Ethiopian wolf

Naming

Alternative English names for the Ethiopian wolf include Abyssinian wolf, Simien fox, Simien jackal, Ethiopian jackal, red fox, red jackal, Abyssinian dog and cuberow.

Historical account

The earliest written reference to the species comes from Solinus's Collectanea rerum memorabilium from the third century AD:

The species was first scientifically described in 1835 by Eduard Rüppell, who provided a skull for the British Museum. European writers traveling in Ethiopia during the mid-19th century (then called Abyssinia) wrote that the animal's skin was never worn by natives, as it was popularly believed that the wearer would die should any wolf hairs enter an open wound, while Charles Darwin hypothesised that the species gave rise to greyhounds. Since then, it was scarcely heard of in Europe up until the early 20th century, when several skins were shipped to England by Major Percy Horace Gordon Powell-Cotton during his travels in Abyssinia.

The Ethiopian wolf was recognised as requiring protection in 1938, and received it in 1974. The first in-depth studies on the species occurred in the 1980s with the onset of the American-sponsored Bale Mountains Research Project. Ethiopian wolf populations in the Bale Mountains National Park were negatively affected by the political unrest of the Ethiopian Civil War, though the critical state of the species was revealed during the early 1990s after a combination of shooting and a severe rabies epidemic decimated most packs studied in the Web Valley and Sanetti Plateau. In response, the IUCN reclassified the species from endangered to critically endangered in 1994. The IUCN/SSC Canid Specialist Group advocated a three-front strategy of education, wolf population monitoring, and rabies control in domestic dogs. The establishment of the Ethiopian Wolf Conservation Programme in Bale soon followed in 1995 by Oxford University, in conjunction with the Ethiopian Wildlife Conservation Authority (EWCA).

Soon after, a further wolf population was discovered in the Central Highlands. Elsewhere, information on Ethiopian wolves remained scarce; although first described in 1835 as living in the Simien Mountains, the paucity of information stemming from that area indicated that the species was likely declining there, while reports from the Gojjam plateau were a century out of date. Wolves were recorded in the Arsi Mountains since the early 20th century, and in the Bale Mountains in the late 1950s. The status of the Ethiopian wolf was reassessed in the late 1990s, following improvements in travel conditions into northern Ethiopia. The surveys taken revealed local extinctions in Mount Choqa, Gojjam, and in every northern Afroalpine region where agriculture is well developed and human pressure acute. This revelation stressed the importance of the Bale Mountains wolf populations for the species' long-term survival, as well as the need to protect other surviving populations. A decade after the rabies outbreak, the Bale populations had fully recovered to pre-epizootic levels, prompting the species' downlisting to endangered in 2004, though it still remains the world's rarest canid, and Africa's most endangered carnivore.

Taxonomy and evolution

Although fossil records exist of wolf-like canids from Late Pleistocene Eurasia, no fossil records are known for the Ethiopian wolf. In 1994, a mitochondrial DNA analysis showed a closer relationship to the gray wolf and the coyote than to other African canids, and C. simensis may be an evolutionary relic of a gray wolf-like ancestor's past invasion of northern Africa from Eurasia.

Due to the high density of rodents in their new Afroalpine habitat, the ancestors of the Ethiopian wolf gradually developed into specialised rodent hunters. This specialisation is reflected in the animal's skull morphology, with its very elongated head, long jaw, and widely spaced teeth. During this period, the species likely attained its highest abundance, and had a relatively continuous distribution. This changed about 15,000 years ago with the onset of the current interglacial, which caused the species' Afroalpine habitat to fragment, thus isolating Ethiopian wolf populations from each other.

The Ethiopian wolf is one of five Canis species present in Africa, and is readily distinguishable from jackals by its larger size, relatively longer legs, distinct reddish coat, and white markings. John Edward Gray and Glover Morrill Allen originally classified the species under a separate genus, Simenia, and Oscar Neumann considered it to be "only an exaggerated fox". Juliet Clutton-Brock refuted the separate genus in favour of placing the species in the genus Canis, upon noting cranial similarities with the side-striped jackal.

In 2015, a study of mitochondrial genome sequences and whole genome nuclear sequences of African and Eurasian canids indicated that extant wolf-like canids have colonised Africa from Eurasia at least five times throughout the Pliocene and Pleistocene, which is consistent with fossil evidence suggesting that much of African canid fauna diversity resulted from the immigration of Eurasian ancestors, likely coincident with Plio-Pleistocene climatic oscillations between arid and humid conditions. According to a phylogeny derived from nuclear sequences, the Eurasian golden jackal (Canis aureus) diverged from the wolf/coyote lineage 1.9 million years ago, and with mitochondrial genome sequences indicating the Ethiopian wolf diverged from this lineage slightly prior to that. Further studies on RAD sequences found instances of Ethiopian wolves hybridizing with African golden wolves.

Subspecies

As of 2005, two subspecies are recognised by MSW3.

Physical description

The Ethiopian wolf is similar in size and build to North America's coyote; it is larger than the golden, black-backed, and side-striped jackals, and has relatively longer legs. Its skull is very flat, with a long facial region accounting for 58% of the skull's total length. The ears are broad, pointed, and directed forward. The teeth, particularly the premolars, are small and widely spaced. The canine teeth measure 14–22 mm in length, while the carnassials are relatively small. The Ethiopian wolf has eight mammae, of which only six are functional. The front paws have five toes, including a dewclaw, while the hind paws have four. As is typical in the genus Canis, males are larger than females, having 20% greater body mass. Adults measure 841–1,012 mm (33.1–39.8 in) in body length, and 530–620 mm (21–24 in) in height. Adult males weigh 14.2–19.3 kg (31–43 lb), while females weigh 11.2–14.15 kg (24.7–31.2 lb).

The Ethiopian wolf has short guard hairs and thick underfur, which provides protection at temperatures as low as −15 °C. Its overall colour is ochre to rusty red, with dense whitish to pale ginger underfur. The fur of the throat, chest and underparts is white, with a distinct white band occurring around the sides of the neck. There is a sharp boundary between the red coat and white marks. The ears are thickly furred on the edges, though naked on the inside. The naked borders of the lips, the gums and palate are black. The lips, a small spot on the cheeks and an ascending crescent below the eyes are white. The thickly furred tail is white underneath, and has a black tip, though, unlike most other canids, there is no dark patch marking the supracaudal gland. It moults during the wet season (August–October), and there is no evident seasonal variation in coat colour, though the contrast between the red coat and white markings increases with age and social rank. Females tend to have paler coats than males. During the breeding season, the female's coat turns yellow, becomes woolier, and the tail turns brownish, losing much of its hair.

Animals resulting from Ethiopian wolf-dog hybridisation tend to be more heavily built than pure wolves, and have shorter muzzles and different coat patterns.

Social and territorial behaviours

The Ethiopian wolf is a social animal, which lives in family groups containing up to 20 individuals older than one year, though packs of six wolves are more common. Packs are formed by dispersing males and a few females, which with the exception of the breeding female, are reproductively suppressed. Each pack has a well-established hierarchy, with dominance and subordination displays being common. Upon dying, a breeding female can be replaced by a resident daughter, though this increases the risk of inbreeding. Such a risk is sometimes circumvented by multiple paternity and extra-pack matings. The dispersal of wolves from their packs is largely restricted by the scarcity of unoccupied habitat.

These packs live in communal territories, which encompass 6 km² (2.3 sq mi) of land on average. In areas with little food, the species lives in pairs, sometimes accompanied by pups, and defends larger territories averaging 13.4 km² (5.2 sq mi). In the absence of disease, Ethiopian wolf territories are largely stable, but packs can expand whenever the opportunity arises, such as when another pack disappears. The size of each territory correlates with the abundance of rodents, the number of wolves in a pack, and the survival of pups. Ethiopian wolves rest together in the open at night, and congregate for greetings and border patrols at dawn, noon, and evening. They may shelter from rain under overhanging rocks and behind boulders. The species never sleeps in dens, and only uses them for nursing pups. When patrolling their territories, Ethiopian wolves regularly scent-mark, and interact aggressively and vocally with other packs. Such confrontations typically end with the retreat of the smaller group.

Reproduction and development

The mating season usually takes place between August and November. Courtship involves the breeding male following the female closely. The breeding female only accepts the advances of the breeding male, or males from other packs. The gestation period is 60–62 days, with pups being born between October and December. Pups are born toothless and with their eyes closed, and are covered in a charcoal-grey coat with a buff patch on the chest and abdomen. Litters consist of two to six pups, which emerge from their den after three weeks, when the dark coat is gradually replaced with the adult colouration. By the age of five weeks, the pups feed on a combination of milk and solid food, and become completely weaned off milk at the age of 10 weeks to six months. All members of the pack contribute to protecting and feeding the pups, with subordinate females sometimes assisting the dominant female by suckling them. Full growth and sexual maturity are attained at the age of two years.

Most females disperse from their natal pack at about two years of age, and some become "floaters" that may successfully immigrate into existing packs. Breeding pairs are most often unrelated to each other, suggesting that female-biased dispersal reduces inbreeding. Inbreeding is ordinarily avoided because it leads to a reduction in progeny fitness (inbreeding depression) due largely to the homozygous expression of deleterious recessive alleles.

Hunting behaviours

Unlike most social carnivores, the Ethiopian wolf tends to forage and feed on small prey alone. It is most active during the day, the time when rodents are themselves most active, though they have been observed to hunt in groups when targeting mountain nyala calves. Major Percy-Cotton described the hunting behaviour of Ethiopian wolves as thus:

... they are most amusing to watch, when hunting. The rats, which are brown, with short tails, live in big colonies and dart from burrow to burrow, while the cuberow stands motionless till one of them shows, when he makes a pounce for it. If he is unsuccessful, he seems to lose his temper, and starts digging violently; but this is only lost labour, as the ground is honeycombed with holes, and every rat is yards away before he has thrown up a pawful.

The technique described above is commonly used in hunting big-headed mole-rats, with the level of effort varying from scratching lightly at the hole to totally destroying a set of burrows, leaving metre-high earth mounds.

Wolves in Bale have been observed to forage among cattle herds, a tactic thought to aid in ambushing rodents out of their holes by using the cattle to hide their presence. Ethiopian wolves have also been observed forming temporary associations with troops of grazing geladas. Solitary wolves hunt for rodents in the midst of the monkeys, ignoring juvenile monkeys, though these are similar in size to some of their prey. The monkeys, in turn, tolerate and largely ignore the wolves, although they take flight if they observe feral dogs, which sometimes prey on them. Within the troops, the wolves enjoy much higher success in capturing rodents than usual, perhaps because the monkeys' activities flush out the rodents, or because the presence of numerous larger animals makes it harder for rodents to spot a threat.

Habitat

The Ethiopian wolf is restricted to isolated pockets of Afroalpine grasslands and heathlands inhabited by Afroalpine rodents. Its ideal habitat extends from above the tree line around 3,200 to 4,500 m, with some wolves inhabiting the Bale Mountains being present in montane grasslands at 3,000 m. Although specimens were collected in Gojjam and northwestern Shoa at 2,500 m in the early 20th century, no recent records exist of the species occurring below 3,000 m. In modern times, subsistence agriculture, which extends up to 3,700 m, has largely restricted the species to the highest peaks.

The Ethiopian wolf uses all Afroalpine habitats, but has a preference for open areas containing short herbaceous and grassland communities inhabited by rodents, which are most abundant along flat or gently sloping areas with poor drainage and deep soils. Prime wolf habitat in the Bale Mountains consists of short Alchemilla herbs and grasses, with low vegetation cover. Other favourable habitats consist of tussock grasslands, high-altitude scrubs rich in Helichrysum, and short grasslands growing in shallow soils. In its northern range, the wolf's habitat is composed of plant communities characterised by a matrix of Festuca tussocks, Euryops bushes, and giant lobelias, all of which are favoured by the wolf's rodent prey. Although marginal in importance, the ericaceous moorlands at 3,200-3,600 m in Simien may provide a refuge for wolves in highly disturbed areas.

Diet

In the Bale Mountains, the Ethiopian wolf's primary prey are big-headed mole-rats, though it also feeds on grass rats, black-clawed brush-furred rats, and highland hares. Other secondary prey species include vlei rats, yellow-spotted brush-furred rats, and occasionally goslings and eggs. Ethiopian wolves have twice been observed to feed on rock hyraxes and mountain nyala calves. In areas where the big-headed mole-rat is absent, the smaller East African mole-rat is targeted. In the Simien Mountains, the Ethiopian wolf preys on Abyssinian grass rats. Undigested sedge leaves have occasionally been found in Ethiopian wolf stomachs. The sedge possibly is ingested for roughage or for parasite control. The species may scavenge on carcasses, but is usually displaced by dogs and African golden wolves. It typically poses no threat to livestock, with farmers often leaving herds in wolf-inhabited areas unattended.

Range and populations

Six current Ethiopian wolf populations are known. North of the Rift Valley, the species occurs in the Simien Mountains in Gondar, in the northern and southern Wollo highlands, and in Guassa Menz in north Shoa. It has recently become extinct in Gosh Meda in north Shoa and Mount Guna, and has not been reported in Mount Choqa for several decades. Southeast of the