An investigation of tooth wear in a group of wild Japanese macaques has significant associations with the study of human evolution, new University of Otago research has revealed.
As indicated in a SciTechDaily report, lead author Dr. Ian Towle and Sir John Walsh Research Institute's Dr. Carolina Loch, in partnership with colleagues from Japan, examined root grooves and large uniform scratches in the teeth of the macaques which had formerly been described in human fossils.
Uncommon wear on the teeth of fossil ancestors is thought to be "unique to humans" and exhibits certain types of tool use, explained Dr. Towle.
He added these types of wear have also been considered some of the cultural habits' earliest evidence for the ancestors.
However, he continued, their study suggests the notion may need reconsidering since they describe identical tooth wear in a group of wild monkeys that are not using tools.
This study brings out questions for their insight into cultural changes during human evolution and proposes there may be a need to reexamine early evidence of cultural habits.
'Toothpick-Like' Grooves on Macaques' Teeth
The study published in the American Journal of Biological Anthropology established the "toothpick-like" grooves on back teeth, and large uniform scratches on the front teeth of macaques resulted from something more ordinary, yet still astonishing, eating shellfish from rocks and unintentionally chewing grit and sand with their food.
This group of macaques is famous for undertaking outstanding behaviors, including washing foods in water and eating fish.
They have been investigated for over 70 years and have not been seen using tools or any other item that could cause the atypical tooth wear observed.
Dr. Towle has been examining tooth wear and pathologies in a great range of primate species and was very surprised to discover this type of tooth wear in a group of wild monkeys.
Large Scratches in Fossil Humans' Front Teeth Examined
According to a similar Phys.org report, until now, the large scratches in the fossil humans' front teeth have been considered to be caused by a behavior known as "stuff and cut," in which an item like an animal hide is held for slicing between the front teeth and a stone tool.
In a similar way, toothpick grooves are believed to be caused by tools being positioned between back teeth to eliminate food debris or ease pain.
Even though this does not mean hominins did not place tools in their mouths, this new study suggests that accidental or unintentional ingestion of grit or normal food processing behaviors could be responsible for these unique wear patterns.
The lead author believes the findings offer an understanding of how researchers are interpreting cultural changes through the period of human evolution.
Towle also explained, "We are so used to trying to prove" that humans are unique that similarities with other primates are frequently neglected. Examining today's living primates may provide crucial hints that have been overlooked in the past.
Related information about teeth and human evolution is shown on Evans EvoMorph Lab's YouTube video below:
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