You may have experienced a sore or clicking jaw when you chewed hard food or chewed gum.
This is according to a Duke University study on the chewing mechanics and habits of an ancient human relative, Homo Floresiensis. It inhabited Flores in Indonesia before we arrived there about 50,000 years ago.
The hominin is only three feet tall. Its small stature earned it the nickname "the Hobbit", after J.R.R. Tolkien's "The Lord of the Rings." The new study was published in Interface Focus on Aug. 13. It examines how the Hobbit's skull reacts to its food.
Its skull, the only one so far found, had been damaged and disfigured by thousands of years of fossilization. It had to be restored to its original form before the researchers could check it out. The University of Bologna in Italy created a virtual 3D model from X-ray CT scans. They digitally filled in the missing pieces to reconstruct the skull of Homo Florensis when it was roaming the island around 100,000 to 60,000 year ago.
They then used computer simulations and finite element analysis to create virtual skull characteristics that closely resemble the real thing. This included the stiffness of bones and pulling action of muscles. They then had the virtual skull chew down with its back teeth, premolars, and molars. Then they analyzed the forces at play with each bite, basically giving it a digital crash test.
Researchers mapped the strains in the digital model of Hobbit's facial bone structure during biting. They compared the results with simulations for human relatives, called australopiths, that were created around two to three millions years ago in Africa.
Computer simulation of a Homo Florensis cranium shows how stress and strain are displayed in the bones of the face while biting. The areas that are subject to high strain are highlighted in red, pink, and white. Credit: Ledogar lab, Duke University
The Hobbit could have exerted approximately 1300 Newtons of force when it bit down on a hard nut or hunk of meat, which is comparable to modern humans' chomping power and that of many of our extinct relatives. The findings show that Homo Florensis could have suffered more injuries if it had bitten too hard on a hard nut, or a hard chunk of meat.
Rebecca Cook, a Duke doctoral student in evolutionary anthrology, said that "we don't know what Homo Florensis ate." The patterns of wear on the teeth and the pygmy elephant bones, as well as other remains from animal remains found in the cave where the Hobbit was discovered, suggest that it probably ate some meat.
The results show that the Hobbit might have suffered from TMJ problems if he had been exposed to extremely hard or difficult foods.
Cook stated that similar patterns can be observed in modern people.
Human evolution over millions of years has resulted in smaller teeth and lighter skulls. This was because we were able to cook our food, pound it with stone tools and eat meat without having to have large skulls.
The Hobbit's facial features have remained a mystery for years. The skull of the Hobbit had many interesting traits. Some, like its large, heavy jaw, were similar to our ancestors who were more ape-like, while others, such as its delicate, small face, resemble human today.
Cook stated that this can be confusing because it is not clear where the species belongs on the evolutionary tree of hominin family relationships.
This new study shows that the shift to smaller faces and weaker bites, as well as achey jaws, was early in human evolution, long before modern humans and Homo floresiensis were separated.
Justin Ledogar is a Duke researcher and the senior author of this study. He says that the next step will be to perform similar analyses on Homo erectus and earlier members of the Homo genus. This species was the first hominin to use fire to cook food. It also had smaller jaws, teeth, and faces than other hominins. Some believe it to be the ancestor to Homo floresiensis.
According to the researchers, the research could answer some of the lingering questions about Homo Floresiensis' origin, its life and where it fits in the human evolutionary tree.
Cook stated that "this study is only one piece of a larger puzzle."
Continue reading to discover the origins of Indonesian hobbits
Additional information: Rebecca W. Cook and colleagues, The cranial biomechanics of Homo species floresiensis and its feeding performance, Interface Focus (2021). Rebecca W. Cook and colleagues, The cranial biomechanics of Homo Florisiensis's feeding performance, (2021). DOI: 10.1098/rsfs.2020.0083
