Around 2 million years ago, the direct descendants of modern humans were not alone on the East African landscape. They shared the environment was another hominid, Paranthropus boisei, the first specimen of which was discovered in Tanzania in 1959 by Louis and Mary Leakey. The extinct hominid was informally dubbed "Nutcracker Man" because of its heavily enameled teeth, large jaw, and skull crest that would have anchored powerful chewing muscles. These fossil clues suggested that the diet of P. boisei consisted mainly of nuts and seeds, but recent closer examination shows that "Nutcracker Man" may not have eaten nuts at all.
Tooth Pitting
Paranthropus boisei is classified as a robust australopithecine, as opposed to the gracile australopithecines, more slender hominids that were the direct descendants of modern humans. The enormous jaw of P. boisei is unlike that of any other known hominid, which is why researchers initially thought they subsisted on a diet of hard foods. However, the first clue that something was amiss was a closer look at the teeth, which did not bear the telltale pitting seen in animals that eat mostly nuts and seeds.
Carbon Isotopes
The clincher came when scientists drilled the enamel from the teeth of 22 P. boisei fossils and analyzed the carbon isotopes within. Because different types of plants use different carbon isotopes for photosynthesis, studying the carbon isotope ratio in tooth enamel can reveal what types of plants an individual ate during its lifetime. For example, tropical grasses use both carbon-12 and carbon-13 isotopes, while trees (and their attendant nuts and fruits) use only carbon-12.
The Hominid That Ate Like a Pig
According to the analysis, the diet of Paranthropus boisei consisted almost entirely of grasses, just like the diets of the grazing animals — like the ancestors of pigs and zebras — that shared their environment. Researchers now speculate that the large jaw and skull may have aided "Nutcracker Man" in chewing the tough grasses and sedges that were their main food staple.
Interestingly, there is no modern ape whose diet approximates that of P. boisei, and even among all living primates the practice of grass-eating is unusual. The modern primate bearing the closest resemblance to the "Nutcracker Man" is the gelada baboon, which lives primarily in Ethiopia and has tooth structure and enamel wear similar to that seen on P. boisei fossils.
Sources
- Choi, Charles Q. "Human Origins: Our Crazy Family Tree." LiveScience. 9 Nov. 2009. Web. 17 May 2011.
- Choi, Charles Q. "'Nutcracker Man' Ate Like a Cow (or Pig)." LiveScience. 2 May 2011. Web. 17 May 2011.
Jenny Ashford - Jenny Ashford is a writer and graphic artist from central Florida. Her main area of interest in her Suite 101 articles is science, with a ...
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