Intrasexual co-operation and the sex ratio in African lions.

Panthero leo in the Serengeti National Park and Ngorongoro Crater, Tanzania, live in stable social groups. The reproductive success of individuals of each sex depends on the number of like-sexed companions that they have. Males form coalitions of up to 7 individuals that act as a unit in competition against other coalitions. A successful coalition gains temporary, exclusive access to a group of females for up to several years before being ousted by another coalition. Larger coalitions are more likely to gain residence in a pride, remain in residence longer, and gain access to more females. Coalition partners seem to have similar mating success. Reproductive success of males increases with increasing coalition size. Females live in prides of 1-18 adult females; all females breed at a similar rate; females in prides of 3-10 adult females have higher individual fitness, but female fitness does not increase with group size at the same rate as occurs in males. The probability of living in a larger group as an adult depends primarily on the size of the cohort in which an individual was reared.-from Authors

Duke Scholars

Author Anne Pusey Evolutionary Anthropology