One region includes the southernmost tip of the continent, including South Africa, Namibia, Botswana, and Zimbabwe. The other area is along the eastern coastline, including Kenya, Somalia, Djibouti, Eritrea, and Ethiopia. It is listed by the IUCN as least concern, due to its widespread range and adaptability, although it is still persecuted as a livestock predator and rabies vector.[1]
Compared to other members of the genus Canis, the black-backed jackal is a very ancient species, and has changed little since the Pleistocene,[2] being the most basal wolf-like canine, alongside the closely related side-striped jackal.[3] It is a fox-like animal[4] with a reddish coat and a black saddle that extends from the shoulders to the base of the tail.[5] It is a monogamous animal, whose young may remain with the family to help raise new generations of pups.[6] The black-backed jackal is not a fussy eater, and feeds on small to medium-sized animals, as well as plant matter and human refuse.[7]
Etymology
The species is known by several different names, including saddle-backed, grey, silver-backed, red, and golden jackal (not to be confused with Canis aureus). The Latin mesomelas is a compound consisting of meso (middle) and melas (black).[5]Local and indigenous names
Taxonomy and evolution
| Phylogenetic tree of the extant wolf-like canids | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Phylogenetic relationships between the extant wolf-like clade of canids based on nuclear DNA sequence data taken from the cell nucleus,[3][8] except for the Himalayan wolf, based on mitochondrial DNA sequences.[8][9] Timing of divergence in millions of years.[8] |
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
Juliet Clutton-Brock classed the black-backed jackal as being closely related to the side-striped jackal, based on cranial and dental characters.[10] Studies on allozyme divergence within the Canidae indicate that the black-backed jackal and other members of the genus Canis are separated by a considerable degree of genetic distance.[11] Further studies show a large difference in mitochondrial DNA sequences between black-backed jackals and other sympatric "jackal" species, consistent with divergence 2.3–4.5 million years ago.[12]
A mitochondrial DNA (mDNA) sequence alignment for the wolf-like canids gave a phylogenetic tree with the side-striped jackal and the black-backed jackal being the most basal members of this clade, which means that this tree is indicating an African origin for the clade.[3][13]
Because of this deep divergence between the black-backed jackal and the rest of the "wolf-like" canids, one author has proposed to change the species' generic name from Canis to Lupulella.[14]
The golden jackal was once thought to occupy Africa and Eurasia. In 2015, a genetic study found that the golden jackal of Africa was a separate species to that of Eurasia, and so it was renamed the African golden wolf. In 2017, jackal relationships were further explored, with an mDNA study finding that the two black-backed jackal subspecies had diverged from each other 1.4 million years ago to form the central African and east African populations. The study proposes that due to this long separation, which is longer than the separation of the African golden wolf from the wolf lineage, that the two subspecies might warrant separate species status.[15]
- See further:Canis evolution
Subspecies
Two subspecies are recognised by MSW3[16] (2005). These subspecies are geographically separated by a gap which extends northwards from Zambia to Tanzania:[5]| Subspecies | Image | Trinomial authority | Description | Range | Synonyms |
|---|---|---|---|---|---|
| Cape jackal C. m. mesomelas nominate subspecies |
.jpg)
|
Schreber, 1775 | See Physical description below. | Cape of Good Hope northward to Angola, Namibia, Zimbabwe, and southern Mozambique. | achrotes (Thomas, 1925) arenarum (Thomas, 1926) variegatoides (A. Smith, 1833) |
| East African jackal C. m. schmidti |
|
Noack, 1897 | Distinguished from the nominate subspecies by its shorter and wider skull, longer and narrower carnassials, and smaller upper and lower molar grinding areas. | Southern Ethiopia, South Sudan, Somalia, Kenya, Uganda, and northern Tanzania. | elgonae (Heller, 1914) mcmillani (Heller, 1914) |
Description
The base colour is reddish brown to tan, which is particularly pronounced on the flanks and legs. A black saddle intermixed with silvery hair extends from the shoulders to the base of the tail.[5] A long, black stripe extending along the flanks separates the saddle from the rest of the body, and can be used to differentiate individuals.[4] The tail is bushy and tipped with black. The lips, throat, chest, and inner surface of the limbs are white.[5] The winter coat is a much deeper reddish brown.[4] Albino specimens occasionally occur.[4] The hair of the face measures 10–15 mm in length, and lengthens to 30–40 mm on the rump. The guard hairs of the back are 60 mm on the shoulder, decreasing to 40 mm at the base of the tail. The hairs of the tail are the longest, measuring 70 mm in length.[7]
Behaviour
East African jackal (C. m. schmidti) pups, Tanzania
Social and territorial behaviours
The black-backed jackal is a monogamous and territorial animal, whose social organisation greatly resembles that of the golden jackal. However, the assistance of elder offspring in helping raise the pups of their parents has a greater bearing on pup survival rates than in the latter species.[6] The basic social unit is a monogamous mated pair which defends its territory through laying faeces and urine on range boundaries. Scent marking is usually done in tandem, and the pair aggressively expels intruders. Such encounters are normally prevented, as the pair vocalises to advertise its presence in a given area. It is a highly vocal species, particularly in Southern Africa.[4] Sounds made by the species include yelling, yelping, woofing, whining, growling, and cackling.[6] It communicates with group members and advertises its presence by a high-pitched, whining howl, and expresses alarm through an explosive cry followed by shorter, high-pitched yelps. This sound is particularly frantic when mobbing a leopard. In areas where the black-backed jackal is sympatric with the African golden wolf, the species does not howl, instead relying more on yelps. In contrast, black-backed jackals in Southern Africa howl much like golden jackals.[4] When trapped, it cackles like a fox.[6]Reproduction and development
The mating season takes place from late May to August, with a gestation period of 60 days. Pups are born from July to October. Summer births are thought to be timed to coincide with population peaks of vlei rats and four-striped grass mice, while winter births are timed for ungulate calving seasons.[7] Litters consist of one to 9 pups, which are born blind. For the first three weeks of their lives, the pups are kept under constant surveillance by their dam, while the sire and elder offspring provide food.[6] The pups open their eyes after 8–10 days and emerge from the den at the age of 3 weeks. They are weaned at 8–9 weeks, and can hunt by themselves at the age of 6 months. Sexual maturity is attained at 11 months, though few black-backed jackals reproduce in their first year.[4] Unlike golden jackals, which have comparatively amicable intrapack relationships, black-backed jackal pups become increasingly quarrelsome as they age, and establish more rigid dominance hierarchies. Dominant pups appropriate food, and become independent at an earlier age.[6] The grown pups may disperse at one year of age, though some remain in their natal territories to assist their parents in raising the next generation of pups. The average lifespan in the wild is 7 years, though captive specimens can live twice as long.[4]Ecology
Habitat
The species generally shows a preference for open areas with little dense vegetation, though it occupies a wide range of habitats, from arid coastal deserts to areas with more than 2000 mm of rainfall. It also occurs in farmlands, savannas, open savanna mosaics, and alpine areas.[4]Diet
.jpg)
Cape jackal (C. m. mesomelas) feeding on a brown fur seal pup, Namibia
Cape jackal (C. m. mesomelas) feeding on a springbok carcass in Etosha National Park, Namibia
Enemies and competitors
In areas where the black-backed jackal is sympatric with the larger side-striped jackal, the former species aggressively drives out the latter from grassland habitats into woodlands. This is unique among carnivores, as larger species commonly displace smaller ones.[20] Black-backed jackal pups are vulnerable to African golden wolves,[7] ratels, and spotted and brown hyenas. Adults have few natural predators, save for leopards, caracals, African wild dogs, and martial eagles.[4]Diseases and parasites
Black-backed jackals can carry diseases such as rabies, canine parvovirus, canine distemper, canine adenovirus, Ehrlichia canis, and African horse sickness. Jackals in Etosha National Park may carry anthrax. Black-backed jackals are major rabies vectors, and have been associated with epidemics, which appear to cycle every 4–8 years. Jackals in Zimbabwe are able to maintain rabies independently of other species. Although oral vaccinations are effective in jackals, the long-term control of rabies continues to be a problem in areas where stray dogs are not given the same immunisation.[5]Jackals may also carry trematodes such as Athesmia, cestodes such as Dipylidium caninum, Echinococcus granulosus, Joyeuxialla echinorhyncoides, J. pasqualei, Mesocestoides lineatus, Taenia erythraea, T. hydatigena, T. jackhalsi, T. multiceps, T. pungutchui, and T. serialis. Nematodes carried by black-backed jackals include Ancylostoma braziliense, A. caninum, A. martinaglia, A. somaliense, A. tubaeforme, and Physaloptera praeputialis, and protozoans such as Babesia canis, Ehrlichia canis, Hepatozoon canis, Rickettsia canis, Sarcocytis spp., Toxoplasma gondii, and Trypanosoma congolense. Mites may cause sarcoptic mange. Tick species include Amblyomma hebraeum, A. marmoreum, A. nymphs, A. variegatum, Boophilus decoloratus, Haemaphysalis leachii, H. silacea, H. spinulosa, Hyelomma spp., Ixodes pilosus, I. rubicundus, Rhipicephalus appendiculatus, R. evertsi, R. sanguineus, and R. simus. Flea species include Ctenocephalides cornatus, Echidnophaga gallinacea, and Synosternus caffer.[5]
Relationships with humans
In folklore
Black-backed jackals feature prominently in the folklore of the Khoikhoi, where it is often paired with the lion, whom it frequently outsmarts or betrays with its superior intelligence. One story explains that the black-backed jackal gained its dark saddle when it offered to carry the Sun on its back.[21] An alternative account comes from the ǃKung people, whose folklore tells that the jackal received the burn on its back as a punishment for its scavenging habits.[22] According to an ancient Ethiopian folktale, jackals and man first became enemies shortly before the Great Flood, when Noah initially refused to allow jackals into the ark, thinking they were unworthy of being saved, until being commanded by God to do so.[23]Livestock predation
Black-backed jackals occasionally hunt domestic animals, including dogs, cats, pigs, goats, sheep, and poultry, with sheep tending to predominate. They rarely target cattle, though cows giving birth may be attacked. Jackals can be a serious problem for sheep farmers, particularly during the lambing season. Sheep losses to black-backed jackals in a 440 km2 study area in KwaZulu-Natal consisted of 0.05% of the sheep population. Of 395 sheep killed in a sheep farming area in KwaZulu-Natal, 13% were killed by jackals. Jackals usually kill sheep with a throat bite, and begin feeding by opening the flank and consuming the flesh and skin of the flank, heart, liver, some ribs, haunch of hind leg, and sometimes the stomach and its contents. In older lambs, the main portions eaten are usually heart and liver. Usually, only one lamb per night is killed in any one place, but sometimes two and occasionally three may be killed.[5] The oral history of the Khoikhoi indicates they have been a nuisance to pastoralists long before European settlement. South Africa has been using fencing systems to protect sheep from jackals since the 1890s, though such measures have mixed success, as the best fencing is expensive, and jackals can easily infiltrate cheap wire fences.[24]Hunting
Black-backed jackal pelt
Spring traps with metal jaws were also effective, though poisoning by strychnine became more common by the late 19th century. Strychnine poisoning was initially problematic, as the solution had a bitter taste, and could only work if swallowed. Consequently, many jackals learned to regurgitate poisoned baits, thus inciting wildlife managers to use the less detectable crystal strychnine rather than liquid. The poison was usually placed within sheep carcasses or in balls of fat, with great care being taken to avoid leaving any human scent on them. Black-backed jackals were not a popular quarry in the 19th century, and are rarely mentioned in hunter's literature. By the turn of the century, jackals became increasingly popular quarry as they encroached upon human habitations after sheep farming and veld burning diminished their natural food sources. Although poisoning had been effective in the late 19th century, its success rate in eliminating jackals waned in the 20th century, as jackals seemed to be learning to distinguish poisoned foods.[24]
The Tswana people often made hats and cloaks out of black-backed jackal skins. Between 1914 and 1917, 282,134 jackal pelts (nearly 50,000 a year) were produced in South Africa. Demand for pelts grew during the First World War, and were primarily sold in Cape Town and Port Elizabeth. Jackals in their winter fur were in great demand, though animals killed by poison were less valued, as their fur would shed.[24]
Black-backed jackal range, with C. m. mesomelas in blue and C. m. schmidti in red
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.