https://phys.org/news/2018-10-chimpanzees-react-faster-cooperate-selfish.html

For decades, social scientists and biologists have sought to study primates because they are humans' closest living relatives. Chimpanzees can also be very cooperative in the wild—forming alliances with friends or hunting together in groups.

"Chimpanzees are an important comparative model for human cooperation," said Alexandra Rosati, U-M assistant professor of psychology and anthropology.