Females are mature in 5 years and males at 7 years. Contrary to males, who stay in their natal group, females migrate, which insures genetic diversity. The mating system of Hamadryas baboons is the female defense polygyny. When males reach puberty, they try to fund their own group. To acquire females, males have three strategies: herding females who had recently attained sexual maturity, the follower-entry and the leader-entry strategies (Colmenares, 1992). Takeovers are generally preceded by an injury to the leader male. Infanticide following a takeover has not been reported in wild Hamadryas baboons. However, it appears that the new leader does not really defend infants. Thus, they may easily be kidnapped by other males and may die from dehydration or injury (Swedell, 2000).

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During estrus, the perineum of the females swells up. Following a takeover, females also present sexual swellings even if they are not receptive. However, interbirth intervals are not reduced. This could be a counter-strategy against infanticide (Zinner and Deschner, 2000) and explains why it has not been observed in the wild. Adoption and kidnapping could occur really more often than what was believed (Smith, Kanthaswamy, 1999). This is very surprising since these behaviors should have been selected against over the natural selection process.