 Social behaviour is influenced by the climate and geography ; as such , the impala are territorial at certain times of the year and gregarious at other times , and the length of these periods can vary broadly among populations . For instance , populations in southern Africa display territorial behaviour only during the few months of the rut , whereas in eastern African populations , territoriality is relatively minimal despite a protracted mating season . Moreover , territorial males often tolerate bachelors , and may even alternate between bachelorhood and territoriality at different times of the year . A study of impala in the Serengeti National Park showed that in 94 % of the males , territoriality was observed for less than four months . 
