A black wolf is a melanistic colour variant of the gray wolf (Canis lupus). [1] [2] Black specimens were recorded among red wolves (Canis rufus), though the colour phase in this species is not extinct yet. [3] Genetic research from the Stanford University School of Medicine and the University of California, Los Angeles revealed that wolves with black pelts owe their distinctive coloration to a mutation which occurred in domestic dogs, and was carried to wolves through wolf-dog hybridization. [1] Besides coat and knee colour, they are normal grey wolves.
Linnaeus gave the black wolves of Europe the binomial name Canis lycaon, under the assumption that the species was distinct from grey- and white-coloured wolves. Cuvier and other naturalists largely followed his example. [4] Black wolves were considered rare in France, but common in Southern Europe at the time, with black wolf populations south to the Pyrenees apparently outnumbering other colour phases. They also occurred in the mountains of Friuli (Italy) and around Kotor (Montenegro). Black wolves were also reported in Siberia as the Vekvoturian Mountain-wolf. [5] Colonel Smith erroneously believed that the so-called "Rossomak" of the Lenas in Siberia was of the same variety. [6] However, in fact, "Rossomak" in Russian exactly corresponds with the English "wolverine", a mustelid species, in English (Gulo gulo in Latin). Black wolves were considered rare in northern Europe; however, Dr. Höggberg, a medical practitioner at Karlstad mentioned five black wolves being killed in the Swedish province of Värmland in 1801. These wolves were completely black and were bigger than the more common grey variety. Their pelts were considered exotic enough to be sold for three to four times the price established for more common colour phases. [7] Also, the last wolf in Scotland, supposedly killed by MacQueen of Pall à Chrocain, is usually narrated as having been black. [8] Cuvier noted that European black wolves differed little in size from other colour phases, but exceeded them in physical strength. [6] Charles Hamilton Smith wrote that black wolves were generally less aggressive than ordinary kinds, and interbred with dogs more readily. [5] In Serbia (Southeastern Europe, the Balkan Peninsula) indicated that on 17 November 2012, a black wolf was killed at Stara Mountain. [9] [10]
Black wolves were occasionally reported in Asia. The "Derboun" of the Arabian mountains and southern Syria was a small black wolf which apparently was considered by the Arabs to be more closely related to dogs, as they freely ate its flesh like any other game, unlike with regular wolves which had an unpleasant odour. [5] Black wolves in Tibet are known locally as chanko nagpo, and are considered bolder and more aggressive than the pale-coloured variety. Small populations inhabit Ladakh. [11]
Although the black wolves of America were originally given the same binomial name as those in Europe, Anselme Gaëtan Desmarest believed that they were a different species. [12] Historically, the natives of the banks of the Mackenzie River, Saskatchewan River and southern Canada apparently never viewed black wolves as a distinct species. [13] In his 1791 book Travels, William Bartram mentioned seeing black wolves among the few red wolf populations he saw in Florida. He stated that they were "perfectly black", except the females which were described as having a white spot on the breast. Bartram also described a "black wolf-dog of the Florida Indians" which was identical to the local wolves, save for the fact that it could bark, and could be trusted around horses. [5] The fur of a black wolf was once considered by the natives of New England to be worth over 40 beaver skins. A chieftain accepting a gift of black wolf fur was seen as an act of reconciliation. [14] The black wolves of the Southern United States were considered a separate species to the northern kind due to differences in colour and morphology, and were named dusky or clouded wolves (Canis nubilus). [4] [15] The dusky wolves occurred in the Missouri Territory, and were intermediate in size between common wolves and coyotes. They apparently produced a foul odour. [16] On January 15, 2009, a male black wolf from "Mollie's Pack" in the Yellowstone National Park's Pelican Valley was weighed in at 143 lbs, making it the largest Yellowstone wolf on record. [17]
Adolph Murie was among the first wolf biologists to speculate that the wide color variation in wolves was due to interbreeding with dogs; [18]
I suppose that some of the variability exhibited in these wolves could have resulted from crossings in the wild with dogs. Such crosses in the wild have been reported and the wolf in captivity crosses readily with dogs. Some years ago at Circle, Alaska, a wolf hung around the settlement for some time and some of the dogs were seen with it. The people thought that the wolf was a female attracted to the dogs during the breeding period. However, considerable variability is probably inherent in the species, enough perhaps to account for the variations noted in the park and in skins examined. The amount of crossing with dogs has probably not been sufficient to alter much the genetic composition of the wolf population.
— The Wolves of Mount McKinley by Adolph Murie, 1944, ISBN 0-295-96203-8, 978-0-295-96203-0, 238 pages
In 2008, Dr. Gregory S. Barsh, a professor of genetics and pediatrics at the Stanford University School of Medicine used molecular genetic techniques to analyze DNA sequences from 150 wolves, half of them black, in Yellowstone National Park, which covers parts of Wyoming, Montana and Idaho. It was discovered that a gene mutation responsible for the protein beta-defensin 3, known as the K locus, is responsible for the black coat colour in dogs. [19] After finding that the same mutation was responsible for black wolves in North America and the Italian Apennines, he set out to discover the origin of the mutation. Dr. Barsh and his colleagues concluded that the mutation arose in dogs 12,779 to 121,182 years ago, with a preferred date of 46,886 years ago after comparing large sections of wolf, dog and coyote genomes. [1] At the University of California, Los Angeles, Robert K. Wayne, a canine evolutionary biologist, stated that he believed that dogs were the first to have the mutation. He further stated that, even if it originally arose in Eurasian wolves, it was passed on to dogs who, soon after their arrival, brought it to the New World and then passed it on to wolves and coyotes. [20] Black wolves with recent dog ancestry tend to retain black pigment longer as they age. [21] This beta-defensin K locus mutation is a dominant black mutation that occurs in many domestic dog breeds. [22] [23]
However, a recessive black gene also occurs in a few domestic dog breeds (notably in all-black German Shepherds, but also in some black Border Collies, Australian Shepherds, and Belgian Shepherds). [24] This recessive allele is a recessive allele in the Agouti gene in dogs (R96C arginine to cysteine mutation at codon 96). [24] This recessive black gene is also thought to have derived from wild Eurasian black wolves, with one such Russian wolf (a gray male heterozygous recessive carrier who sired black offspring with a domestic black sheepdog) was identified in studies conducted in the 1920s by a Russian biologist. [25]
Scientists have recently discovered a melanistic Indian wolf, a member of the lineage of wolves that has been described by some scientists as "the oldest lineage of wolves". [26] These scientists (Lokhande and Bajaru) have argued that the presence of melanistic Indian wolves may indicate that the cause of wolf melanism may be more complex than the hypothesis that a single gene for melanism in ancient Old World wolves was acquired by domestic dogs, then lost in wild wolf populations, and then reintroduced into wild wolf populations by interbreeding with domestic dogs. These scientists argue that the melanistic Indian wolf "challenges the hypothesis of complete disappearance of the gene responsible for the black coat colour from the gene pool of the Old World wolves" and "may indicate the recent re-introduction of the gene from dogs to Indian wolves through hybridisation, or recurrence of an independent mutation in Indian wolves." [26]
As black-coloured wolves occur more frequently in forested areas than on the tundra (black coats occur in about 62% of wolves in the forested areas of the Canadian Arctic, compared with about 7% in the icy tundra [20] ), melanism was concluded by the researchers to give those wolves an adaptive advantage. The mutation's purpose has not yet been identified. Dr. Barsh ruled out camouflage, as wolves have few natural predators, and there is no evidence that a black coat colour leads to any increase in hunting success rates. [19] Dr. Barsh observed that beta-defensin is involved in providing immunity to viral and bacterial skin infections, which might be more common in forested, warmer environments. [1] It has been suggested that the mutation's association with forested habitats means that the prevalence of melanism should increase as forests expand northward. [27] Dark fur is believed to be dominant in wolves. [27] [28] A mating between a black and a gray wolf resulted in 10 pups with dark fur out of a total of 14. [27]
Black wolves rarely occur in Europe and Asia, where interactions with domestic dogs have been reduced over the past thousand years due to the depletion of wild wolf populations. [29] They have occasionally appeared, as wolf-dog hybrids are known in Russia as "black wolves", [30] and currently, 20–25% of Italy's wolf population is composed of black animals. [31] They are more common in North America; about half of the wolves in the reintroduced wolf population in Wyoming's Yellowstone National Park are black. Like Pyrenean wolves, black wolves do not live in France. [29] In southern Canada and Minnesota, the black phase is more common than the white, though gray-coloured wolves predominate. [32]
The wolf, also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of Canis lupus have been recognized, including the dog and dingo, though gray wolves, as popularly understood, only comprise naturally-occurring wild subspecies. The wolf is the largest extant member of the family Canidae, and is further distinguished from other Canis species by its less pointed ears and muzzle, as well as a shorter torso and a longer tail. The wolf is nonetheless related closely enough to smaller Canis species, such as the coyote and the golden jackal, to produce fertile hybrids with them. The wolf's fur is usually mottled white, brown, gray, and black, although subspecies in the arctic region may be nearly all white.
A wolfdog is a canine produced by the mating of a domestic dog with a gray wolf, eastern wolf, red wolf, or Ethiopian wolf to produce a hybrid.
Melanism is the congenital excess of melanin in an organism resulting in dark pigment.
Equine coat color genetics determine a horse's coat color. Many colors are possible, but all variations are produced by changes in only a few genes. Bay is the most common color of horse, followed by black and chestnut. A change at the agouti locus is capable of turning bay to black, while a mutation at the extension locus can turn bay or black to chestnut.
The golden jackal, also called common jackal, is a wolf-like canid that is native to Eurasia. The golden jackal's coat varies in color from a pale creamy yellow in summer to a dark tawny beige in winter. It is smaller and has shorter legs, a shorter tail, a more elongated torso, a less-prominent forehead, and a narrower and more pointed muzzle than the Arabian wolf. It is listed as Least Concern on the IUCN Red List due to its widespread distribution and high density in areas with plenty of available food and optimum shelter.
A coydog is a canid hybrid resulting from a mating between a male coyote and a female dog. Hybrids of both sexes are fertile and can be successfully bred through four generations. Similarly, a dogote is a hybrid with a dog father and a coyote mother.
A coywolf is a canid hybrid descended from coyotes, eastern wolves, gray wolves, and dogs. All of these species are members of the genus Canis with 78 chromosomes; they therefore can interbreed. One genetic study indicates that these species genetically diverged relatively recently. Genomic studies indicate that nearly all North American gray wolf populations possess some degree of admixture with coyotes following a geographic cline, with the lowest levels occurring in Alaska, and the highest in Ontario and Quebec, as well as Atlantic Canada. Another term for these hybrids is sometimes wolfote.
Canid hybrids are the result of interbreeding between the species of the subfamily Caninae.
Black squirrels are a melanistic subgroup of squirrels with black coloration on their fur. The phenomenon occurs with several species of squirrels, although it is most frequent with the eastern gray squirrel and the fox squirrel. Black morphs of the eastern gray and fox squirrels are the result of a variant pigment gene. Several theories have surfaced as to why the black morph occurs, with some suggesting that the black morph is a selective advantage for squirrels inhabiting the northern ranges of the species, with the black fur providing a thermal advantage over its non-melanistic counterpart.
The domestication of the dog was the process which led to the domestic dog. This included the dog's genetic divergence from the wolf, its domestication, and the emergence of the first dogs. Genetic studies suggest that all ancient and modern dogs share a common ancestry and descended from an ancient, now-extinct wolf population – or closely related wolf populations – which was distinct from the modern wolf lineage. The dog's similarity to the grey wolf is the result of substantial dog-into-wolf gene flow, with the modern grey wolf being the dog's nearest living relative. An extinct Late Pleistocene wolf may have been the ancestor of the dog.
The Indian wolf is a subspecies of gray wolf that ranges from Southwest Asia to the Indian subcontinent. It is intermediate in size between the Himalayan wolf and the Arabian wolf, and lacks the former's luxuriant winter coat due to it living in warmer conditions. Within this subspecies, the "Indian plains wolf" is genetically basal to all other extant Canis lupus apart from the older-lineage Himalayan wolf, with both proposed as separate species. The Indian wolf travels in smaller packs and is less vocal than other variants of the gray wolf, and has a reputation for being cunning. The Indian wolf is one of the most endangered populations of gray wolf in the world.
The genetic basis of coat colour in the Labrador Retriever has been found to depend on several distinct genes. The interplay among these genes is used as an example of epistasis.
Amelanism is a pigmentation abnormality characterized by the lack of pigments called melanins, commonly associated with a genetic loss of tyrosinase function. Amelanism can affect fish, amphibians, reptiles, birds, and mammals including humans. The appearance of an amelanistic animal depends on the remaining non-melanin pigments. The opposite of amelanism is melanism, a higher percentage of melanin.
A melanistic mask is a dog coat pattern that gives the appearance of a mask on the dog's face. The hairs on the muzzle, and sometimes entire face or ears, are colored by eumelanin instead of pheomelanin pigment. Eumelanin is typically black, but may instead be brown, dark gray, or light gray-brown. Pheomelanin ranges in color from pale cream to mahogany. The trait is caused by M264V (EM), a completely dominant allele (form) of the melanocortin 1 receptor gene.
Colours of the Syrian hamster can be described in three ways: as "self", "agouti" or "combinations". Self colours are a consistent coat colour with the same colour topcoat and undercoat. Agouti hamsters have a ticked coat, where each individual fur is banded in different colours. Agouti hamsters also have "agouti markings" which consist of dark cheek markings, a dark marking on the head, and a light underbelly. Combinations are produced when two self or agouti colours are present.
Agouti is a type of fur coloration in which each hair displays two or more bands of pigmentation. The overall appearance of agouti fur is usually gray or dull brown, although dull yellow is also possible.
The Pleistocene wolf, also referred to as the Late Pleistocene wolf, is an extinct lineage or ecomorph of the grey wolf. It was a Late Pleistocene 129 Ka – early Holocene 11 Ka hypercarnivore. While comparable in size to a large modern grey wolf, it possessed a shorter, broader palate with large carnassial teeth relative to its overall skull size, allowing it to prey and scavenge on Pleistocene megafauna. Such an adaptation is an example of phenotypic plasticity. It was once distributed across the northern Holarctic. Phylogenetic evidence indicates that despite being much smaller than this prehistoric wolf, the Japanese wolf, which went extinct in the early 20th century, was of a Pleistocene wolf lineage, thus extending its survival to several millennia after its previous estimated extinction around 7,500 years ago.
The evolution of the wolf occurred over a geologic time scale of at least 300 thousand years. The grey wolf Canis lupus is a highly adaptable species that is able to exist in a range of environments and which possesses a wide distribution across the Holarctic. Studies of modern grey wolves have identified distinct sub-populations that live in close proximity to each other. This variation in sub-populations is closely linked to differences in habitat – precipitation, temperature, vegetation, and prey specialization – which affect cranio-dental plasticity.
Dogs have a wide range of coat colors, patterns, textures and lengths. Dog coat color is governed by how genes are passed from dogs to their puppies and how those genes are expressed in each dog. Dogs have about 19,000 genes in their genome but only a handful affect the physical variations in their coats. Most genes come in pairs, one being from the dog's mother and one being from its father. Genes of interest have more than one expression of an allele. Usually only one, or a small number of alleles exist for each gene. In any one gene locus a dog will either be homozygous where the gene is made of two identical alleles or heterozygous where the gene is made of two different alleles.
The agouti gene, the Agouti-signaling protein (ASIP) is responsible for variations in color in many species. Agouti works with extension to regulate the color of melanin which is produced in hairs. The agouti protein causes red to yellow pheomelanin to be produced, while the competing molecule α-MSH signals production of brown to black eumelanin. In wildtype mice, alternating cycles of agouti and α-MSH production cause agouti coloration. Each hair has bands of yellow which grew during agouti production, and black which grew during α-MSH production. Wildtype mice also have light-colored bellies. The hairs there are a creamy color the whole length because the agouti protein was produced the whole time the hairs were growing.