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Our hominid ancestors were eating grass for lunch, study shows.
Julia Lee-Thorp, archaeologist from University of Oxford, England, together with her colleagues, analyzed the teeth of the three-million-year-old Australopithecus bahrelghazi (literally, southern ape of Bahr el Ghazal).
A. bahrelghazali lived about 3 to 3.5 million years ago, according to the Australian Museum website.
Remains of its jaw and teeth were found in Bahr el Ghazal, Chad in 1993. The site also said that it is the first from its genus to be discovered outside southern and eastern Africa.
Lee-Thorp’s study on A. bahrelghazali’s diet appeared in the Nov. 12 online issue of the Proceedings of the National Academy of Sciences.
Apart from grasses, our ancient relatives munched on grass-like plants called sedges.
“No African great apes, including chimpanzees, eat this type of food despite the fact it grows in abundance in tropical and subtropical regions,” Lee-Thorp said in a press release.
“The only notable exception is the savannah baboon which still forages for these types of plants today. We were surprised to discover that early hominins appear to have consumed more than even the baboons,” she added.
“Australopithecus somehow made a living on the grassy savanna of Chad,” anthropologist Stanley Ambrose of the University of Illinois at Urbana–Champaign told ScienceNews.org.
“Whether it ate a lot of grass or the meat of grazing animals cannot easily be determined from this chemical analysis,” Ambrose added.
Using carbon isotopes, Lee-Thorp and her colleagues examined the teeth of A. bahrelghazali and other animals unearthed at Koro Toro, Chad.
Discovery News reported, “The researchers analyzed the carbon isotope ratios in the teeth and found the signature of a diet rich in foods derived from C4 plants.”
This form of carbon comes mostly from grasses and sedges.
The study also shows that our great great grandparents were mostly plant-eaters before they realized that eating flesh isn’t that bad—at least in Africa.
“These individuals survived in open landscapes with few trees, so apparently they could exploit not only dense woodland areas but also other environments,” according to Discovery News.
The area where A. bahrelghazali fossils were found is dry and hyper-arid, Discovery News reported. However, it used to be a network of “shallow lakes, with nearby floodplains and wooded grasslands” which might be able to provide the diet for the primates.
Lee-Thorp also said that A. bahrelghazali probably consumed “underground tubers, bulbs and stems, and papyrus” noting that primates usually have difficulty digesting grass blades.
"But as neither humans nor other primates have diets rich in animal food, and of course the hominins are not equipped as carnivores are with sharp teeth, we can assume that they ate the tropical grasses and the sedges directly," Lee-Thorp told Discovery News.
But before the study could be conclusive, her team needs to look into more fossil teeth.
But A. bahrelghazali is not the only primate with grass and sedges diet. In 2011, a study showed that Paranthropus boisei or the Nutcracker Man ate the same food. Lee-Thorp was also involved in this research.
But the Nutcracker Man is at least one million years younger than A. bahrelghazali.
Peter Ungar, anthropologist at University ofArkansas in Fayetteville, said that it appears that P. bosei are not the only primates with grass and sedges diet.
“The puzzle of early hominid food choices looks more and more complicated as we add pieces to it,” Ungar told ScienceNews.org. –KG, GMA News