Abstract:
A clan of spotted hyaenas was studied for 27 months in the Kruger National Park with the purpose of describing its structure, social organization and members' dispersal patterns, and to relate these to resource procurement, environmental factors, prey selection, spatial organization and diet. Five social classes were recognized within a clan, namely, females, cubs, resident natal males, a central immigrant male and peripheral immigrant males. The clan was organized in a linear dominance hierarchy, which was most strongly expressed at food to the benefit of dominant individuals. Females were philopatric, dominant to males and maintained amicable relationships amongst each other and their offspring. Males emigrated, joining adjacent clans, where they had precarious social relationships, except a central immigrant male, which attended females closely and gained unrivalled breeding status. Different key resources for each sex explain ecological differences, especially foraging behaviour, interspecific interactions, territory defence, space utilisation and food consumption. Events that preceded the decline of the study clan in month 24 indicated that the lack of litter synchrony necessary for communal denning, may have led to high cub mortality and failure to compensate for natural adult mortalities. This could be a fortuitous result of earlier culling in the area. Foraging behaviour was opportunistic, explaining small group size. Most carcasses were scavenged, often after interacting with other carnivores. While occasional harassment of large prey could sporadically enable hyaenas to kill, their hunting behaviour concentrated on vulnerable ungulate species of medium size, indicating an ability to discriminate between more and less profitable potential food sources. The 130km 2 territory was intensively patrolled and scent marked, but its defence depended on the presence of resident females. Regional differences in prey abundance, vulnerability and lion activity strongly influenced hyaena space utilization and resulted in patchy food distribution, which could have determined territory size. Various techniques of diet determination were compared. Although scavenged carcasses of very large ungulates, particularly buffalo, contributed heavily to hyaena diet, occasional killing by hyaenas, especially of more vulnerable medium-sized ungulates was essential, a pattern that was evident throughout the Kruger National Park.
