INCEST AVOIDANCE AND ATTAINMENT OF DOMINANCE BY FEMALES IN A CAPE MOUNTAIN ZEBRA (EQUUS-ZEBRA ZEBRA) POPULATION

The mating strategies employed by Cape Mountain zebra and the routes by which dominance are attained by females are described. Both sexes tend to join non-breeding groups, males joining groups containing familiar males, females joining groups with male strangers. The nuclei of new herds are formed by long-term attachments between colts and fillies within these groups, the first filly forming such an attachment becoming the subsequent dominant mare. Fillies not joining non-breeding groups become subordinates in established breeding herds. For established mares only herd change on loss of the stallion may lead to status improvement. The reproductive success of the three main strategies employed by mares (attachment, herd change and direct annexation) did not differ and showed little deviation from expected reproductive success based on population fecundity. Only the first two strategies led to dominant status which is correlated with high fitness based on foal survival. Dominance for fillies was dependent on the presence of unattached colts with which they could form new breeding herds and was age-related within a female cohort, the oldest female forming an attachment first. Two forms of familiarity resulting in a repulsion towards male relatives followed in ontogeny by an attraction to male strangers are postulated as regulating the social associations of fillies. Evidence is pur forward that mate choice operates amongst females.