Role of musth in the reproductive strategy of the African elephant (Loxodonta a/ricana)

Behavioural and endrocrin%gical data on African elephants (Loxodonta africana) are integrated to provide a hypothesis oj the adaptations reflected in the phenomenon of musth in bulls. Occupation oj home ranges, movements. male dominance hierarchies and intra-specific agonistic behaviour are reviewed. Bulls in musth leave their home range, travel far and jast, initiate more contacts with distant breeding herds, show aggression which overrides normal social male hierarchies, probably mate more frequentIy than non-musth bulls and then return to their home frInge. This behaviour is associated with elevated levels of serum testosterone and dihydrotestosterone. Elephants normally show a high degree of fidelity to sexually segregated adjOining home ranges, which results in regular contact between the same bulls and cows. This breeding strategy is applicable to older, dominant bulls within the locally resident hierorchy. The musth adaptation is a second strategy, whereby younger, lower ranking bulls (25-35 years) can ensure more contacts with cows and maximize their chances of breeding. Because musth bulls mate far from their normal ranges the strategy promotes gene flow and ensuIPS outbreeding.