Black-backed jackal
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Black-backed jackal ( Canis mesomelas ) |
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| Canis mesomelas | ||||||||||||
| Schreber , 1775 |
The black-backed jackal ( Canis mesomelas ) is a wild dog of the African savannah and is counted among the real dogs of the genus Canis . With an average body length of 75 centimeters and a shoulder height of less than 50 centimeters, it belongs to the smaller species within the genus. Compared to other jackals , the characteristic and name-giving feature is a dark saddle mark that extends over the back.
The range of the black-backed jackal covers two approximately 1,000 kilometers separated areas in Africa. One includes Tanzania , Kenya , Somalia and Ethiopia in East Africa, the other is in southern Africa in South Africa , Namibia , Botswana and Zimbabwe . They live in family groups and are mostly nocturnal. Black-backed jackals feed on a wide range of carnal foods, ranging from insects to larger mammals and carrion. They are very adaptable and also live near human habitation. Due to their size, they are not classified as endangered and in many areas they are hunted as a threat to the livestock industry and as a carrier of rabies .
features
general characteristics
The black-backed jackal is one of the smaller species within the genus Canis with a fox-like exterior. He is very slender with long legs and big ears. The males are slightly larger and heavier than the females. The head-torso length of the males is 71 to 81 centimeters, on average about 75 centimeters, and that of the females 64 to 73 centimeters, on average 69 centimeters; the shoulder height is 38 to 48 centimeters for both. The tail reaches an average length of 32 centimeters for the males and 30 centimeters for the females. The average weight of the males is 8.4 kilograms (6.4 to 11.4) and the females 7.7 (5.9 to 10.0). The head corresponds to that of a dog with a pointed muzzle and upright, pointed and triangular ears.
The basic color of the jackals is red-brown. The black-backed jackal is clearly characterized by the slate-gray back spot with silver-gray hair from the neck to the tail, which contrasts with the rust-red to golden-yellow fur of the head, the flanks, the underside and the legs; the legs and the flanks are much more red in color than the rest of the body. The back spot is widest in the area of the shoulders, becomes narrower towards the tail and tapers in the area of the pelvis. This Sattelfleck is eponymous for the animal because animals with a corresponding drawing as valances are called. The also red-brown, bushy tail ends in a black tip, while the closely related striped jackal has a white tip. The lips and fur on the chin, throat and the inside of the legs are white. The length of the fur is around 60 millimeters at the shoulders and around 40 millimeters at the base of the tail, and up to 90 millimeters long at the tip of the tail. On the face, the hair reaches a length of 10 to 15 millimeters.
The young animals are colored lead gray, the saddle spot is only indistinctly developed; they reach their characteristic fur color after about six months. Albinism can occur but is very rare.
Features of the skull
The skull of the black-backed jackal is elongated and has a pear-shaped skull and a very narrow snout region. A sagittal ridge is only formed in the rear area of the skull, in the front area it divides into two flat ridges that end behind the eyebrows. The size of the skull corresponds to that of other jackals with an average total length of 150 millimeters (138.9 to 160.5) in the male and 145.6 millimeters (135.2 to 157.1) in the female. In the area of the zygomatic arches , the skull has a width of 85.9 millimeters (78.7 to 94.3) in the male and 83.3 (77.2 to 90.3) in the female. The skulls of the animals in the East African distribution area are slightly shorter and wider than those in South Africa and have less variability.
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The dentition corresponds to the typical dog bite with three incisors , one canine , four premolar and two molars in the upper jaw as well as the same number of teeth and an additional molar in the lower jaw.
The length of the penis bone (baculum) corresponds to the total length of the penis and is I-shaped. The groove for the urethra is formed from the tip of the penis to about three quarters of the length of the bone. The typical length of the penis bone in a one to five year old black-backed jackal is 56.8 millimeters with an average weight of 299 milligrams.
genetics
The black-backed jackal has a simple chromosome set (s) of 39 and a diploid chromosome set of 2n = 78, so it has a total of 78 chromosomes in each cell. With the exception of a very large and a very small submetacentric pair, all chromosomes are acrocentric .
distribution and habitat
Distribution area
The range of the black-backed jackal covers two approximately 1,000 kilometers separated areas in Africa. One includes Tanzania , Kenya , Somalia , Uganda, South Sudan, Eritrea, Burundi and Ethiopia in East Africa, the other is in South Africa in South Africa , Lesotho, Eswatini, Namibia , Angola, Botswana , Zimbabwe , Zambia and Mozambique. The species, however, is absent in most of central and equatorial Africa.
This distribution pattern corresponds to that of other mammals adapted to dry regions such as the aardwolf ( Proteles cristatus ) and the spoonhound ( Otocyon megalotis ). The distribution pattern suggests that these two areas were originally linked by similar habitats between southwest Africa and the Horn of Africa .
habitat
The preferred habitat of these species are steppes and semi-deserts and the black-backed jackal can survive even in extremely dry areas. He uses different habitats , including coastal dry areas, montane grassland, dry savannas, bushland, open savannah areas, loose forest areas and cultivated areas. They prefer open landscapes and avoid dense vegetation. The altitude distribution in KwaZulu-Natal ranges from sea level to 3,000 meters in the Drakensberg with more than 2,000 millimeters of rainfall per year.
In areas in which besides the black-backed jackal other species such as the striped jackal ( Canis adustus ) or the African golden wolf ( Canis anthus ) occur, the existing habitats are divided between the species. The black-backed jackal prefers to use open grassland when it occurs sympathetically with the striped jackal, or wooded savannahs when it lives sympathetically with the golden and striped jackal. Aggressive clashes broke out in western Zimbabwe, with the black-backed jackal displacing the striped jackal from the grasslands.
Way of life
Black-backed jackals live in family groups. The daily activity time of the jackals is between 20 and 48% of the day and increases at the time of rearing young. They are mainly nocturnal, with the main activity times occurring after sunset or before sunrise and thus very much coinciding with the activity times of the prey animals. Activity is lowest during the full moon and new moon phases, and increases on nights with moderate moon lighting. Especially in areas where they are undisturbed, they can also have activity times during the day; In regions where they are strongly disturbed by humans, however, they are strictly nocturnal.
Black-backed jackals form family groups of eight to ten, sometimes significantly more, for hunting and foraging. The jackal pair and the offspring represent the core of a group that other animals can join. In addition to the pair, there are usually young animals from the last litter in the group, helpers who do not intend to mate, and solitary and non-territorial individual animals.
nutrition
As a predator, the black-backed jackal feeds primarily on meat. The diet is not very specialized and depends very much on the availability of various prey and other food sources. The food spectrum mainly includes small and medium-sized mammals, reptiles, birds and bird eggs, invertebrates such as beetles and grasshoppers, as well as carrion and food residues in the garbage from human dwellings, as well as plant foods such as peanuts , berries and grapes.
Jackals are capable of striking an adult springbok ( Antidorcas marsupialis ) and other large ungulates. In South Africa hoofed animals make like the springbok and other antelope as the Impala ( Aepyceros melampus ) next to Duiker ( Sylvicapra grimmia ), the southern reedbuck ( Redunca arundinum ) and the steenbok ( Raphicerus campestris ) a substantial portion of the food is There are also juveniles of. Zebras or wildebeest ( Connochaetes taurinus ), and there are indications that the jackals and the nests African ostriches ( Struthio camelus ) plunder. The hunt takes place in the family group or in loose association with other groups if enough food is available. The chances of hunting a Thomson's gazelle ( Eudorcas thomsoni ), for example, increase to around 67% if two jackals are involved, compared to 16% for a lone hunter. With a fawn , on the other hand, the chances of hunting are no different and are around 75% for both couples and individuals. When hunting, the animals run towards the prey and increase their speed to a fast gallop. If they can reach the prey, they bite into a leg, flank, neck or muzzle and bring the prey down; killing occurs by biting the throat or, less often, by tearing open the abdominal cavity.
His extreme adaptability allowed him to develop a large number of regionally different behavior patterns. In East Africa, these jackals (like the African gold wolves ) follow the pride of lions and wait for them to let go of their prey and then eat the rest of the carcass. They also hunt together with cheetahs ( Acinonyx jubatus ). Large groups of jackals sometimes specialize in waiting for gazelles to be born in order to kill the young immediately after birth. In addition to various rodents and rabbits, the jackals also prey on smaller predators such as martens and crawling cats as well as domestic dogs and domestic cats . In southern Africa, especially in Namibia , some black-backed jackals have made the coast their habitat. Here they live near the Seebärkolonien and feed on sea birds, seals boys and placentas (z. B. at the Skeleton Coast ) and washed up shells and fish. Up to 80 jackals have been counted on beaches with fur seal colonies. In southern Africa some black-backed jackals became cultural successors . They settled near human villages and cities, where they empty garbage cans, but also tear lambs and young goats, especially during the littering season. The domestic animals are not the main prey of the jackals, as could be shown in a study in KwaZulu-Natal : Here the losses by the black-backed jackal amounted to about 0.05% of the sheep population and the attacks took place mainly in the dry season during the whelping season Sheep. In the same area, of 395 sheep killed by black-backed jackals and 83% by stray domestic dogs were killed.
The black-backed jackal competes primarily with the aardwolf ( Proteles cristatus ), the spoonbill ( Otocyon megalotis ), the Cape fox ( Vulpes chama ), the spotted hyena ( Crocuta crocuta ) as well as the striped jackal and the African gold wolf. In some areas, such as the Namib , the various predators are accordingly nodding in due to different food preferences, spatial distribution and activity time, so that several species can occur sympatric . Especially in the areas in which the three jackal species occur, there is a distribution of habitats that avoids competition. Compared to the Cape fox and the spoonbill fox, the black-backed jackal is dominant and it also hunts and kills these smaller species. In the regions where the smaller foxes are found together with the black-backed jackal, this has clear effects on the density of individuals, which increases by up to 64% in the Cape fox when they are absent, and the activity space, which is significantly greater when the jackals are absent. In addition, the activity of the Cape foxes increases in daylight and the bucket dogs form smaller groups when no jackals are present. The mutual nesting of both species is also influenced by the black-backed jackals.
Reproduction and development
The black-backed jackal is monogamous . It reaches sexual maturity at around 11 months, but in the wild, females only get young from around two years of age.
The gestation period is 60 to 65 days. The times of birth vary greatly from region to region and depend on both the habitat and the availability of food. In the Rift Valley in Kenya, females give birth between September and January, while in northern Tanzania and Kwa-Zulu Natal they give birth between June and September and in South Africa between August and October.
The births take place in underground structures and the size of the litters is one to nine young animals, usually three to six. These are born blind and open their eyes after eight to ten days. The teeth of the deciduous dentition erupt completely within the first three weeks and after about three weeks the young animals start eating pre-chewed food. After eight to ten weeks, they are weaned. The juveniles leave the den for the first time after about three weeks, but remain underground for most of the first seven weeks. After around 12 to 14 weeks they leave the burrows and start hunting with their parents. The permanent molars erupt after 14 to 23 weeks and the entire deciduous teeth are replaced by permanent teeth in the first year of life.
The mortality among young animals is highest in the first 14 weeks; usually only one to three young animals survive this time in a litter. In the Serengeti in Tanzania, about 24% of the young animals stay with their parents in the family for the first one and a half to two years after weaning, the rest dissipate after about ten to eleven months. The maximum age in the wild is about twelve years, whereby the animals usually do not grow older than seven years.
Predators and parasites
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The young black-backed jackals can potentially be preyed on by any large enough predator in the animal's habitat. Both spotted hyenas and striped jackals have been observed killing young black-backed jackals. Their main threat, however, are birds of prey; the martial eagle ( Polemaetus bellicosus ) was seen capturing a subadult jackal and carrying it away. For the adult animals, the main enemy next to humans is the leopard (Panthera pardus). In field studies, a leopard was observed that captured eleven black-backed jackals over a period of three weeks. In some regions, the jackals are likely one of the leopards' main prey animals.
Numerous parasites can attack the black-backed jackal. Among the most important internal parasites include various tapeworms as Dipylidium caninum , Echinococcus granulosus , Joyeuxialla echinorhyncoides , Joyeuxialla pasqualei , Mesocestoides lineatus , Taenia erythraea , Taenia hydatigena , Taenia jackhalsi , Taenia mulitceps , Taenia pungutchui and Taenia serialis , trematodes of the genus Athesmia and nematodes such as Ancylostoma braziliense , Ancylostoma caninum , Ancylostoma martinaglia , Ancylostoma somaliense , Ancylostoma tubaeforme and Physaloptera praeputialis . Various unicellular parasites can attack the black-backed jackal, especially Babesia canis , Ehrlichia canis , Hepatozoon canis , Rickettsia canis , Sarcocytis , Toxoplasma gondii and Trypanosoma congolense . Ectoparasites are primarily ticks and other mites, as well as several types of fleas .
In addition to these parasites, black-backed jackals can also be infected by viruses such as rabies virus (the causative agent of rabies ), canine parvovirus , distemper virus , canine adenovirus and the causative agent of canine erlichiosis , and the anthrax pathogen Bacillus anthracis has also been detected in black-backed jackal. Black- backed jackals are particularly important vectors for rabies and there are several rabies epidemics that can be traced back to infected jackals. Rabies occurs in jackals periodically in cycles of four to eight years, which are mainly explained by periods of rain and the associated social behavior of the animals. Rabies control is carried out by feeding them vaccines, but long-term and permanent control of the disease also depends on the vaccination of domestic dogs in the area of distribution.
Evolution and systematics
Fossil history
Fossils of the black-backed jackal from South Africa document the species up to the Pleistocene around two to three million years ago in Kenya, Tanzania and South Africa, but were never found further north than Ethiopia . The species was therefore always restricted to the areas south of the Sahara . The fossil individuals were described as Canis antiquus and were about the same size as today's, recent representatives of the species, they differ from these only in small differences in the relative size of the bones of the nasal region and can be assigned to the recent black-backed jackal.
Systematics
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Phylogenetic system of the genus Canis according to Koepfli et al. 2015
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The black-backed jackal is assigned to the genus of the wolf-like and jackal-like ( Canis ), which comprises a total of eight species. In addition to other species known as jackals, it mainly includes dogs of the wolf type . The first scientific description was made in 1775 by the German naturalist Johann Christian von Schreber on the basis of an individual from South Africa. He referred to the species directly as Canis mesomelas and classified it accordingly in the genus Canis . The species name “mesomelas” derives from the words “meso” for “middle” and “melas” for “black” and refers to the black drawing on the back.
Later descriptions of other localities by different scientists were later summarized and synonymous with this species . These are the following synonyms:
- Canis variegatoides Smith, 1833,
- Canis schmidtii Noack, 1897,
- Canis mcmillani Heller, 1914,
- Canis elgonae Heller, 1914,
- Canis arenarum Thomas, 1926 and
- Canis Achrotes Thomas, 1926.
In 1906 Hilzheimer's species was transferred to his own genus Lupulella as Lupulella mesomelas , but this was not scientifically recognized.
As part of the presentation of the genome sequence of the domestic dog , Lindblad-Toh et al. 2005 published a phylogenetic analysis of dogs (Canidae). In the context of this presentation, the monophyly of the genus Canis was questioned on the basis of molecular biological data . Accordingly, the strip and the Schakal jackal provide sister species , which fall as basalste types of all other members of the genus, and in addition the Rothund ( Cuon alpinus ) and the African wild dog ( Lycaon pictus ) are compared. These two species would have to be included in the Canis genus in order for it to survive as a monophyletic genus. Zrzavý and Řičánková also came to this conclusion in 2004 and suggested separating the two jackals from the genus Canis ; Following their proposal, the striped jackal of the monotypical genus Schaeffia should be classified as Schaeffia adusta and the black-backed jackal of the genus Lupulella as Lupulella mesomelas . The Canid Specialist Group of the IUCN spoke out at a congress held in May 2019 in favor of placing both the black-backed jackal and the barred jackal in the genus Lupulella .
Within the species two subspecies are distinguished, which coincide with the two large distribution areas. The southern subspecies C. m. mesomelas is accordingly restricted to the southern distribution area, while C. m. schmidtii occurs in East Africa. The two subspecies differ mainly in the size of the skull: The skull of the East African subspecies is shorter and wider, and its dimensions are less variable. It also has longer and narrower fangs and smaller chewing surfaces.
Inventory and status
The species is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as not endangered (least concern) due to the size of the population. The black-backed jackal is relatively common within its range and is characterized by an opportunistic way of life.
The black-backed jackal is hunted in many areas as a threat to the livestock industry and as a carrier of rabies , but this population control is only effective locally. Hunting with traps to obtain fur is less common. In addition, in areas with high human densities, accidents with cars occur regularly. Hunting can lead to greater populations or even to complete extinction of the populations.
supporting documents
- ↑ a b c d e f g h i j k l m n o p q r s t u v w Lyle R. Walton, Damien O. Joly: Canis mesomelas . In: Mammalian Species . tape 715 , 2003, p. 1–9 ( full text (PDF; 728 kB)).
- ↑ a b c d e f g Canis mesomelas in the Red List of Threatened Species of the IUCN 2011.2. Listed by: AJ Loveridge, JAJ Nel, 2008. Retrieved May 20, 2012.
- ^ A b Claudio Sillero-Zubiri: Family Canidae (Dogs). (352-447). In: Wilson, DE, Mittermeier, RA (Eds.). Handbook of the Mammals of the World. Volume 1: Carnivores. Lynx Edicions, 2009; Pp. 419-420. ISBN 978-84-96553-49-1 .
- ↑ Jan F. Kamler, Ute Stenkewitz, David W. Macdonald: Lethal and sublethal effects of black-backed jackals on cape foxes and bat-eared foxes. Journal of Mammalogy 94 (2), 2013; Pp. 295-306. ( Abstract )
- ↑ a b c d e Claudio Sillero-Zubiri, Michael Hoffmann, David W. Macdonald (IUCN / SSC Canid Specialist Group): Canids: Foxes, Wolves, Jackals and Dogs Status Survey and Conservation Action Plan. IUCN - The World Conservation Union, 2004, pp. 161–166 ( full text, PDF ( memento of October 6, 2011 in the Internet Archive ))
- ↑ Klaus-Peter Koepfli, John Pollinger, Raquel Godinho, Jacqueline Robinson, Amanda Lea, Sarah Hendricks, Rena M. Schweizer, Olaf Thalmann, Pedro Silva, Zhenxin Fan, Andrey A. Yurchenko, Pavel Dobrynin, Alexey Makunin, James A. Cahill , Beth Shapiro, Francisco Álvares, José C. Brito, Eli Geffen, Jennifer A. Leonard, Kristofer M. Helgen, Warren E. Johnson, Stephen J. O'Brien, Blaire Van Valkenburgh, Robert K. Wayne: Genome-wide Evidence Reveals that African and Eurasian Golden Jackals Are Distinct Species. In: Current Biology. 2015, doi : 10.1016 / j.cub.2015.06.060 .
- ↑ Kerstin Lindblad-Toh et al .: Genome sequence, comparative analysis and haplotype structure of the domestic dog. Nature 438, December 2005; Page 803–819. ( Abstract ).
- ↑ Jan Zrzavý, Věra Řičánková: Phylogeny of Recent Canidae (Mammalia, Carnivora): Relative Reliability and Utility of Morphological and Molecular Datasets. In: Zoologica Scripta Volume 33, No. 4, July 2004, pp. 311-333, doi : 10.1111 / j.0300-3256.2004.00152.x .
- ↑ Francisco Alvares, Wieslaw Bogdanowicz, Liz AD Campbell, Raquel Godinho, Jennifer Hatlauf, Yadvendradev V. Jhala, Andrew C. Kitchener, Klaus-Peter Koepfli, Miha Krofel, Helen Senn, Claudio Sillero-Zubiri, Suvi Viranta and Geraldine Werhahn: Old World Canis spp. with taxonomic ambiguity : Workshop conclusions and recommendations. Vairão, Portugal, 28th-30thMay 2019, IUCN / SSC Canid Specialist Group, PDF
- ↑ Don E. Wilson & DeeAnn M. Reeder (eds.): Canis mesomelas in Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed).
literature
- Lyle R. Walton, Damien O. Joly: Canis mesomelas . In: Mammalian Species . tape 715 , 2003, p. 1–9 ( PDF, 728 kB ).
- Claudio Sillero-Zubiri: Family Canidae (Dogs). In: DE Wilson and RA Mittermeier (eds.): Handbook of the Mammals of the World. Volume 1: Carnivores. Lynx Edicions, 2009, ISBN 978-84-96553-49-1 , pp. 352-447, here: pp. 419-420.
- Claudio Sillero-Zubiri, Michael Hoffmann, David W. Macdonald (IUCN / SSC Canid Specialist Group): Canids: Foxes, Wolves, Jackals and Dogs Status Survey and Conservation Action Plan. IUCN - The World Conservation Union, 2004, pp. 161–166 ( PDF ( Memento of October 6, 2011 in the Internet Archive )).
Web links
- Canis mesomelas inthe IUCN 2011 Red List of Threatened Species . Listed by: AJ Loveridge, JAJ Nel, 2008. Retrieved May 20, 2012.
