New Study Examines Chewing Biomechanics of Homo floresiensis | Paleoanthropology


The feeding biomechanics of Homo floresiensis, a small-bodied hominin lived until about 50,000 years ago on Flores, Indonesia, closely resembled the patterns observed in modern humans, according to new research led by Duke University’s Dr. Justin Ledogar.

Reconstruction of Homo floresiensis. Image credit: Elisabeth Daynes.

Reconstruction of Homo floresiensis. Image credit: Elisabeth Daynes.

X-ray CT scans, Dr. Ledogar and his colleagues from Italy and the United States created a 3D virtual model of the skull of Homo floresiensis.

They used computer simulations and a technique called finite element analysis to give the virtual skull characteristics that mimic the real thing, such as the stiffness of the bones and the pulling action of the muscles.

Then they had the virtual skull chomp down with its back teeth — premolars and molars — and analyzed the forces at work with each bite, essentially subjecting it to a digital crash test.

The researchers mapped the strains within their digital model of the Homo floresiensis’ facial bones during biting, comparing the results to similar simulations for australopiths that lived 2-3 million years ago in Africa, along with chimpanzees and humans living today.

They determined that the bite of Homo floresiensis could have exerted around 1,300 Newtons of force, comparable to the chomping power of modern humans and several of our extinct cousins.

But had it bitten down too vigorously on a hard nut or a tough hunk of meat, the findings suggest Homo floresiensis would have been at greater risk than our earlier human kin of straining its facial bones, or dislocating the joint where the lower and upper jaws meet.

“We don’t really know what Homo floresiensis ate,” said Rebecca Cook, a doctoral student at Duke University.

Patterns of wear on the teeth, combined with pygmy elephant bones and other animal remains unearthed from the same cave where Homo floresiensis was found suggest that it ate at least some meat.

But the results suggest that exceedingly hard or tough foods, which would have been no problem for australopiths to gnaw on or crack open, might have given Homo floresiensis a temporomandibular joint disorder (TMJ) headache.

“Similar patterns are observed in modern humans,” Cook said.

“The next step is to do similar analyses on earlier members of the genus Homo, including Homo erectus,” Dr. Ledogar said.

“The first known hominin to use fire and cook food, this species also had smaller teeth, jaws and faces than earlier hominins, and is thought by some to be the ancestor of Homo floresiensis.”

The team’s results appear in the journal Interface Focus.

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Rebecca W. Cook et al. 2021. The cranial biomechanics and feeding performance of Homo floresiensis. Interface Focus 11 (5): 20200083; doi: 10.1098/rsfs.2020.0083