Versatility in hominin diets

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES—Researchers report* isotopic evidence of habitats and diets of two early hominin species, showing that both species were dietary generalists and displayed adaptability to a wide range of paleoenvironmental conditions. Around 2.4 million years ago, Paranthropus boisei and Homo rudolfensis coexisted in the southern East African Rift system, although their diets and paleoenvironmental adaptations were not known. Tina Lüdecke and colleagues used carbon and oxygen isotope data from hominin tooth enamel, as well as contemporaneous equid and bovid animals, to investigate the hominins’ diet and reconstruct their paleoenvironments. Clumped isotope data from soils at the hominin fossil sites additionally enabled temperature reconstruction of the region. The results suggest that both hominin species were likely adapted to C3 plants [most common and the most efficient at photosynthesis in cool, wet climates, like woody trees and beans] and lived in relatively cool and wet wooded savannas near ancient Lake Malawi. Paranthropus fossils found in dry open grassland regions of Africa’s Eastern Rift exhibited consumption of C4 plants [most efficient at photosynthesis in hot, sunny climates, like grasses and some shrubs], with the distinction in diets between the two regions becoming enhanced around 2 million years ago, when the savanna became more open than before. According to the authors, the results suggest a high degree of versatility in the ability of Homo and Paranthropus to adapt and thrive in a variety of environmental conditions.

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Fossil tooth enamel of Homo rudolfensis has been analyzed to reconstruct its diet. Image courtesy of Oliver Sandrock.

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