Neotropical Primates 13(3), December 2005

Male reproductive success in nonhuman primates has traditionally been measured by access to estrous females, and successful matings/inseminations are attributed either to high-ranking males in multi-male groups or to the one male in a single-male group (e.g., Fedigan, 1983; Smuts, 1987; Dixson et al., 1993; Paul et al., 1993). Paternity exclusion techniques and the testing of potential fathers and infants, however, have demonstrated that access, including copulation, does not always correlate with success. As group size increases, there are more females for the highest-ranking male to inseminate, and if the females are seasonal or synchronous breeders, the male is less able monopolize estrous females (Nunn, 1999; Takahashi, 2001). The discrepancy between dominance rank and mating success involves more than female availability, however. In single-male patas monkey groups, the resident male did not sire all offspring (Ohsawa et al., 1993), and alternate male strategies in multi-male groups are known from rhesus monkeys (Berard et al., 1993, 1994, 1999; Smith, 1993, 1994) and savannah baboons (Alberts et al., 2003) which allow for reproductive success in lower-ranking males.