It’s tempting to argue that only H. erectus, which had a brain approaching twice the average size of P. boisei ’s, could have made teardrop-shaped, double-edged hand axes that date to around the same time as the two hominids. Those tools demanded more skill and planning than earlier, simpler cutting implements.
The first hand, arm and shoulder fossils found from the same Paranthropus boisei individual were excavated in Kenya. These finds indicate that this ancient hominid combined powerful arms with a hand grip capable of at least simple stone-tool making.
P. boisei, a distant cousin to modern humans, lacked a thick, powerfully gripping thumb characteristic of its hominid contemporary, Homo erectus ( SN: 3/24/15 ), a prolific maker of sophisticated stone tools. But the newly described hand bones suggest that P. boisei gripped well-enough to make and use simple stone and bone tools, ...
A large male skull discovered in 1959 is the best-known P. boisei fossil. Dubbed Nutcracker Man, the individual has wide cheekbones that project forward and a bony crest atop its braincase that once anchored huge chewing muscles.
It’s not hard to understand why Paranthropus boisei is often called the Nutcracker Man. The hominid’s massive molars and enormous jaw make it seem pretty obvious that the species spent a lot of time chomping on hard nuts and seeds. Yet, the only direct evidence of P. boisei ‘s meals—the chemistry and microscopic scratches of the teeth—hint that the species probably didn’t crack nuts all that much, instead preferring the taste of grass. A team of anthropologists that recently reviewed the possible diets of several early hominid species has highlighted this paradox of the Nutcracker Man and the difficulties in reconstructing the diets of our ancient kin.
Then they look for modern primates that have similar-looking dentition to see what they eat. For example, monkeys that eat a lot of leaves have molars with sharp cusps for shearing the tough foliage. On the other hand, monkeys that eat a lot of fruit have low, rounded molar cusps. If you found a hominid with either of those traits, you’d have a starting point for what the species ate.
The species’ giant, thickly enameled molars and premolars (better known as bicuspids) and heavy jaw suggest P. robustus was chewing hard objects. The surface wear on the teeth also point to eating hard foods and resemble the wear patterns seen in modern mangabey monkeys, which often eat nuts. The teeth’s enamel chemistry further supports this conclusion: As much as 60 percent of the species’ diet consisted of C3 plants, which would include hard-shelled nuts and fruits (carbon chemistry can’t detect which part of a plant an animal ate).