December 1, 2023

Strange Tooth Discovery Prompts Rethink of Human Evolution

” However, our research study suggests this concept might need reassessing, because we explain identical tooth wear in a group of wild monkeys that do not use tools.
” This research raises questions for our understanding of cultural modifications throughout human advancement and suggests we may need to reassess early evidence of cultural routines.”
Koshima Island macaque removing limpets.Credit: Cecile Sarabian
The study, released in the American Journal of Biological Anthropology, concluded the toothpick- like grooves on back teeth and big uniform scratches on the macaques front teeth were actually triggered by something more ordinary, yet still surprising– eating shellfish from rocks and mistakenly chewing grit and sand with their food.
This macaque group is well-known for undertaking remarkable behaviors, consisting of washing foods in water, and consuming fish. They have actually been studied for more than 70 years and have not been seen using tools or other items that could cause the uncommon tooth wear observed.
Dr. Towle has been studying tooth wear and pathologies in a variety of primate species and was “incredibly shocked” to discover this type of tooth wear in a group of wild monkeys.
Koshima Island macaque consuming limpets. Credit: Takafumi Suzumura
” Up till now, the big scratches in the front teeth of fossil human beings have been thought about to be triggered by a behavior called things and cut, in which a product such as an animal hide is held between the front teeth and a stone tool is utilized for slicing. Likewise, toothpick grooves are thought to be triggered by tools being positioned between back teeth to eliminate food debris or alleviate pain.
” Although this does not indicate hominins were not placing tools in their mouths, our study suggests the unexpected consumption of grit and/or regular food processing behaviors could likewise be accountable for these atypical wear patterns.”
Dr. Towle thinks the findings offer insight into how researchers analyze cultural modifications through the course of human evolution.
” We are so utilized to attempting to show that humans are distinct, that resemblances with other primates are typically neglected. Studying living primates today may provide important clues that have actually been neglected in the past.”
Reference: “Atypical tooth wear discovered in fossil hominins also present in a Japanese macaque population” by Ian Towle, Andrew J. J. MacIntosh, Kazuha Hirata, Mugino O. Kubo and Carolina Loch, 1 March 2022, American Journal of Biological Anthropology.DOI: 10.1002/ ajpa.24500.

Koshima Island macaque (left) and Neandertal (right), both upper central incisors showing large vertical scratches. Credit: Ian Towle and John C. Willman.
A research study into tooth wear in a group of wild Japanese macaques has substantial implications for the study of human development, a University of Otago research study has revealed.
Lead author Dr. Ian Towle and Dr. Carolina Loch, of the Sir John Walsh Research Institute, in collaboration with associates from Japan, studied root grooves and big uniform scratches in the macaques teeth, which had formerly just been described in fossil people.
” Unusual wear on our fossil forefathers teeth is believed to be distinct to humans and shows particular kinds of tool usage. These kinds of wear have also been considered a few of the earliest evidence of cultural routines for our forefathers,” Dr. Towle states.