Abstract: For the past decade, the idea that non-human primates avoid copulating with close kin in their social group is controversial among anthropologists, biologists and psychologists. Based on the inbreeding avoidance hypothesis, I make three assumptions: 1) Inbreeding is costly and may reduce individual reproductive fitness; 2) The costs of inbreeding outweigh its benefits; 3) If the costs are higher than the benefits, mechanisms to avoid inbreeding should evolve. In this work, I analyzed breeding data from 6 primate families and 19 populations, addressed these three assumptions and evaluated their applicability to these primate groups.

Key words: Non-human primates; Inbreeding; Social structure; Behavioral avoidance; Dispersal