Among non-human primates, grooming is a common practice. Research has shown that there are many underlying reasons why non-human primates groom. It is not completely altruistic or selfish but is often a resource traded for food, mating access, protection, and other social benefits. It can be used to achieve higher social rank as the bonds formed from grooming help primates climb the social ladder. There are other advantages of grooming, which include increased social bonding, mating access, and offspring support
"The Importance of Peer-to-Peer Grooming Among Non-human Primates,"
Intuition: The BYU Undergraduate Journal of Psychology: Vol. 11:
1, Article 11.
Available at: https://scholarsarchive.byu.edu/intuition/vol11/iss1/11