Non-Analog Behaviour of Eastern African Herbivore Communities During the Last Glacial Period.

Modern African ungulates navigate seasonal variation in resource availability through diet-switching (primarily mixed-feeders) and/or migrating (primarily grass grazers). These ecological generalisations are well-documented today, but the extent to which they apply to the non-analog ecosystems of the Pleistocene are unclear. Drawing from serially-sampled stable isotope measurements from 18 Kenyan large herbivore species from the Last Glacial Period (LGP), we evaluate how diet, diet-switching, and migration compare to observations from present-day settings.

Limited herbivore migration during the Last Glacial Period of Kenya.

Eastern Africa is home to the largest terrestrial migrations on Earth. Though these migratory systems have been well studied for decades, little is known of their antiquity and evolutionary history. Serially sampled strontium stable isotopes (Sr/Sr) from tooth enamel can be used to track migration in mammals.

Adaptive foraging behaviours in the Horn of Africa during Toba supereruption.

Although modern humans left Africa multiple times over 100,000 years ago, those broadly ancestral to non-Africans dispersed less than 100,000 years ago. Most models hold that these events occurred through green corridors created during humid periods because arid intervals constrained population movements. Here we report an archaeological site-Shinfa-Metema 1, in the lowlands of northwest Ethiopia, with Youngest Toba Tuff cryptotephra dated to around 74,000 years ago-that provides early and rare evidence of intensive riverine-based foraging aided by the likely adoption of the bow and arrow.

Environmental context shapes the relationship between grass consumption and body size in African herbivore communities.

Though herbivore grass dependence has been shown to increase with body size across herbivore species, it is unclear whether this relationship holds at the community level. Here we evaluate whether grass consumption scales positively with body size within African large mammalian herbivore communities and how this relationship varies with environmental context. We used stable carbon isotope and community occurrence data to investigate how grass dependence scales with body size within 23 savanna herbivore communities throughout eastern and central Africa.

Paleoecological evidence for environmental specialization in Paranthropus boisei compared to early Homo.

Since the discovery of Paranthropus boisei alongside early Homo at Olduvai Gorge and East Turkana, paleoanthropologists have attempted to understand the different evolutionary paths of these two hominin lineages. Conventional wisdom is that their prolonged phase of sympatry in eastern Africa reflects different adaptive strategies, with early Homo characterized as the ecologically flexible generalist and Paranthropus as the less versatile specialist. If correct, this should imply differences in their use of ancient environments, with early Homo occurring in a broader range of environmental contexts than Paranthropus.

Comparative isotopic evidence from East Turkana supports a dietary shift within the genus Homo.

It has been suggested that a shift in diet is one of the key adaptations that distinguishes the genus Homo from earlier hominins, but recent stable isotopic analyses of fossils attributed to Homo in the Turkana Basin show an increase in the consumption of C resources circa 1.65 million years ago, significantly after the earliest evidence for Homo in the eastern African fossil record. These data are consistent with ingesting more C plants, more animal tissues of C herbivores, or both, but it is also possible that this change reflects factors unrelated to changes in the palaeobiology of the genus Homo.