Hybrid Baboons and the Origins of the Hamadryas Male Reproductive Strategy

Abstract

Hamadryas male baboons concentrate their reproductive effort on a small subset of females (i.e., females in their one-male unit) rather than competing with other males for estrous females throughout the group. Hamadryas males also exhibit a sustained, intense interest in females, regardless of estrus condition, an interest manifested by stereotypical herding behaviors. In this chapter, I use the behavioral variation expressed by hybrid (olive × hamadryas) baboon males to test predictions regarding behavioral precursors of the unique hamadryas male reproductive strategy. I analyze three potential precursors for hamadryas male behavior: (1) the herding of females during intergroup encounters, (2) the long-term bonds involving paternal care (i.e., “friendships”), and (3) temporary consortships. Because the male motivation behind each potential precursor is different (intolerance of other males, paternal care, and attraction to females, respectively), it is possible to make different predictions for the behavior of hybrid males. Consort behavior of hybrid males continued over a longer portion of female estrus than is usual for nonhamadryas baboons, and nonconsort behavior of hybrid males resembled the consort behavior of nonhamadryas males. Herding females and paternal care were rare, while all hybrid males expressed some interest in nonestrous females. Results support hypothesis 3, that consortships represent the behavioral homologue to the hamadryas male reproductive strategy.