Dog Pen Definition
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The gray wolf or grey wolf (Canis lupus) is a species of canid native to the wilderness and remote areas of North America, Eurasia, and North Africa. It is the largest member of its family, with males averaging 43–45 kg (95–99 lb), and females 36–38.5 kg (79–85 lb).[3] It is similar in general appearance and proportions to a German shepherd,[4] or sled dog, but has a larger head, narrower chest, longer legs, straighter tail and bigger paws.[5] Its winter fur is long and bushy, and predominantly a mottled gray in colour, although nearly pure white, red, or brown to black also occur.[4]
Within the genus Canis, the gray wolf represents a more specialised and progressive form than its smaller cousins (the coyote and golden jackal), as demonstrated by its morphological adaptations to hunting large prey, its more gregarious nature[6] and its highly advanced expressive behavior.[7][8] It is a social animal, travelling in nuclear families consisting of a mated pair, accompanied by the pair's adult offspring.[9] The gray wolf is typically an apex predator throughout its range, with only humans and tigers[10][11][12][13] posing a serious threat to it. It feeds primarily on large ungulates, though it also eats smaller animals, livestock, carrion, and garbage.[14]
The gray wolf is one of the world's most well researched animals, with probably more books written about it than any other wildlife species.[15] It has a long history of association with humans, having been despised and hunted in most agricultural communities due to its attacks on livestock, while conversely being respected by some Native American tribes.[14] It is the sole ancestor of the dog, which was first domesticated in the Middle East.[16] Although the fear of wolves is prevalent in many human societies, the majority of recorded attacks on people have been attributed to animals suffering from rabies. Non-rabid wolves have attacked and killed people, mainly children, but this is unusual, as wolves are relatively few, live away from people, and have been taught to fear humans by hunters and shepherds.[17] Hunting and trapping has reduced the species' range to about one third of its original range, though its still relatively widespread range and stable population means that the species is not threatened at a global level, and is therefore classified by the IUCN as Least Concern.[1]
Contents [hide]
1 Etymology
2 Evolution and taxonomy
2.1 Origins
2.1.1 Ancestry
2.1.2 Subspeciation
2.1.3 Colonization of North America
2.2 Subspecies
2.3 Domestication
2.4 Hybridization
2.4.1 Hybridization with dogs
2.4.2 Hybridization with coyotes and golden jackals
3 Physical description
3.1 Anatomy
3.2 Dimensions
3.3 Fur
3.4 Sensory abilities
4 Behaviour
4.1 Social and territorial behaviors
4.2 Reproduction and development
4.3 Denning and sheltering behaviour
4.4 Intelligence
4.5 Hunting and feeding behaviours
5 Communication
5.1 Visual
5.2 Auditory
5.2.1 Howling
5.2.2 Other vocalizations
5.3 Olfactory
6 Ecology
6.1 Diet
6.2 Enemies and competitors
7 Range and conservation
7.1 Europe
7.1.1 Decline
7.1.2 Recovery
7.2 Asia
7.2.1 Historical range and decline
7.2.2 Modern range
7.3 North America
7.3.1 Historical range and decline
7.3.2 Modern range
7.4 Africa
8 Diseases and parasites
8.1 Viral and bacterial infections
8.2 Parasitic infections
9 Relationships with humans
9.1 In culture
9.1.1 In mythology and folklore
9.1.2 In fable and literature
9.1.3 In heraldry and symbolism
9.2 Livestock and dog predation
9.3 Attacks on humans
9.4 Hunting
9.5 Uses
9.6 Wolves as pets
10 See also
11 Notes
12 References
13 Bibliography
14 Further reading
15 External links
Etymology
The English word "wolf" stems from the Old English wulf, which is itself thought to be derived from the Proto-Germanic *wulfaz, from the Proto-Indo-European root *wlqwos/*lukwos.[18] Old English literature contains several instances of Anglo-Saxon kings and warriors taking on wulf as a prefix or suffix in their names. Examples include Wulfhere, Cynewulf, Ceonwulf, Wulfheard, Eanwulf, Wulfmeer, Wulfstan and Aethelwulf. Wolf-related names were also common among pre-Christian Germanic warriors: Wolfhroc (Wolf-Frock), Wolfhetan (Wolf Hide), Isangrim (Grey Mask), Scrutolf (Garb Wolf), Wolfgang (Wolf Gait) and Wolfdregil (Wolf Runner).[19]
Evolution and taxonomy
Timeline of canids including Canis lupus in red (Tedford & Xiaoming Wang)
Origins
Ancestry
The species' most likely ancestral candidate is Canis lepophagus, a small, narrow skulled North American canid of the Miocene era, which may have also given rise to the coyote.[20] After the extinction of the large bodied Borophaginae family, C. lepophagus developed into a larger, broader-skulled animal. Fossils of this larger form of C. lepophagus found in northern Texas may represent the ancestral stock from which true wolves derive.[21] The first true wolves began to appear at the end of the Blancan North American Stage and the onset of the early Irvingtonian. Among them was C. priscolatrans, a small species closely resembling the modern-day red wolf, which colonised Eurasia by crossing the Bering land bridge. The new Eurasian C. priscolatrans population gradually evolved into C. mosbachensis,[20] which closely resembled modern wolves found in the Arabian Peninsula and South Asia, which were once distributed in Europe in the early Quaternary glaciation until about 500,000 years ago (see Subspecies).[22] C. mosbachensis subsequently evolved in the direction of C. lupus.[20]
Subspeciation
The African wolf (C. l. lupaster) represents the oldest extant lineage of the species[23]
MtDNA studies have shown that there are at least four distinct gray wolf lineages: the most ancient is that of the African wolf (native to North, West, and East Africa), which is thought to have originated as early as the Middle to Late Pleistocene.[23] All other lineages occur together in the Indian Subcontinent, the oldest of which is the Himalayan wolf (native to the Himalayan region of eastern Kashmir, Himachal Pradesh, parts of Tibet and eastern Nepal), which is thought to have originated 800,000 years ago, when the Himalayan region was going through major geologic and climatic upheaval. The peninsular Indian wolf, C. l. pallipes, likely diverged from the Himalayan wolf 400,000 years ago.[24][25] The youngest wolf lineage in India is represented by C. l. chanco (native to the northwestern Himalayan region of Kashmir), which originated 150,000 years ago. This last lineage, known as the Holarctic clade, expanded into Europe and North America, as shown by it sharing genetic markers with domestic dogs, European and North American wolves.[24][25]
The now extinct Japanese wolves were descended from large Siberian wolves which colonised the Korean Peninsula and Japan, before it separated from mainland Asia, 20,000 years ago during the Pleistocene. During the Holocene, the Tsugaru Strait widened and isolated Honshu from Hokkaidō, thus causing climatic changes leading to the extinction of most large bodied ungulates inhabiting the archipelago. Japanese wolves likely underwent a process of island dwarfism 7,000–13,000 years ago in response to these climatological and ecological pressures. C. l. hattai (formerly native to Hokkaidō) was significantly larger than its southern cousin C. l. hodophilax, as it inhabited higher elevations and had access to larger prey, as well as a continuing genetic interaction with dispersing wolves from Siberia.[26]
Colonization of North America
Canis lupus colonized North America during the late Rancholabrean era.[27] The larger Canis dirus was already established there, but it became extinct 8,000 years ago, after the large prey it relied on disappeared. Competition with the newly arrived gray wolf for the smaller and swifter prey that survived may have contributed to its decline. With the extinction of the dire wolf, the gray wolf became the only large and widespread canid species left.[20] The North American recolonisation likely occurred in several waves, with the most distinctive populations occurring in the periphery of the range. These populations (C. l. arctos on the high arctic islands, C. l. lycaon in the eastern forests, and C. l. baileyi in the far south) may represent survivors of early migrations from Eurasia. C. l. baileyi and C. l. lycaon display some primitive traits and systematic affinity to one another. Fossil remains from the late Pleistocene of large bodied wolves similar to C. l. arctos and C. l. albus occur in coastal southern California, indicating that large North American gray wolf subspecies were once widespread, and may have been driven southward by glaciation, though wolves no longer reside there. Fossils of small bodied wolves similar to C. l. baileyi have been found in a range encompassing Kansas and southern California. This indicates a late Pleistocene population flux, in which large, Arctic forms of wolf moved farther south, with smaller, warmth adapted wolves expanding as the climate moderated.[27]
Subspecies
Main article: Subspecies of Canis lupus
Eurasian wolf (Canis lupus lupus), an example of the "northern" wolf clade
Arabian wolf (Canis lupus arabs), an example of the "southern" wolf clade
As of 2005,[28] 37 subspecies of gray wolf are recognised by MSW3. Included among them are the domestic dog and the dingo, as well as the Eastern wolf of Algonquin Provincial Park and the red wolf of North Carolina. Once thought to be unique species, SNP studies show that the red and Eastern wolf are in fact the results of varying degrees of wolf–coyote hybridization stretching back to only a few centuries. The Eastern wolf is on average 58% gray wolf, while the red wolf is only 20–24%.[29] Phylogenetic comparisons of the MtDNA sequences of both wolves and golden jackals in 2011 demonstrated that the African wolf, which was once thought to be a golden jackal, is in fact a subspecies of gray wolf.[30]
Wolf subspecies are divided into two categories:
"Northern wolves": large-sized, large-brained wolves with strong carnassials which inhabit North America, Europe and northern Asia.[31]
"Southern wolves": native to the Arabian Peninsula, South Asia and possibly North Africa. They are characterised by their smaller size, skull and teeth, and a short and thin coat without appreciable underwool.[32] They may represent a relict population of early wolves, as they closely resemble fossil European wolves.[22] The rate of changes observed in their DNA sequences date them to about 800,000 years, as opposed to the American and European lineages which stretch back only 150,000.[33] The vocalisations of southern wolves have a higher proportion of short, sharp barking,[31] and they seldom howl.[34] It is likely that dogs and dingoes stem from this group.[31][35]
Wolves in Central and East Asia are intermediate in form and size to northern and southern wolves.[22] Differences in brain size are well defined in different wolf populations, with wolves in northern Eurasia having the highest values, North American wolves having slightly smaller brains, and the southern wolves having the smallest (about 5–10% smaller than those of northern wolves).[36]
Skulls of a St. Bernard dog and a lap dog. Though varied in appearance, domestic dog skulls can be consistently distinguished from wolf skulls by their shortened muzzles, broader palates, crowded teeth and the broad, heavy frontal shields at the top of their skulls.[37]
Domestication
Main article: Origin of the domestic dog
Morphological comparisons between wolves and domestic dogs have narrowed the likely ancestral subspecies of gray wolf to Middle Eastern and South Asian wolves.[22] This is confirmed by SNP studies done in 2010, which point to the Middle East as the source of most of the genetic diversity in the domestic dog and the most likely origin of domestication events.[16] The actual process undergone in domesticating the wolf is still debated. Although it is popularly assumed that dogs originated as a result of artificial selection, the general intractability of adult wolves to human handling has led certain experts to theorise that the domestication process occurred through natural selection, when Mesolithic human communities began building permanent settlements in which a new ecological niche (middens and landfills) was opened to wolves. These wolves would have formed a commensal relationship with humans, feeding on their waste over many generations, with natural selection favouring assertive wolves with shorter flight distances in human presence, and causing physical changes related to the redundancy of features adapted for hunting big game.[38]
Although dogs are the wolf's closest relative (the genetic divergence between gray wolves and dogs is only 1.8%, as opposed to over 4% between gray wolves, Ethiopian wolves and coyotes),[39] comparative studies on dog and wolf behaviour and anatomy have shown that dog physiology and most dog behaviours are comparable to those of young wolves, an example of neoteny and pedomorphism.[40] The tympanic bullae are large, convex and almost spherical in wolves, while the bullae of dogs are smaller, compressed and slightly crumpled.[41] Compared to equally sized dogs, wolves tend to have 20% larger skulls and 10% bigger brains.[42] This reduction lies in the parts of the brain that deal with sense impressions.[43] The teeth of wolves are also proportionately larger than those of dogs; premolars and molars of wolves are much less crowded, and have more complex cusp patterns.[44] Dogs lack a functioning pre-caudal gland, and most enter estrus twice yearly, unlike wolves which only do so once annually.[37]
Hybridization
See also: Canid hybrids
Hybridization with dogs
Main articles: Wolfdog and black wolf
Arctic wolf/Alaskan malamute hybrid, Lobo Park, Antequera, Spain
Although dogs and wolves are genetically very close, and have shared vast portions of their ranges for millennia, the two generally do not voluntarily interbreed in the wild,[37] though lone wolves may fraternise with guard or herding dogs as surrogate pack members.[45] They can produce viable offspring, with all subsequent generations being fertile.[37] In North America, black colored wolves acquired their coloration from wolf-dog hybridization, which occurred 10,000–15,000 years ago.[46] Although wolf-dog hybridisation in Europe has raised concern among conservation groups fearing for the wolf's purity, an analysis on the mtDNA sequences show that introgression of dog genes into European wolf populations does not pose a significant threat. Also, as wolf and dog mating seasons do not fully coincide, the likelihood of wild wolves and dogs mating and producing surviving offspring is small.[47] Like pure wolves, hybrids breed annually, though their mating season occurs three months earlier, with pups mostly being born in the winter period, thus lessening their chances of survival.[37]
Although it is popularly believed that some Inuit tribes mate their sled dogs to wolves in order to improve their stamina, this is probably untrue, as wolf hybrids are generally unable to cooperate effectively in pulling harnesses, and their stamina is much less than that of sled dogs.[48] The captive breeding of wolf-dog hybrids has proliferated in the USA, with 300,000 such animals being present there.[37] The most commonly used dog breeds for this purpose are of the spitz group.[49] At least two wolf-dog breeds have been created in Europe, the Saarlooswolfhond and the Czechoslovakian Wolfdog, both by crossing wolves with German shepherds.[49]
The red wolf, a coyote with distant wolf ancestry[29]
Hybridization with coyotes and golden jackals
Main articles: Coywolf, Canis latrans "var.", eastern wolf, and red wolf
Numerous genetic studies indicate that North American gray wolves have hybridized with coyotes in varying degrees in different areas. Studies on mtDNA and microsatellite loci indicate that wolves have hybridized extensively with coyotes in the northeastern USA and southeastern Canada, with the frequency of coyote haplotypes in wolves tending to increase to the east, from 50% in Minnesota, to 100% in southern Quebec.[50] These hybrids are smaller than wolves, and hold smaller territories, but are in turn larger and hold more extensive territories than coyotes.[51] In 2011, an analysis of 48,000 SNP chips in the genomes of various wolf and coyote populations revealed that the eastern wolf (native to Algonquin Provincial Park) and the red wolf (native to North Carolina), both previously labeled as species distinct from the gray wolf, are in fact products of varying degrees of wolf-coyote hybridization. The wolf-coyote admixture resulting in the development of the eastern wolf may have occurred on the order of 600–900 years ago between gray wolves and a now extinct pre-Columbian coyote population. The eastern wolf has since backcrossed extensively with parent gray wolf populations. The red wolf may have originated later, approximately 287–430 years ago, when much of the southeastern USA was being converted to agriculture and predators were targeted for extermination. During this period, declining local wolf populations would have been forced to mate with coyotes, with the resulting hybrids backcrossing to coyotes as the wolves disappeared, to the extent that ~75–80% of the modern red wolf's genome is of coyote derivation.[29] Although hybridization between wolves and golden jackals has never been observed, evidence of such occurrences was discovered through mtDNA analysis on jackals in Senegal.[23]
Physical description
Wolf skeleton, Museo del Lupo, Abruzzo National Park, Italy
Anatomy
See also: Dog anatomy
The gray wolf is a slender, powerfully built animal with a large, deeply descending ribcage and a sloping back. Its abdomen is pulled in, and its neck heavily muscled. Its limbs are long and robust, with comparatively small paws.[52] The front paws have five toes each, while the back paws have four. The forelimbs are seemingly pressed into the chest, with the elbows pointed inward, and the feet outward, thus allowing both fore and hind limbs on the same side to swing in the same line. The wolf's legs are moderately longer than those of other canids. This enables the animal to move swiftly, and allows it to overcome the deep snow that covers most of its geographical range.[53] Females tend to have narrower muzzles and foreheads, thinner necks, slightly shorter legs and less massive shoulders than males.[54] Compared to its smaller cousins (the coyote and golden jackal), the gray wolf is larger and heavier, with a broader snout, shorter ears, a shorter torso and longer tail.[23][41][55]
Wolf trotting, Denali National Park. When moving, the wolf generally places its hind paws in the tracks made by the front paws.[53]
The gray wolf's head is large and heavy, with a wide forehead, strong jaws and a long, blunt muzzle. The ears are relatively small and triangular.[52] The teeth are heavy and large, being better suited to crushing bone than those of other extant canids, though not as specialised as those found in hyenas.[56][57] The canine teeth are robust and relatively short (26 mm).[41] The wolf can exert a crushing pressure of perhaps 1,500 lbf/in2 compared to 750 lbf/in2 for a German shepherd. This force is sufficient to break open most bones.[58] In cold climates, the wolf can reduce the flow of blood near its skin to conserve body heat. The warmth of the footpads is regulated independently of the rest of the body, and is maintained at just above tissue-freezing point where the pads come in contact with ice and snow.[59]
The gray wolf usually carries its head at the same level as the back, raising it only when alert.[52] It usually travels at a loping pace, placing its paws one directly in front of the other. This gait can be maintained for hours at a rate of 8–9 km/hr,[60] and allows the wolf to cover great distances. On bare paths, a wolf can quickly achieve speeds of 50–60 km/hr. A running wolf holds its head slightly low and cocked to one side, directing one ear forward and the other back. This posture allows the wolf to continually make use of its exceptional hearing.
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