http://www.sciencemag.org/news/2020/12/even-young-adults-male-chimps-are-mama-s-boys

Young adult male Haden, 19, grooms his mother, Lita, who is his “best friend,” at Kibale National Park in Uganda.

Even tough male chimps need their moms. Chimpanzees live in a male-dominated society, where most of their valuable allies are other males. However, as young male chimpanzees become adults, they continue to maintain tight bonds with their mothers, a new study reveals. And for about one-third of them, this mother-son relationship is the closest one they have.