Addax
Weight:
Female Ethiopian wolves average 12.8 kg (11.2 - 14.2 kg) (average 28.2 lb (24.6 - 31.2 lb)); males average 16.2 kg (14.0 - 19.3 kg) (average 35.6 lb (30.8 - 42.5 lb)).
Habitat:
The Ethiopian wolf is a localized endemic species and is confined to isolated pockets of grasslands and heathlands, where it preys on rodents. Rodent biomass varies several-fold between different habitats, and the abundance of these prey is closely correlated with that of the wolves, which appear to utilize all suitable habitat. The Ethiopian wolf is found above 3000 m (10,000'). It prefers areas with short vegetation less than 0.24 m (10") high. (Sillero-Zubiri & Macdonald 1997)
The Ethiopian wolf occurs in the Ethiopian Highlands Global 200 Ecoregion. (Olson & Dinerstein 1998, Olson & Dinerstein 1999)
Age to Maturity:
Both sexes mature during their second year.
Gestation Period:
Approximately 60 days.
Birth Season:
October - December.
Birth Rate:
2 - 6 pups per litter.
Females breed no more than once a year. Only about 60% of dominant females breed successfully each year (Sillero-Zubiri & Macdonald 1997).
Early Development:
Development of the young is divisible into three stages: 1) early nesting (week 1 to week 4), when the young are entirely dependent on milk; 2) mixed nutritional dependency (week 5 to week 10), when milk is supplemented by solid foods regurgitated by all pack members until pups are completely weaned; and 3) post-weaning dependency (week 10 to 6 months), when the pups subsist almost entirely on solid foods supplied by helpers. (Sillero-Zubiri & Macdonald 1997)
Dispersal:
Dispersal movements are tightly constrained by the scarcity of suitable unoccupied habitat. Males do not disperse; two-thirds of the females disperse at two years of age and become "floaters", occupying narrow ranges between pack territories until a breeding vacancy becomes available. Breeding females typically are replaced after death by a resident daughter. This results in a high potential for inbreeding which may be circumvented via inter-pack mating. (Sillero-Zubiri & Macdonald 1997)
Diet:
Analysis of fecal samples in one study revealed that rodents account for 96% of all prey (Sillero-Zubiri & Macdonald 1997). The endemic giant mole rat (Tachyoryctes macrocephalus) is the main food item; other prey includes grass rats and hares. In the Afro-alpine meadows of Bale Mountain National Park, rodent biomass was estimated at 3 - 4000 kg/sq km (27 - 36 lb/acre) (Gottelli & Sillero-Zubiri 1992).
Behavior:
Ethiopian wolves are most active during the day; peaks of foraging activity suggest that they synchronize their activity with that of rodents above the ground. Digging prey out is common. Kills are often cached and later retrieved. Although the Ethiopian wolf is a pre-eminent rodent hunter on its own, it can also be a cooperative hunter. Occasionally, small packs have been seen chasing and killing young antelopes, lambs, and hares. Wolves congregate for social greetings and border patrols at dawn, noon and evenings, and rest together at night, in the open. They break up to forage individually in the morning and early afternoon. In Bale, there is little nocturnal activity, with wolves seldom moving far from their evening resting site. They may become more crepuscular and nocturnal where human interference is severe. (Sillero-Zubiri & Macdonald 1997)
Pups are born in a den dug by the female in open ground, under a boulder or inside a rocky crevice. Pups are regularly shifted between dens, up to 1300 m (4300') apart. (Sillero-Zubiri & Macdonald 1997) Dens usually consist of a much-used system of burrows beneath a rock overhang or cliffs; other burrows located in a flat, grassy area have several entrances, possibly interconnected (Ginsberg & Macdonald 1990).
Social Organization:
Although Ethiopian wolves live in packs that share and defend an exclusive territory, for the most part they forage and feed alone on small rodent prey, in contrast to the general association in larger carnivores between grouping and cooperative hunting. In optimal habitat, packs consist of 3 - 13 adults (average = 6). A typical pack is an extended family group formed by all males born into the pack during consecutive years and 1 - 2 females.
During the breeding season, social gatherings are more common and take place next to the den. Aggressive interactions with neighboring packs are common. The interactions are highly vocal and always end with the smaller group fleeing from the larger. Home range overlap and aggressive encounters between packs are highest during the mating season. Courtship may take place between adult members of a pack or with members of neighboring packs. Mate preference within a pack is shown, with the female discouraging attempts from all but the pack's dominant male. In contrast, she is receptive to any visiting male from a neighboring pack. Up to 70% of matings involve males from outside the pack. All pack members guard the den, chase potential predators, and regurgitate or carry rodent prey to feed the pups. Subordinate females may assist the dominant female in suckling the pups. (Sillero-Zubiri & Macdonald 1997)
Age & Gender Distribution:
In optimal habitat, pack adult sex ratio was biased toward males by a ratio of 2.6:1. In an area of lower prey productivity, the adult sex ratio was 1:1. (Sillero-Zubiri & Macdonald 1997)
Density/Range:
The highest population density was perhaps 2 individuals/sq km (5.2 individuals/sq mi) (Nowak & Paradiso 1983).
Annual home ranges of eight packs in optimal habitat monitored for four years averaged 6.4 sq km (2.5 sq mi), and home ranges in an area of lower prey biomass averaged 13.4 sq km (5.2 sq mi), with some overlap between home ranges. An additional 4-7% of the population was composed of non-resident females, inhabiting larger ranges (average 11.1 sq km (4.3 sq mi)). Home ranges of neighboring packs were largely discrete, forming a mosaic of packs occupying all available habitat. Pack home ranges were stable in time, shifting only during major pack readjustment after the disappearance of a pack or significant demographic changes. (Sillero-Zubiri & Macdonald 1997)