Playful companions for motherless monkeys. In: Investigating Play in the 21st Century (2007)

Abstract

For some of the monkeys bonding took place with non-conspecifics that developed into lasting positive relationships. These relationships resembled children and their pets. They were initially endless bouts of chasing, wrestling and slumber parties, but as the animals matured they became long periods of just hanging out together, as favorite companions tend to do.