diverse African species (including hominins) who disperse into Eurasia at the Plio-Pleistocene transition may have been part of a ­sweepstakes dispersal where the factors permitting (or driving) dispersal may have differed from species to species.