ABSTRACT
This chapter is about sibling relationships that are developed by members of various nonhuman primate species. Most nonhuman primate infants grow up in the company of older siblings, and as these infants grow older they usually acquire younger siblings as well. Interactions with siblings constitute one major source of social stimulation for most monkeys and apes, at least until they are adolescents, and in some cases relationships with siblings continue to thrive throughout the whole of their adult lives.
