Primate Teeth Study Raises Questions About Hominins' Use of “Toothpicks”

MELBOURNE, AUSTRALIA—Grooves sometimes observed on the exposed roots of hominin teeth have long been interpreted as possible evidence of the use of sticks or fibers to clean teeth and gums. According to a report in The Conversation, similar grooves have been identified on the teeth of wild primates by a team of scientists led by Ian Towle of Monash University. The researchers analyzed more than 500 teeth from 27 living and extinct primate species—including gorillas, orangutans, macaques, colobus monkeys, and fossil apes—using microscopes, 3D scans, and tissue-loss measurements. Lesions were detected on about four percent of these wild primate teeth. Towle said that some of the lesions looked like “toothpick grooves,” with fine parallel scratches and tapering shapes. Shallow, smooth lesions, especially found on the front teeth, are thought to have been caused by eating acidic fruits. Towle and his colleagues suggest that wear from abrasive foods and grit—and even stripping vegetation with the teeth—could have produced the marks. Read the original scholarly article about this research in the American Journal of Biological Anthropology. To read more about comparisons between primate and hominin species, go to "Your Face: Punching Bag or Spandrel?"