Spatial organization in the Ethiopian wolf Canis simensis: Large packs and small stable home ranges

The spatial organization of the rare Ethiopian wolf (Canis simensis) was Studied in the Afroalpine heathlands of Bale Mountains National Park, southern Ethiopia, between 1988 and 1992. Nineteen animals were radio-tracked, 48 ear-tagged and 64 others recognized by coat patterns and observed directly. Dry season (October-March) home ranges of resident wolves covered between 2 and 15 km-2. The ranges of adult males were slightly larger than those of females, and subadults' home ranges were slightly smaller than those of adults. The population density of the wolves was correlated with prey biomass. In optimal habitat, wolves lived in packs of 3-13 adults (mean 5-9 wolves gt 1 year old) containing several close-kin males; adult sex ratio favoured males 1.88:1 and combined pack home ranges averaged 6.0 km-2. In an area of lower prey productivity, wolves lived in pairs or small groups (mean 2.7), adult sex ratio was 1:1 and home ranges averaged 13-4km-2 cntdot Home ranges overlapped extensively (mean 85%) between members of the same pack. Four to seven percent of the population was additionally composed of non-resident females, inhabiting larger ranges (mean 11.1 km-2). Home ranges of neighbouring packs were largely discrete, forming a tessellating mosaic of packs occupying all available habitat. Pack home ranges were stable in time, drifting only during major pack readjustment after the disappearance of a pack or significant demographic changes. Ethiopian wolf home ranges were smaller than would be expected for a carnivore of its size and sociality, presumably as a result of the high rodent productivity of the Afroalpine ecosystem.