Silver strands and greying hair is a sign of ageing in humans, but things aren’t so simple for our closest ape relatives—the chimpanzee. A new study from researchers in the Columbian College of Arts and Sciences’ Center for the Advanced Study of Human Paleobiology finds that greying hair is not indicative of a chimpanzee’s age.
This research calls into question the significance of the greying phenotype in wild non-human species. While greying is among the most salient traits a chimpanzee has—the world’s most famous chimpanzee was named David Greybeard—there is significant pigmentation variation among individuals. Greying occurs until a chimpanzee reaches midlife and then plateaus as they continue to age, said Elizabeth Tapanes, a Ph.D. candidate and lead author of a paper published in PLOS ONE on Tuesday.
“With humans, the pattern is pretty linear, and it’s progressive. You grey more as you age. With chimps that’s really not the pattern we found at all,” Ms. Tapanes said. “Chimps reach this point where they’re just a little salt and peppery, but they’re never fully grey so you can’t use it as a marker to age them.” MORE