Kevin Langergraber received his Ph.D. from the Department of Anthropology in 2007. Aaron Sandel received his Ph.D. from Anthropology in 2017.

Newswise — AUSTIN, Texas — Although they have no way of identifying their biological fathers, male chimpanzees form intimate bonds with them, a finding that questions the idea of fatherhood in some of humanity’s closest relatives, according to a study of wild chimpanzees in Uganda.

In adulthood, male chimpanzees form strong relationships with one another. These bonds can be mutually beneficial — to relieve stress, protect one another and share food. In a new study examining when and with whom these bonds develop, researchers found chimpanzees most often bond with their maternal brothers and old males, including — seemingly unbeknownst to the younger chimps — their biological fathers.

“Fatherhood is really a social relationship that happens to be linked to a genetic relationship. In humans, it is strongly correlated because humans tend to form pair bonds,” said Aaron Sandel, assistant professor of anthropology at The University of Texas at Austin. “Usually we think that pair bonds evolved in humans first, and then fathers came to play an active role. However, my findings suggest that elements of fatherhood may have arisen in a chimpanzee-like social system before mates formed pair bonds.”