Grooming rituals are very common in macaques. Grooming not only keeps monkeys healthy, but it also reinforces social structures and bonds between animals. In this photo, a male macaque named Mario is grooming a female macaque named Gao-luck.

[Photo and caption by Nalina Aiempichitkijkarn]

Reference:

Henazi, S. P., & Barrett, L. (1999). The value of grooming to female primates. Primates, 40(1), 47-59.

[Edited by Maggie Creamer]