British Pleistocene Mammalia (1866) Wolf Cranium

The evolution of the wolf occurred over a

geologic time scale The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochr ...

of at least 300 thousand years. The

grey wolf The wolf (''Canis lupus''; : wolves), 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, and gray wolves, as popularly ...

''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 The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...

Fossil record

The fossil record for ancient vertebrates is composed of rarely occurring fragments from which it is often impossible to obtain genetic material. Researchers are limited to morphologic analysis but it is difficult to estimate the intra-species and inter-species variations and relationships that existed between specimens across time and place. Some observations are debated by researchers who do not always agree, and hypotheses that are supported by some authors are challenged by others. The

Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...

occurred 65 million years ago and brought an end to the dinosaurs and the appearance of the first carnivorans. The name carnivoran is given to a member of the order Carnivora. Carnivorans possess a common arrangement of teeth called

carnassials Carnassials are paired upper and lower teeth modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner. This adaptation is found in carnivorans, where the carnassials are the modified f ...

, in which the first lower molar and the last upper premolar possess blade-like enamel

crowns A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...

that act similar to a pair of shears for cutting meat. This dental arrangement has been modified by adaptation over the past 60 million years for diets composed of meat, for crushing vegetation, or for the loss of the carnassial function altogether as in seals, sea lions, and walruses. Today, not all carnivorans are

carnivores A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other so ...

, such as the insect-eating

Aardwolf The aardwolf (''Proteles cristata'') is an insectivorous species of hyena, native to East and Southern Africa. Its name means "earth-wolf" in Afrikaans and Dutch. It is also called maanhaar-jackal (Afrikaans for " mane-jackal"), termite-eat ...

. The carnivoran ancestors of the dog-like

caniforms Caniformia is a suborder within the order Carnivora consisting of "dog-like" carnivorans. They include dogs (wolves, foxes, etc.), bears, raccoons, and mustelids. The Pinnipedia (seals, walruses and sea lions) are also assigned to this group. ...

and the cat-like

feliforms Feliformia is a suborder within the order Carnivora consisting of "cat-like" carnivorans, including cats (large and small), hyenas, mongooses, viverrids, and related taxa. Feliformia stands in contrast to the other suborder of Carnivora, Canifor ...

began their separate evolutionary paths just after the end of the dinosaurs. The first members of the dog family Canidae appeared 40 million years ago, of which only its subfamily the

Caninae The Caninae, known as canines, are one of three subfamilies found within the canid family. The other two canid subfamilies are the extinct Borophaginae and Hesperocyoninae. The Caninae includes all living canids and their most recent fossil rel ...

survives today in the form of the wolf-like and fox-like canines. The caniforms included the fox-like genus '' Leptocyon'' whose various species existed from 34 million YBP before branching 11.9 million YBP into ''

Vulpes '' Vulpes '' is a genus of the sub-family Caninae. The members of this genus are colloquially referred to as true foxes, meaning they form a proper clade. The word " fox" occurs in the common names of all species of the genus, but also appea ...

'' (foxes) and Canini (canines). The jackal-sized ''

Eucyon ''Eucyon'' (Greek: : good, true; : dog) is an extinct genus of medium omnivorous coyote-like canid that first appeared in the Western United States during the late Middle Miocene 10 million years ago. It was the size of a jackal and weighed ...

'' existed in North America from 10 million YBP and by the

Early Pliocene Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early ...

about 6–5 million YBP the coyote-like ''

Eucyon davisi ''Eucyon'' (Greek: : good, true; : dog) is an extinct genus of medium omnivorous coyote-like canid that first appeared in the Western United States during the late Middle Miocene 10 million years ago. It was the size of a jackal and weighed ar ...

'' invaded Eurasia. In North America it gave rise to early ''Canis'' which first appeared in the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

(6 million YBP) in south-western US and Mexico. By 5 million YBP the larger ''

Canis lepophagus ''Canis lepophagus'' (Latin: : 'dog'; : 'hare' or 'rabbit'; suffix : '-eating'; hence hare-eating dog) is an extinct species of canid which was endemic to much of North America during the Early Pliocene. It is notable because its lineage is prop ...

'' appeared in the same region. The canids that had immigrated from North America to Eurasia – ''

'', ''

'', and ''

Nyctereutes ''Nyctereutes'' (Greek: ''nyx, nykt-'' "night" + ''ereutēs'' "wanderer") is a genus of canid which includes only two extant species both known as raccoon dogs; the common raccoon dog (''Nyctereutes procyonoides'') and the Japanese raccoon dog (' ...

'' – were small to medium-sized predators during the Late Miocene and Early Pliocene but they were not the top predators. The position of the canids would change with the arrival of ''Canis'' to become a dominant predator across the

. The wolf-sized '' C. chihliensis'' appeared in northern China in the Mid-Pliocene around 4–3 million YBP. The large wolf-sized ''Canis'' appeared in the Middle

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Shanxi Province, China. By 2.5 million years ago its range included the Nihewan Basin in Yangyuan County,

Hebei Hebei or , (; alternately Hopeh) is a northern province of China. Hebei is China's sixth most populous province, with over 75 million people. Shijiazhuang is the capital city. The province is 96% Han Chinese, 3% Manchu, 0.8% Hui, and 0 ...

, China and Kuruksay, Tadzhikistan. This was followed by an explosion of ''Canis'' evolution across Eurasia in the Early Pleistocene around 1.8 million YBP in what is commonly referred to as the ''wolf event''. It is associated with the formation of the

mammoth steppe During the Last Glacial Maximum, the mammoth steppe, also known as steppe-tundra, was the Earth's most extensive biome. It spanned from Spain eastward across Eurasia to Canada and from the arctic islands southward to China. The mammoth steppe ...

and continental glaciation. ''Canis'' spread to Europe in the forms of '' C. arnensis'', '' C. etruscus'', and '' C. falconeri''. Other studies state that the oldest ''Canis'' remains that have been found in Europe were from France and dated to 3.1 million YBP, followed by ''Canis cf. etruscus'' (where

cf. The abbreviation ''cf.'' (short for the la, confer/conferatur, both meaning "compare") is used in writing to refer the reader to other material to make a comparison with the topic being discussed. Style guides recommend that ''cf.'' be used onl ...

in Latin means confer, uncertain) from Italy dated to 2.2 million YBP. The fossil record is incomplete but it is likely that wolves arose from a population of small, early canids. Morphological evidence and genetic evidence both suggest that wolves evolved during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

eras from the same lineage that also led to the coyote, with fossil specimens indicating that the coyote and the wolf diverged from a common ancestor 1.5 million years ago. The ancestor of the jackal and the other extant members of the genus ''Canis'' had split from the lineage before this time. After this separation from a common ancestor the species that were believed to be involved in the further evolution of the wolf and coyote – and the beliefs of some

paleontologists Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...

– diverged. A number of researchers believed that the lines of '' C. priscolatrans'', ''C. etruscus'', '' C. rufus'', '' C. lycaon'', and '' C. lupus'' were components involved in some way that lead to the modern wolf and coyote.

''Canis lepophagus''

'' lived in the early Pliocene in North America. Kurten proposed that the Blancan ''C. lepophagus'' derived from smaller

''Canis'' species in North America. It then became widespread across Eurasia where it was either identical to, or closely related with, ''C. arnensis'' of Europe. Johnston describes ''C. lepophagus'' as having a more slender skull and skeleton than in the modern coyote. Robert M. Nowak found that the early populations had small, delicate and narrowly proportioned skulls that resemble small coyotes and appear to be ancestral to '' C. latrans''. Johnson noted that some specimens found in Cita Canyon, Texas, had larger, broader skulls, and along with other fragments Nowak suggested that these were evolving into wolves. Tedford disagreed with previous authors and found that its cranio-dental morphology lacked some characteristics that are shared by ''C. lupus'' and ''C. latrans'', and therefore there was not a close relationship but it did suggest ''C. lepophagus'' was the ancestor of both wolves and coyotes.

''Canis priscolatrans''

''Canis priscolatrans'' lived in the late Pliocene-Early Pleistocene in North America. The first definite wolf appeared in the Late Blancan/Early Irvingtonian, and named ''C. priscolatrans'' that was either very close to or a synonym for ''

Canis edwardii ''Canis edwardii'', also known as Edward's wolf, is an extinct species of wolf in the genus ''Canis'' which was endemic to North America three million years ago from the Late Blancan stage of the Pliocene epoch and was extinct by the end of the I ...

''. It resembled ''C. rufus'' in cranial size and proportions but with more complex dentition. However, there are no fossils of ''C. rufus'' until the Late Rancholabrean. Kurtén was uncertain if ''C. priscolatrans'' derived from ''C. lepophagus'' and ''C. arnensis'', but believed that ''C. priscolatrans'' was a population of large coyotes that were ancestral to

Rancholabrean The Rancholabrean North American Land Mammal Age on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from less than 240,000 years to 11,000 years BP, a pe ...

and recent ''C. latrans''. He noted that ''C. arnensis'' of Europe showed striking similarities to ''C. priscolatrans'', and they could represent what once was a holarctic population of coyotes. Nowak disagreed, and believed that ''C. priscolatrans'' was a counterpart to the European ''C. etruscus''. Kurtén later proposed that both ''C. priscolatrans'' and ''C. etruscus'' were part of a group which led to ''C. lupus'' but was not sure if they evolved separately from ''C. lepophagus'' or a possible common ancestor that was derived from ''C. lepophagus''. The remains of the larger coyote-like ''Canis edwardii'' have been found in the later

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58C. armbrusteri''. during the Middle Pleistocene in North America. Robert A. Martin disagreed, and believed that ''C. armbrusteri'' was ''C. lupus''. Nowak disagreed with Martin and proposed that ''C. armbrusteri'' was not related to ''C. lupus'' but ''C. priscolatrans'', which then gave rise to '' A. dirus''. Tedford proposed that the South American '' C. gezi'' and '' C. nehringi'' share dental and cranial similarities developed for hypercarnivory, suggesting ''C. armbrusteri'' was the common ancestor of ''C. gezi'', ''C. nehringi'' and ''A. dirus''.

''Aenocyon dirus''

In 1908 the paleontologist

John Campbell Merriam John Campbell Merriam (October 20, 1869 – October 30, 1945) was an American paleontologist, educator, and conservationist. The first vertebrate paleontologist on the West Coast of the United States, he is best known for his taxonomy of ver ...

began retrieving numerous fossilized bone fragments of a large wolf from the Rancho LaBrea tar pits. By 1912 he had found a skeleton sufficiently complete to be able to formally recognize these and the previously found specimens under the name ''C.dirus'' (Leidy 1858). ''Canis dirus'', or as it is now widely recognized, ''Aenocyon dirus'', lived in the late Pleistocene to early Holocene in North and South America. In 1987, a new hypothesis proposed that a mammal population could give rise to a larger form called a hypermorph during times when food was abundant, but when food later became scarce the hypermorph would either adapt to a smaller form or go extinct. This hypothesis might explain the large body sizes found in many Late Pleistocene mammals compared to their modern counterparts. Both extinction and speciation – a new species splitting from an older one – could occur together during periods of climatic extremes. GloriaD.Goulet agreed with Martin and further proposed that this hypothesis might explain the sudden appearance of ''A.dirus'' in North America, and that because of the similarities in their skull shapes that ''C.lupus'' gave rise to the ''A.dirus'' hypermorph due to abundant game, a stable environment, and large competitors. Nowak, Kurten and Berta disagreed with Goulet and proposed that ''A. dirus'' was not derived from ''C. lupus''. The three noted paleontologists Xiaoming Wang, R. H. Tedford and R. M. Nowak have all proposed that ''A. dirus'' had evolved from ''C. armbrusteri'', with Nowak stating that there were specimens from Cumberland Cave, Maryland, that indicated ''C. armbrusteri'' diverging into ''A. dirus''. The two taxa share a number of characteristics (

synapomorphy In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

), which suggests an origin of ''A. dirus'' in the late Irvingtonian in the open terrain in the midcontinent, and then later expanding eastward and displacing its ancestor ''C. armbrusteri''. However, in 2021, a study indicated the dire wolf to be a highly divergent lineage which last shared a

most recent common ancestor In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...

with the wolf-like canines 5.7 million years ago. The morphological similarity between dire wolves and gray wolves was concluded to be due to

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

. This finding indicates that the wolf and coyote lineages evolved in isolation from the dire wolf lineage. The study proposes an early origin of the dire wolf lineage in the Americas, and that this geographic isolation allowed them to develop a degree of reproductive isolation since their divergence 5.7 million years ago. Coyotes, dholes, gray wolves, and the extinct ''

Xenocyon ''Xenocyon'' ("strange dog") is an extinct subgenus of ''Canis''. The group includes ''Canis'' (''Xenocyon'') ''africanus'', ''Canis'' (''Xenocyon'') ''antonii'' and ''Canis'' (''Xenocyon'') ''falconeri'' that gave rise to ''Canis'' (''Xenocyon'' ...

'' evolved in Eurasia and expanded into North America relatively recently during the Late Pleistocene, therefore there was no admixture with the dire wolf. As a result, the study found that the correct binomial name of the dire wolf is ''Aenocyon dirus'', as proposed by Merriam in 1918. The long-term isolation of the dire wolf lineage implies that other American fossil taxa, including ''C. armbrusteri'' and ''C. edwardii'', may also belong to the dire wolf's lineage.

''dirus–lupus'' hybrids

Merriam named 3 unusual species based on specimens recovered from the Rancho La Brea tar pits. They were regarded by Nowak as

taxonomic synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Lin ...

s for ''Canis lupus''. ''Canis occidentalis furlongi'' (Merriam 1910) was described as a wolf considerably smaller than the dire wolf and more closely related to the timber wolf ''

Canis lupus occidentalis The northwestern wolf (''Canis lupus occidentalis''), also known as the Mackenzie Valley wolf, Alaskan timber wolf, or Canadian timber wolf, is a subspecies of gray wolf in western North America. Arguably the largest grey wolf subspecies in the ...

''. However, its premolar P4 (upper

carnassial Carnassials are paired upper and lower teeth modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner. This adaptation is found in carnivorans, where the carnassials are the modified f ...

s) were massive, and the

hypocone A cusp is a pointed, projecting, or elevated feature. In animals, it is usually used to refer to raised points on the crowns of teeth. The concept is also used with regard to the leaflets of the four heart valves. The mitral valve, which has two ...

of the molar M1 was larger than that of the dire wolf. One specimen's teeth and palate are described as being between the dire wolf and ''Canis lupus occidentalis''. Nowak proposed the name ''Canis lupus furlongi'' as he believed that it was a subspecies of the grey wolf. There is the possibility that wolves living in marginal areas led to dire wolf/grey wolf hybrids. ''Canis milleri'' (Merriam 1912), the Miller wolf, was as large as the timber wolf but with a shorter and heavier head. Its skull and dentition were described as being intermediate between ''Canis lupus occidentalis'' and the dire wolf. Its skull differed from ''occidentalis'' due to its wider skull, especially at the palate, and the size of its P4 and M1 were much larger than any known timber wolf, with the P4 approaching that of the dire wolf in size. It is regarded by Nowak as a taxonomic synonym of ''Canis lupus furlongi''. ''Aenocyon milleri'' (Merriam 1918) was described as a wolf different from the dire wolf by its smaller size, low sagittal crest, and a less prominent inion, but closer to the dire wolf than the timber wolf. Only one specimen was found. It is regarded by Nowak as a taxonomic synonym of ''Canis lupus furlongi''.

''Canis mosbachensis''

Canis mosbachensis ''Canis mosbachensis'', sometimes known as the Mosbach wolf, is an extinct small wolf that once inhabited Eurasia from the Middle Pleistocene era to the Late Pleistocene. It is widely accepted as the ancestor of '' Canis lupus'', the grey wolf. ...

'', sometimes known as the Mosbach wolf, is an extinct small wolf that once inhabited Eurasia from the Middle to Late Pleistocene. The phylogenetic descent of the extant wolf ''C. lupus'' from ''C. etruscus'' through ''C. mosbachensis'' is widely accepted. In 2010, a study found that the diversity of the ''Canis'' group decreased by the end of the Early Pleistocene to

Middle Pleistocene The Chibanian, widely known by its previous designation of Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. Th ...

and was limited in Eurasia to the small wolves of the ''C. mosbachensis–C. variabilis'' group that were a comparable size to the extant

Indian wolf The Indian wolf (''Canis lupus pallipes'') 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 win ...

(''Canis lupus pallipes''), and the large hypercarnivorous ''Canis (Xenocyon) lycaonoides'' that was comparable in size to extant northern grey wolves.

''Canis variabilis''

In 2012, a study of the wolf-like ''Canis'' species of ancient China under the direction of Xiaoming Wang found that these were all quite close to ''C. lupus'' in both dental and post-cranial dimensions except for ''

Canis variabilis ''Canis mosbachensis'', sometimes known as the Mosbach wolf, is an extinct small wolf that once inhabited Eurasia from the Middle Pleistocene era to the Late Pleistocene. It is widely accepted as the ancestor of '' Canis lupus'', the grey wolf. ...

'', which was "very strange" compared to other ''Canis'' in China as it had much smaller cranio-dental dimensions than earlier and later species. The study concluded that "It is very likely that this species is the ancestor of the domestic dog ''Canis familiaris'', a hypothesis that has been proposed by previous authors."

''Canis chihliensis''

Wang Wang may refer to: Names * Wang (surname) (王), a common Chinese surname * Wāng (汪), a less common Chinese surname * Titles in Chinese nobility * A title in Korean nobility * A title in Mongolian nobility Places * Wang River in Thai ...

and

Tedford Richard Hall Tedford (April 25, 1929 – July 15, 2011) was Curator Emeritus in the Department of Vertebrate Paleontology of the American Museum of Natural History in New York City, having been named as curator in 1969.Staff"14 ARE APPOINTED AT MU ...

proposed that the genus ''Canis'' was the descendant of the coyote-like ''

davisi'', and its remains first appeared in the

(6 million YBP) in south-western USA and Mexico. By the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Canis lepophagus ''Canis lepophagus'' (Latin: : 'dog'; : 'hare' or 'rabbit'; suffix : '-eating'; hence hare-eating dog) is an extinct species of canid which was endemic to much of North America during the Early Pliocene. It is notable because its lineage is prop ...

'' appeared in the same region and by the Early Pleistocene (1 million YBP) ''Canis latrans'' (the coyote) was in existence. They proposed that the progression from ''Eucyon davisi'' to ''C lepophagus'' to the coyote was linear evolution. Additionally, ''C. edwardii'', ''C. latrans'' and ''C. aureus'' form together a small clade and because ''C. edwardii'' appeared earliest spanning the mid-Blancan (late Pliocene) to the close of the Irvingtonian (late Pleistocene) it is proposed as the ancestor. Nowak and Tedford also believed that it was possible for ''C. lupus'' to have been derived from a Miocene or Pliocene canid line that preceded and was separate from ''C. lepophagus''. Based on morphology from China, the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Middle Pleistocene The Chibanian, widely known by its previous designation of Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. Th ...

and is a wolf-like form larger than any ''Canis'' at that time. At the end of the most recent glacial retreat during the past 30,000 years, warming melted the glacial barriers across northern Canada allowing arctic mammals to extend their range into mid-latitude North America, including elk, caribou, bison, and the grey wolf. In Eurasia during the Middle Pleistocene, ''C. falconeri'' gave rise to the hypercarnivore genus ''

'', which then gave rise to genus ''

Cuon The dhole (''Cuon alpinus''; ) is a canid native to Central, South, East and Southeast Asia. Other English names for the species include Asian wild dog, Asiatic wild dog, Indian wild dog, whistling dog, red dog, red wolf, and mountain wolf. ...

'' (the dhole) and genus '' Lycaon'' (the African hunting dog). Just before the appearance of ''C. dirus'', North America was invaded by genus ''Xenocyon'' that was as large as ''C. dirus'' and more hypercarnivorous. The fossil record shows them as rare and it is assumed that they could not compete with the newly derived ''C. dirus''.

''Canis antonii''

The large wolf ''C. antonii'' from late Pliocene to early Pleistocene China was assessed as being a variation within ''C. chihliensis'', and the large wolf ''C. falconeri'' occurred abruptly in Europe in the Early Pleistocene, perhaps representing a westward extension of ''C. antonii''.

''Canis lupus''

The earliest ''Canis lupus'' specimen was a fossil tooth discovered at

Old Crow, Yukon Old Crow is a community in the Canadian territory of Yukon. Located in a periglacial environment, the community is situated on the Porcupine River in the far northern part of the territory. Old Crow is the only Yukon community that cannot be re ...

, Canada. The specimen was found in sediment dated 1 million YBP, however the geological attribution of this sediment is questioned. Slightly younger specimens were discovered at Cripple Creek Sump, Fairbanks, Alaska, in strata dated 810,000 YBP. Both discoveries point to an origin of these wolves in east Beringia during the

. In France, the subspecies ''C. l. lunellensis'' Bonifay, 1971 discovered at Lunel-Viel,

Hérault Hérault (; oc, Erau, ) is a department of the region of Occitania, Southern France. Named after the Hérault River, its prefecture is Montpellier. It had a population of 1,175,623 in 2019.Santenay, Côte-d'Or Santenay () is a commune in the Côte-d'Or department in eastern France. Lying at the southern end of the Côte de Beaune, it is an appellation of Burgundy wine. Population Sights Santenay is the location of the chateau of Philip the Bold (1 ...

dated to 200,000 YBP, and '' C. lupus maximus'' Boudadi-Maligne, 2012 from Jaurens cave,

Nespouls Nespouls is a commune in the Corrèze department in central France. Population See also *Communes of the Corrèze department The following is a list of the 279 communes of the Corrèze department of France France (), officia ...

Corrèze Corrèze (; oc, Corresa) is a department in France, named after the river Corrèze which runs through it. Although its prefecture is Tulle, its most populated city is Brive-la-Gaillarde. Corrèze is located in the Nouvelle-Aquitaine region ...

dated 31,000 YBP, show a progressive increase in size and are proposed to be chrono-subspecies. In Italy, the earliest ''Canis lupus'' specimens were found at La Polledrara di Cecanibbio, 20 km north-west of Rome in strata dated 340,000–320,000 YBP. In 2017, a study found that the dimensions of the upper and lower carnassial teeth of the early Holocene Italian wolf are close to those of ''C. l. maximus''. Fluctuations in the size of ''C. lupus'' carnassial teeth correlate with the spread of megafauna. The Italian wolf underwent a reduction in body size with the loss of the red deer in Italy during the Renaissance. The proposed lineage is: In 2020, a new species of wolf ''C. borjgali'' was discovered in

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

. This wolf is proposed to be the next evolutionary step after ''C. mosbachensis'' and an ancestor of the ''C. lupus'' lineage.

''Canis c.f. familiaris'' - Paleolithic dog

There are a number of recently discovered specimens which are proposed as being Paleolithic dogs, however their taxonomy is debated. These have been found in either Europe or Siberia and date 40,000-17,000 YBP. They include

Hohle Fels The ''Hohle Fels'' () (also ''Hohlefels'', ''Hohler Fels'', German for "hollow rock") is a cave in the Swabian Jura of Germany that has yielded a number of important archaeological finds dating from the Upper Paleolithic. Artifacts found in the ...

in Germany,

Goyet Caves The Goyet Caves (french: Grottes de Goyet) are a series of connected caves located in Wallonia in a limestone cliff about 15 m (50 ft) above the river Samson near the village of Mozet in the Gesves municipality of the Namur province, Belgium. The ...

in Belgium, Predmosti in the Czech Republic, and four sites in Russia: Razboinichya Cave, Kostyonki-8, Ulakhan Sular, and Eliseevichi 1. Paw-prints from

Chauvet Cave The Chauvet-Pont-d'Arc Cave (french: Grotte Chauvet-Pont d'Arc, ) in the Ardèche department of southeastern France is a cave that contains some of the best-preserved figurative cave paintings in the world, as well as other evidence of Upper Pale ...

in France dated 26,000 YBP are suggested as being those of a dog, however these have been challenged as being left by a wolf. Paleolithic dogs were directly associated with human hunting camps in Europe over 30,000 (YBP) and it is proposed that they were domesticated. They are also proposed to be either a proto-dog and the ancestor of the domestic dog or a type of wolf unknown to science.

''Canis familiaris'' (domestic dog)

In 2002, a study was undertaken into the fossil skulls of two large canids that had been found buried within meters of the doorway of what was once a mammoth-bone hut at the Eliseevichi-I

Upper Paleolithic The Upper Paleolithic (or Upper Palaeolithic) is the third and last subdivision of the Paleolithic or Old Stone Age. Very broadly, it dates to between 50,000 and 12,000 years ago (the beginning of the Holocene), according to some theories coin ...

site in the Bryansk Region on the Russian Plain, and using an accepted morphologically based definition of domestication declared them to be "Ice Age dogs". The carbon dating gave a calendar-year age estimate that ranged between 16,945–13,905 YBP. In 2013, a study looked at one of these skulls and its mitochondrial DNA sequence was identified as ''Canis familiaris''. In 2015, a zooarchaeologist stated that "In terms of phenotypes, dogs and wolves are fundamentally different animals." In 1986, a study of skull morphology found that the domestic dog is morphologically distinct from all other canids except the wolf-like canids. "The difference in size and proportion between some breeds are as great as those between any wild genera, but all dogs are clearly members of the same species." In 2010, a study of dog skull shape compared to extant

carnivorans Carnivora is a monophyletic order of placental mammals consisting of the most recent common ancestor of all cat-like and dog-like animals, and all descendants of that ancestor. Members of this group are formally referred to as carnivorans, ...

proposed that "The greatest shape distances between dog breeds clearly surpass the maximum divergence between species in the Carnivora. Moreover, domestic dogs occupy a range of novel shapes outside the domain of wild carnivorans."

Comparison with modern wolves

The domestic dog compared to the modern wolf shows the greatest variation in the size and shape of the skull (Evans 1979) that range from 7 to 28 cm in length (McGreevy 2004). Wolves are

dolichocephalic Dolichocephaly (derived from the Ancient Greek δολιχός 'long' and κεφαλή 'head') is a condition where the head is longer than would be expected, relative to its width. In humans, scaphocephaly is a form of dolichocephaly. Dolichoce ...

(long skulled) but not as extreme as some breeds of such as greyhounds and Russian wolfhounds (McGreevy 2004). Canine

brachycephaly Brachycephaly (derived from the Ancient Greek '' βραχύς'', 'short' and '' κεφαλή'', 'head') is the shape of a skull shorter than typical for its species. It is perceived as a desirable trait in some domesticated dog and cat breeds, ...

(short-skulledness) is found only in domestic dogs and is related to

paedomorphosis Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compare ...

(Goodwin 1997). Puppies are born with short snouts, with the longer skull of dolichocephalic dogs emerging in later development (Coppinger 1995). Other differences in head shape between brachycephalic and dolichocephalic dogs include changes in the craniofacial angle (angle between the basilar axis and

hard palate The hard palate is a thin horizontal bony plate made up of two bones of the facial skeleton, located in the roof of the mouth. The bones are the palatine process of the maxilla and the horizontal plate of palatine bone. The hard palate spans t ...

) (Regodón 1993), morphology of the

temporomandibular joint In anatomy, the temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below; it is from these bones that it ...

(Dickie 2001), and radiographic anatomy of the

cribriform plate In mammalian anatomy, the cribriform plate (Latin for lit. ''sieve-shaped''), horizontal lamina or lamina cribrosa is part of the ethmoid bone. It is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities. It supp ...

(Schwarz 2000). Nowak indicated that orbital angle of the eye socket is an important characteristic defining the difference between the dog and the wolf, with the wolf having the lower angle. Nowak compared the orbital angles of four North American

canines Canine may refer to: Zoology and anatomy * a dog-like Canid animal in the subfamily Caninae ** ''Canis'', a genus including dogs, wolves, coyotes, and jackals ** Dog, the domestic dog * Canine tooth, in mammalian oral anatomy People with the surn ...

(including the Indian dog) and produced the following values in degrees: coyote-42.8, wolf-42.8, dog-52.9 dire wolf-53.1. The orbital angle of the eye socket was clearly larger in the dog than in the coyote and the wolf; why it was almost the same as that of the dire wolf was not commented on. Many authors have concluded that compared to the adult extant wolf, the adult domestic dog has a relatively reduced rostrum (front part of the skull), an elevated

frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, pa ...

, a wider

palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly separ ...

, a broader cranium, and smaller teeth (Hildebrand1954; Clutton-Brock, Corbet & Hills 1976; Olsen 1985; Wayne 1986; Hemmer 1990; Morey 1990). Other authors have disagreed and have stated that these traits can overlap and vary within the two (Crockford 1999; Harrison 1973). Wolf cubs have similar relative skull proportions as adult dogs and this was proposed as evidence that the domestic dog is a neotenic wolf. This was proposed to be due to either human selection for juvenile appearance or due to a

pleiotropic Pleiotropy (from Greek , 'more', and , 'way') occurs when one gene influences two or more seemingly unrelated phenotypic traits. Such a gene that exhibits multiple phenotypic expression is called a pleiotropic gene. Mutation in a pleiotropic ge ...

effect as a result of selection for juvenile behavior (Clutton-Brock 1977; Belyaev 1979; Wayne 1986; Coppinger and Schneider 1995). Wayne (1986) concluded that his dog samples did not have significant relative shortening of the rostrum compared to wolves, calling this identification feature into question. A 2004 study that used 310 wolf skulls and over 700 dog skulls representing 100 breeds concluded that the evolution of dog skulls can generally not be described by heterochronic processes such as neoteny although some pedomorphic dog breeds have skulls that resemble the skulls of juvenile wolves.Drake, Abby Grace, "Evolution and development of the skull morphology of canids: An investigation of morphological integration and heterochrony" (January 1, 2004). Doctoral Dissertations Available from Proquest. Paper AAI3136721
link
/ref> "Dogs are not paedomorphic wolves." Compared to the wolf, dog dentition is relatively less robust (Olsen 1985; Hemmer 1990), which is proposed to be due to the relaxation of natural selection when wolves became commensal scavengers, or to artificial selection (Olsen 1985; Clutton-Brock 1995). However, Kieser and Groeneveld (1992) compared the mandibulo-dental measurements of jackals (''C. adustus, C. mesomelas'') and Cape foxes (''Vulpes chama'') to equivalent-sized dogs and found that the canines of these other canids tended to be slightly smaller and their second molars larger compared to dogs, otherwise the proportions were essentially the same in all species. They concluded that "...the teeth of canids appear to have evolved in concert with one another and relatively independently of differences in dimorphism, size or functional demands". This calls into question the assumption that dog teeth are relatively small due to recent selection, suggesting that dog dentition is plesiomorphic from an ancestor that was smaller than the wolf. The reduced body size of the early dog compared to a wolf is thought due to niche selection (Olsen 1985; Morey 1992; Coppinger & Coppinger 2001). Morey (1992:199) states that "Results...are consistent with a hypothesis that early domestic dogs are evolutionary paedomorphs, products of strong selection for ontogenetically channeled size reduction and alterations of reproductive timing associated with the new domestic way of life." However, in an domestication experiment the domesticated foxes remained the same size as unselected foxes (Trutt 1999:167). Wayne (1986) concluded that the dog is closer in skull morphology to ''C. latrans, C. aureus, C. adustus, C. mesomelas, Cuon alpinus'' and ''Lycaon pictus'' than to the wolf. Dahr (1942) concluded that the shape of the dog brain case is closer to that of the coyote than to that of the wolf. Manwell and Baker (1983) reviewed Dahr's work with the addition of dental data for canids and concluded that the dog ancestor was probably within the range of 13.6–20.5 kg, which is smaller than the range 27–54 kg for extant wolves (Mech 1970) and is comparable with the Dingo. The auditory bulla of the dog is relatively smaller and flatter than that of the wolf (Harrison 1973; Clutton-Brock, Corbet & Hill 1976; Nowak 1979; Olsen 1985; Wayne 1986), which is proposed to be due to relaxed selection under domestication as the dog no longer required the acute hearing of the wolf. However, bulla shape has been shown to facilitate increased sensitivity to specific frequencies but shape and size may not be correlated with acuity (Ewer 1973). Therefore, the observed difference could be that the dog bulla has retained its ancestral shape. The ventral edge of the dog's horizontal

ramus of the mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

has a convex curve that does not exist in the wolf (Olsen 1985; Clutton-Brock 1995), and no discussion of this difference could be found in the literature. However, Biknevicius and Van Valkenburgh (1997) noticed that the horizontal ramus of bone-processing predators is thicker dorso-ventrally at the point caudal to the site of bone processing. This thickening may have been a function for niche adaptation by the dog's ancestor. A description of the superficial brain morphology of jackals (''C. mesomelas, C. aureus''), coyotes (''C. latrans''), wolves (''C. lupus, C. rufus''), and dogs indicated that the cerebellum of the dog closely approximates that of the coyote, which is closely aligned with the jackals, and that the wolves show numerous brain traits distinct from the other species (Atkins and Dillon 1971). Wolves also have serological and biochemical traits distinct from dogs (Leone and Wiens 1956; Lauer, Kuyt & Baker 1969). The tails of domestic dogs tend to curl upwards, which is not found in other canid. Dogs possess a domed forehead, which is easy to see in a profile view with a bulge above the

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...

(the bony socket) of the eye. The

temporalis muscle In anatomy, the temporalis muscle, also known as the temporal muscle, is one of the muscles of mastication (chewing). It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomati ...

that closes the jaws is more robust in wolves. Compared with equally sized wolves, dogs possess 20% smaller skulls, and compared with equally weighted wolves dogs possess 20% smaller brains. The tympanic bullae are large, convex, and almost spherical in wolves, while the bullae of dogs are smaller, compressed, and slightly crumpled. Dogs have a distinctive "stop" between the forehead and nose. Domestic dogs are distinguishable from wolves by starch gel electrophoresis of red blood cell acid phosphatase. During the Last Glacial Maximum, there was greater wolf genetic diversity than there is today, and within the Pleistocene grey wolf population the variations between local environments would have encouraged a range of wolf ecotypes that were genetically, morphologically and ecologically distinct from one another. One author has proposed that the most likely explanation for the different morphological characteristics of the dog compared to the wolf is that the dog's ancestor was adapted to a different niche than the wolf.

Genetic record

DNA sequences

The mitochondria within each

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...

contain many copies of a small circular DNA genome and in mammals it is 16,000–18,000 base pairs in length. A cell contains hundreds or thousands of mitochondria and therefore the genes contained within those mitochondria are more abundant than the genes that occur in the nucleus of the cell. The abundance of mitochondrial DNA (mDNA) is useful for the genetic analysis of ancient remains where the DNA has degraded. Mitochondrial

DNA sequences A nucleic acid sequence is a succession of bases signified by a series of a set of five different letters that indicate the order of nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. By convention, sequences are us ...

have a higher

mutation rate In genetics, the mutation rate is the frequency of new mutations in a single gene or organism over time. Mutation rates are not constant and are not limited to a single type of mutation; there are many different types of mutations. Mutation rates ...

than the mutation rate of nuclear genes and for mammals this rate is 5–10 times faster. The mitochondrial protein-coding genes evolve much faster and are powerful markers for inferring evolution history at category levels such as families, genera, and species. However, they have evolved at a faster rate than other DNA markers and there is a timing difference in its molecular clock that needs to be validated against other sources. The taxonomic status of uncertain species is better resolved through using

nuclear DNA Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. I ...

from the nucleus of the cell, which is more suitable for analyzing the recent history. In most cases, mDNA is inherited from the maternal ancestor. Therefore,

phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

of mDNA sequences within species provides a history of maternal lineages that can be represented as a phylogenetic tree.

The mutations that are different in these 4

sequences In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is called t ...

have been numbered and bolded. These mutations can then be used to build a phylogenetic tree for the four canids. In this example, the dog and grey wolf differ by two substitutions (highlighted in red), and each of them differs from the coyote by four substitutions. 1234567 Golden JackalA-G-C-T-G-T-C-GA-T-TC-CA Coyote A-G-C-T-A-T-C-GA-A-TC-GA Wolf T-G-C-T-A-T-G-GA-T-TC-CT Dog T-G-G-T-A-T-G-GA-T-TC-CA

The mDNA sequences of the dog and wolf differ by only 0–12 substitutions within 261 base-pairs, whereas dogs always differed from coyotes and jackals by at least 20 substitutions. This finding implies that the dog derived from the wolf and that there has been repeated back-crossing, or that the dog may have descended from a now extinct species of canid whose closest living relative is the modern wolf.

Marker issue

Different DNA studies may give conflicting results because of the specimens selected, the technology used, and the assumptions made by the researchers. Any one from a panel of

genetic marker A genetic marker is a gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species. It can be described as a variation (which may arise due to mutation or alteration in the genomic loci) that can be ...

s can be chosen for use in a study. The techniques used to extract,

locate Locate may refer to: * Locate (finance) * Locator software, in computing * Locate (Unix), Linux command to find files * Locate di Triulzi, an Italian commune of Lombardy * Locate Varesino Locate Varesino (Comasco: ) is a '' comune'' (municipal ...

and

compare Comparison or comparing is the act of evaluating two or more things by determining the relevant, comparable characteristics of each thing, and then determining which characteristics of each are similar to the other, which are different, and t ...

genetic sequences can be applied using advances in technology, which allows researchers to observe longer lengths of base pairs that provide more data to give better

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

resolution.

Phylogenetic trees A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

compiled using different

genetic markers A genetic marker is a gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species. It can be described as a variation (which may arise due to mutation or alteration in the genomic loci) that can ...

have given conflicting results on the relationship between the wolf, dog and coyote. One study based on

SNPs In genetics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently larg ...

(a single

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA replication, DNA or viral repl ...

), and another based on

nuclear gene A nuclear gene is a gene whose physical DNA nucleotide sequence is located in the cell nucleus of a eukaryote. The term is used to distinguish nuclear genes from genes found in mitochondria or chloroplasts. The vast majority of genes in eukary ...

sequences (taken from the cell nucleus), showed dogs clustering with coyotes and separate from wolves. Another study based on SNPS showed wolves clustering with coyotes and separate from dogs. Other studies based on a number of markers show the more widely accepted result of wolves clustering with dogs separate from coyotes. These results demonstrate that caution is needed when interpreting the results provided by genetic markers.

Timing issue

There are two key assumptions that are made for dating the divergence time for species: the

generation time In population biology and demography, generation time is the average time between two consecutive generations in the lineages of a population. In human populations, generation time typically ranges from 22 to 33 years. Historians sometimes use this ...

and the genetic

per generation. The time between generations for wolves is assumed to be three years based on the extant grey wolf, and two years for the dog based on the extant dog. One recent major study assumed a generation time of 2 years for the dog for as far back as 10,000 years ago, and then assumed a generation time of 3 years (the same as the wolf) before that to calculate a proposed divergence time between the two. In 2017, the wolf research scientist L. David Mech queried why evolutionary biologists were calculating the approximate time of the dog diverging from the wolf through using a wolf generation time of three years when published works using large data sets demonstrate a figure of 4.2–4.7 years. They were encouraged to recalculate their divergence dates accordingly. DNA studies are conducted but with "the mutation rate as the dominant source of uncertainty." In 2005, Lindblad-Toh sequenced the first draft genome of the extant dog, and calculated a proposed mutation rate of 1x10⁻⁸ mutations per generation. In 2015, Skoglund was able to sequence the first draft genome of the 35,000 YBP Taimyr wolf and used its radio-carbon date to validate a proposed genetic mutation rate of 0.4x10⁻⁸ mutations per generation. The difference is a timing factor of 2.5, however another study stated that because only one Pleistocene wolf specimen has so far been sequenced, then the result should be treated with caution, with that study then providing both estimates to calculate the proposed divergence times between the wolf and dog. However, in 2016 the mutation rate of the 4,800 YBP Newgrange dog matched that of the Taimyr wolf.

Wolf-like canids

The wolf-like canids (the canid subfamily

) are a group of large carnivores that are genetically closely related because their

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

s number 78. The group includes genus ''Canis'', ''Cuon'' and ''Lycaon''. The members are the

dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Do ...

''(C. familiaris)'',

(''C. lupus''), coyote (''C. latrans''),

golden jackal The golden jackal (''Canis aureus''), also called common jackal, is a wolf-like canid that is native to Southeast Europe, Southwest Asia, South Asia, and regions of Southeast Asia. The golden jackal's coat varies in color from a pale creamy ...

(''C. aureus''),

Ethiopian wolf The Ethiopian wolf (''Canis simensis''), also called the Simien jackal and Simien fox, is a canine native to the Ethiopian Highlands. In southeastern Ethiopia it is also known as the horse jackal. It is similar to the coyote in size and build, ...

(''C. simensis''), black-backed jackal (''Lupulella mesomelas''),

side-striped jackal The side-striped jackal (''Lupulella adusta)'' is a canine native to central and southern Africa. Unlike the smaller and related black-backed jackal (''Lupulella mesomelas''), which dwells in open plains, the side-striped jackal primarily dwell ...

(''Lupulella adusta''),

dhole The dhole (''Cuon alpinus''; ) is a canid native to Central, South, East and Southeast Asia. Other English names for the species include Asian wild dog, Asiatic wild dog, Indian wild dog, whistling dog, red dog, red wolf, and mountain wolf. It ...

(''Cuon alpinus''), and

African wild dog The African wild dog (''Lycaon pictus''), also called the painted dog or Cape hunting dog, is a wild canine which is a native species to sub-Saharan Africa. It is the largest wild canine in Africa, and the only extant member of the genus '' Lyca ...

(''Lycaon pictus''). Newly proposed members include the red wolf (''Canis rufus''),

eastern wolf The eastern wolf (''Canis lycaon'' or ''Canis lupus lycaon'' or ''Canis rufus lycaon'') also known as the timber wolf, Algonquin wolf or eastern timber wolf, is a canine of debated taxonomy native to the Great Lakes region and southeastern Canad ...

(''Canis lycaon''), and

African golden wolf The African wolf (''Canis lupaster'') or golden wolf, formerly known as the African golden jackal, is a canine native to North Africa, West Africa, the Sahel, northern East Africa, and the Horn of Africa. It is listed as least concern on the IUC ...

(''C. anthus''). As they possess 78 chromosomes, all members of the genus ''Canis'' (coyotes, wolves, jackals) are karyologically indistinguishable from each other, and from the dhole and the African hunting dog. The members of ''Canis'' can potentially

interbreed In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in ...

and there is evidence that the Ethiopian wolf has hybridized with dogs. According to zoologist Reginald Pocock, a dhole interbred with a golden jackal. The African hunting dog is large, highly mobile, known to disperse over large distances and are rare throughout much of their geographical range, making opportunities for hybridization difficult. A study of the maternal mitochondrial DNA of the black-backed jackal could find no evidence of

genotypes The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...

from the most likely mates – the side-striped jackal nor the golden jackal – indicating that male black-backed jackals had not bred with these. A search of the scientific literature could not find evidence of hybridization for the rare side-striped jackal. A DNA sequence alignment for the wolf-like canids gave a phylogenetic tree with the grey wolf and dog being the most closely related, followed by a close affiliation with the coyote, golden jackal and Ethiopian wolf, and the dog can hybridize in the wild with these three species. Next closest to this group are the dhole and African wild dog that both have unique meat-slicing teeth, suggesting that this adaptation was later lost by the other members. The two African jackals are shown as the most basal members of this clade, which means that this tree is indicating an African origin for the clade. The tree illustrates the

genotype–phenotype distinction The genotype–phenotype distinction is drawn in genetics. "Genotype" is an organism's full hereditary information. "Phenotype" is an organism's actual observed properties, such as morphology, development, or behavior. This distinction is fundam ...

, where a genotype is an organism's full hereditary information and a

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological pr ...

is an organism's actual observed properties, such as

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...

, or behavior. By phenotype, the dhole (genus ''Cuon'') and the African hunting dog (genus ''Lycaon'') are not classified as members of the genus ''Canis'', but by genotype they are closer to dogs, wolves and coyotes than are the two genus ''Canis'' jackals – the Side-striped jackal (''C. adustus'') and the Black-backed jackal (''C. mesomelas''). In 2015, a study of mitochondrial genome sequences and nuclear genome sequences of African and Eurasian canids indicated that extant wolf-like canids had colonized Africa from Eurasia at least 5 times throughout the Pliocene and Pleistocene, which is consistent with fossil evidence suggesting that much of the African canid diversity resulted from the immigration of Eurasian ancestors, likely coincident with Plio-Pleistocene climatic oscillations between arid and humid conditions. The phylogenetic tree for the wolf-like canids may give conflicting positions for the black-backed jackal and the side-striped jackal relative to the genus ''Canis'' members depending on whether the genetic markers were based on mitochondrial DNA or nuclear DNA. The explanation proposed for this mito-nuclear discord is that mitochondrial DNA introgression occurred from an ancient ancestor of genus ''Canis'' into the lineage that led to the black-backed jackal around 6.2–5.2 million years ago. Phylogenetic tree of the extant wolf-like canids, with the pink shading representing the species ''Canis lupus''.

Admixture with an extinct unknown canid

In 2018,

whole genome sequencing Whole genome sequencing (WGS), also known as full genome sequencing, complete genome sequencing, or entire genome sequencing, is the process of determining the entirety, or nearly the entirety, of the DNA sequence of an organism's genome at a ...

was used to compare members of genus ''Canis'', along with the dhole (''Cuon alpinus'') and the African hunting dog (''Lycaon pictus''). There is evidence of gene flow between African golden wolves,

golden jackals The golden jackal (''Canis aureus''), also called common jackal, is a wolf-like canid that is native to Southeast Europe, Southwest Asia, South Asia, and regions of Southeast Asia. The golden jackal's coat varies in color from a pale creamy y ...

, and grey wolves. The study suggests that the African golden wolf is a descendant of a genetically admixed canid of 72% grey

wolf The wolf (''Canis lupus''; : wolves), 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, and gray wolves, as popularly un ...

and 28%

ancestry, and that the Ethiopian wolf once had a wider range in Africa. One African golden wolf from the Egyptian

Sinai Peninsula The Sinai Peninsula, or simply Sinai (now usually ) (, , cop, Ⲥⲓⲛⲁ), is a peninsula in Egypt, and the only part of the country located in Asia. It is between the Mediterranean Sea to the north and the Red Sea to the south, and is ...

showed high admixture with the Middle Eastern grey wolves and dogs, highlighting the role of the land bridge between the African and Eurasian continents in canid evolution. There is evidence of gene flow between golden jackals and Middle Eastern wolves, less so with European and Asian wolves, and least with North American wolves. The study proposes that the golden jackal ancestry found in North American wolves may have occurred before the divergence of the Eurasian and North American grey wolves. The study indicates that the common ancestor of the coyote and grey wolf has genetically admixed with a

ghost population A ghost population is a population that has been inferred through using statistical techniques. Population studies In 2004, it was proposed that maximum likelihood or Bayesian approaches that estimate the migration rates and population sizes using ...

of an extinct unidentified canid. The canid is genetically close to the

and has evolved after the divergence of the African hunting dog from the other canid species. The basal position of the coyote compared to the wolf is proposed to be due to the coyote retaining more of the mitochondrial genome of this unknown canid. A genomic study on the wolves of China included museum specimens of wolves from southern China that were collected between 1963 and 1988. The wolves in the study formed 3 clades: north Asian wolves that included those from northern China and eastern Russia, Himalayan wolves from the Tibetan Plateau, and a unique population from southern China. One specimen located as far southeast as

Jiangxi Jiangxi (; ; formerly romanized as Kiangsi or Chianghsi) is a landlocked province in the east of the People's Republic of China. Its major cities include Nanchang and Jiujiang. Spanning from the banks of the Yangtze river in the north int ...

province shows evidence of being admixed between Tibetan-related wolves and other wolves in China. One specimen from

Zhejiang Zhejiang ( or , ; , Chinese postal romanization, also romanized as Chekiang) is an East China, eastern, coastal Provinces of China, province of the People's Republic of China. Its capital and largest city is Hangzhou, and other notable citie ...

province in eastern China shared gene flow with the wolves from southern China, however its genome was 12-14 percent admixed with a canid that may be the dhole or an unknown canid that predates the genetic divergence of the dhole. The wolf population from southern China is believed to be still existing in that region.

Out of Beringia

Grey wolves suffered a species-wide population bottleneck (reduction) approximately 25,000 YBP during the Last Glacial Maximum. This was followed by a single population of modern wolves expanding out of a Beringia refuge to repopulate the wolf's former range, replacing the remaining Late Pleistocene wolf populations across Eurasia and North America as they did so. This source population probably did not give rise to dogs, but admixed with dogs which allowed them to gain coat colour genes that are also related to immunity, and provided dogs with genes which allowed them to adapt to high-altitude environments (e.g. Tibet). This suggests that the genetic divergence of European and East Asian dogs could be based on admixture with different sub-populations of wolves. There is little genetic information available on the ancient wolves that existed prior to the bottleneck. However, studies show that one or more of these ancient populations is more directly ancestral to dogs than are modern wolves, and conceivably these were more prone to domestication by the first humans to invade Eurasia. As of 2020, the oldest known intact wolf remains belongs to a mummified pup dated 56,000 YBP that was recovered from the permafrost along a small tributary of Last Chance Creek near

Dawson City Dawson City, officially the City of Dawson, is a town in the Canadian territory of Yukon. It is inseparably linked to the Klondike Gold Rush (1896–99). Its population was 1,577 as of the 2021 census, making it the second-largest town in Yuko ...

, Yukon, Canada. A DNA analysis showed that it belonged to the Beringian wolf clade, that the

of this clade dates to 86,700–67,500 YBP, and that this clade was basal to all other wolves except for the Himalayan wolf.

Into America and Japan

In 2016, a study built on the work of another major study and analyzed the sequences of 12 genes that are located on the heavy strand of the mitochondrial genome of extinct and modern ''C. lupus''. The study excluded the sequences of the divergent

Himalayan wolf The Himalayan wolf (''Canis lupus chanco'') is a canine of debated taxonomy. It is distinguished by its genetic markers, with mitochondrial DNA indicating that it is genetically basal to the Holarctic gray wolf, genetically the same wolf as t ...

and the Indian grey wolf. The ancient specimens were

radiocarbon dated Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was dev ...

and stratagraphically dated, and together with the sequences generated a time-based phylogenetic tree. From the tree, the study was able to infer the most recent common ancestor for all other ''C. lupus'' specimens – modern and extinct – was 80,000 YBP and this date concurred with the earlier study. The study could find no evidence of a population bottleneck for wolves until a few thousand years ago. The phylogenetic tree showed the polyphyly of American wolves, the Mexican wolf was divergent from other North American wolves, and these other North American wolves formed two closely related clades. A scenario consistent with the phylogenetic, ice sheet and sea-level data was that during the Ice Age when sea levels were at their lowest, there was a single wave of wolf colonization into North America starting with the opening of the

Bering land bridge Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72 degrees north latitude in the Chukchi Sea; and on the south by the tip of ...

70,000 YBP and closing during the

Late Glacial Maximum The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Ice sheets covered much of Northern North America, Northern Eu ...

of the Yukon corridor that ran through the division between the

Laurentide Ice Sheet The Laurentide Ice Sheet was a massive sheet of ice that covered millions of square miles, including most of Canada and a large portion of the Northern United States, multiple times during the Quaternary glacial epochs, from 2.58 million year ...

and the Cordilleran Ice Sheet 23,000 YBP. Mexican wolves were part of the single wave and either diverged from the other wolves before entering North America or once in North America due to the change in its environment. As wolves had been in the fossil record of North America but modern wolves could trace their ancestry back only 80,000 years, the wolf haplotypes that were already in North America were replaced by these invaders, either through competitive displacement or through admixture. The replacement in North America of a basal population of wolves by a more recent one supported the findings of earlier studies. There possibly existed a panmictic wolf population with gene flow spanning Eurasia and North America until the closing of the ice sheets. Once the sheets closed, the southern wolves were isolated and north of the sheets only the

Beringian wolf The Beringian wolf is an extinct population of wolf (''Canis lupus'') that lived during the Ice Age. It inhabited what is now modern-day Alaska, Yukon, and northern British Columbia. Some of these wolves survived well into the Holocene. The ...

existed. The land bridge became inundated by the sea 10,000 YBP, the sheets receded 12,000–6,000 YBP, the Beringian wolf went extinct and the southern wolves expanded to recolonize the rest of North America. All North American wolves are descended from those that were once isolated south of the ice sheets. However, much of their diversity was later lost during the twentieth century. Studies using mitochondrial DNA have indicated that the wolves of coastal south-east Alaska are genetically distinct from inland grey wolves, reflecting a pattern also observed in other taxa. They show a phylogenetic relationship with extirpated wolves from the south (Oklahoma), indicating that these wolves are the last remains of a once widespread group that has been largely extirpated during the last century, and that the wolves of northern North America had originally expanded from southern refuges below the

Wisconsin glaciation The Wisconsin Glacial Episode, also called the Wisconsin glaciation, was the most recent glacial period of the North American ice sheet complex. This advance included the Cordilleran Ice Sheet, which nucleated in the northern North American Cord ...

after the ice had melted at the end of the Last Glacial Maximum. A whole-genome DNA study indicated that all North American wolves were monophyletic and therefore are the descendants of a common ancestor. During the same period, the Soya Strait between

Hokkaido is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel. The lar ...

and Sakhalin Island was dry for 75,000 years and it was proposed that the extinct Ezo wolf (''C. l. hattai'') arrived on Hokkaido from Sakhalin. However, the sequences indicated that it arrived in Hokkaido less than 10,000 YBP. The Ezo wolf was closely related to one of the North American clades, but different from the more southerly

Japanese wolf The Japanese wolf ( ja, ニホンオオカミ（日本狼）, ja, script=Latn, label= Hepburn, Nihon ōkami, or , below]; ''Canis lupus hodophilax''), also known as the Honshū wolf, is an extinct subspecies of the gray wolf that was once endem ...

(''C. l. hodophilax'') that was basal to modern wolves. The Japanese wolf inhabited Kyushu, Shikoku, and Honshu islands but not Hokkaido Island. This indicates that its ancestor may have migrated from the Asian continent through the Korean Peninsula into Japan. The past sea levels of the

Korean Strait The Korea Strait is a sea passage in East Asia between Korea and Japan, connecting the East China Sea, the Yellow Sea and the Sea of Japan in the northwest Pacific Ocean. The strait is split by the Tsushima Island into the Western Channel and t ...

together with the timing of the Japanese wolf sequences indicated that it arrived to the southern islands less than 20,000 YBP. In 2020, a genomic study found that the Japanese wolf was the last of the Siberian Pleistocene wolves, which were thought to have gone extinct at the end of the Late Pleistocene (11,700 years ago). Some of these had survived into the 20th Century and had admixed with Japanese dogs. The dog was a very successful invader of North America and had established a widespread

ecological niche In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (for ...

by the Early–Middle Holocene. There was no overlap in niche between the dog and the wolf in comparison to the dog and other North American canids. By the Late Holocene, the dog's niche area was less in size than researchers had expected to find, indicating that it was limited by

biotic factors An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

. These regions include the northeast and northwest of the United States that correlate with the greatest densities of early human occupation, indicating that the dog had "defected" from the wolf niche to the human niche and explains why the dog's niche area was not as large as expected. The separation between dog and wolf may reflect the rapid rate in which domestication occurred, including the possibility of a second domestication event occurring in North America. Packs of wolves and hunter-gatherers hunt similar prey in a similar way within a similar group social structure that may have facilitated wolf domestication. The wolf was exterminated in the southern part of their historic geographical range in North America by the middle of the 20th century. An mDNA study of 34 wolf remains from North America dated between 1856 and 1915 found their genetic diversity to be twice that of modern wolves in these regions, and two thirds of the haplotypes identified were unique. These results indicate that a historic population of several hundred thousand wolves once existed in Mexico and the western US.

Divergence with the coyote

In 1993, a study proposed that the wolves of North America display skull traits more similar towards the coyote than those wolves from Eurasia. In 2016, a whole-genome DNA study proposed, based on the assumptions made, that all of the North American wolves and coyotes diverged from a common ancestor less than 6,000–117,000 years ago. The study also indicated that all North American wolves have a significant amount of coyote ancestry and all coyotes some degree of wolf ancestry, and that the red wolf and

are highly admixed with different proportions of grey wolf and coyote ancestry. However, the test that was used cannot differentiate between anceint and recent hybridization. One test indicated a wolf/coyote divergence time of 51,000 years before present that matched other studies indicating that the extant wolf came into being around this time. Another test indicated that the red wolf diverged from the coyote between 55,000–117,000 years before present and the Great Lakes region wolf 32,000 years before present. But a 2000 study on the haplotypes of North American canids showed that the divergences between coyotes, grey wolves, red wolves, and algonquin (eastern) wolves happened much earlier. This study showed that there was a 3.2 % divergence between the eastern Canadian wolf and coyote gene sequences, and a 2.3 % sequence divergence between the red wolf and coyote haplotypes. However, the divergence was a much greater 8.0% between gray wolf (C. lupus) mtDNA and eastern/red wolf haplotypes, and 10.0% between gray wolf and coyote haplotypes. The sequence difference observed between eastern Canadian wolf sequences and coyote sequences is consistent with a separation of 150 000 – 300 000 years, using a divergence rate of 1–2% per 100 000 years. Additionally, conflicting with the recent divergent hypothesis, the fossil record that indicates a coyote-like specimen dated to 1 million years before present. The modern grey wolf expanded out of Beringia 25,000 years ago. The modern coyote appeared around 10,000 years ago, and most likely descended from the

Pleistocene coyote The Pleistocene coyote (''Canis latrans orcutti''), also known as the Ice Age coyote, is an extinct subspecies of coyote that lived in western North America during the Late Pleistocene era. Most remains of the subspecies were found in southern Ca ...

. The most genetically basal coyote mDNA clade pre-dates the Last Glacial Maximum and is a haplotype that can only be found in the Eastern wolf. This implies that the large, wolf-like

was the ancestor of the

Eastern wolf The eastern wolf (''Canis lycaon'' or ''Canis lupus lycaon'' or ''Canis rufus lycaon'') also known as the timber wolf, Algonquin wolf or eastern timber wolf, is a canine of debated taxonomy native to the Great Lakes region and southeastern Canad ...

and Red wolf, which diverged from each other later in time.

Domestic dog

The domestic dog (''Canis lupus familiaris'') is the most widely abundant large carnivore. Over the past million years, numerous wolf-like forms existed but their turnover has been high, and modern wolves are not the lineal ancestors of dogs. Although research had suggested that dogs and wolves were genetically very close relatives, later

strongly supported the hypothesis that dogs and wolves are reciprocally monophylic

taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

that form two sister

clades A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

. This suggests that none of the modern wolf populations are related to the wolves that were first domesticated and the wolf ancestor of dogs is therefore presumed extinct. Recent mitochondrial DNA analyses of ancient and modern grey wolf specimens supports a pattern of population reduction and turnover. An alternate proposal is that during the ecological upheavals of the Late Pleistocene all of the remaining members of a dwindling lineage joined humans. In 2016, a study investigated for the first time the population subdivisions, demography, and the relationships of grey wolves based on their whole-genome sequences. The study indicated that the dog was a divergent subspecies of the grey wolf and was derived from a now-extinct

of Late Pleistocene wolves, and the dog and the dingo are not separate species. The genome-wide phylogenetic tree indicated a genetic divergence between New World and Old World wolves, which was then followed by a divergence between the dog and Old World wolves 27,000YBP – 29,000 YBP. The dog forms a sister taxon with Eurasian grey wolves but not North American wolves. The dog had considerable pre-ancestry after its divergence from the Old World wolves before it separated into distinct lineages that are nearly as distinct from one another as they are from wolves. The study suggested that previous datings based on the divergence between wolves and coyotes of one million years ago using fossils of what appeared to be coyote-like specimens may not reflect the ancestry of the modern forms. The study indicated that the

Mexican wolf The Mexican wolf (''Canis lupus baileyi''), also known as the lobo,; nah, Cuetlāchcoyōtl is a subspecies of gray wolf native to southeastern Arizona and southern New Mexico in the United States, and northern Mexico; it also previously rang ...

was also a divergent form of grey wolf, suggesting that may have been part of an early invasion into North America. The Tibetan wolf was found to be the most highly divergent of the Old World wolves, had suffered a historical population bottleneck and had only recently recolonized the Tibetan Plateau. Glaciation may have caused its habitat loss, genetic isolation then local adaption. The study indicated that there has been extensive

genetic admixture Genetic admixture occurs when previously diverged or isolated genetic lineages mix.⅝ Admixture results in the introduction of new genetic lineages into a population. Examples Climatic cycles facilitate genetic admixture in cold periods and gene ...

between domestic dogs and wolves, with up to 25% of the genome of Old World wolves showing signs of dog ancestry, possibly as the result of gene flow from dogs into wolves that were ancestral to all modern wolves. There was evidence of significant gene flow between the European wolves plus the Israeli wolf with the

basenji The Basenji ( /bəˈsɛndʒi/) is a breed of hunting dog. It was bred from stock that originated in central Africa. The Fédération Cynologique Internationale places the breed in the Spitz and primitive types. The Basenji produces an unusual y ...

and boxer, which suggests admixture between the lineages ancestral to these breeds and wolf populations. For the lowland Asian wolves: the Central Russian and East Russian wolves and all of the lowland Chinese wolves had significant gene flow with the Chinese indigenous dogs, the

Tibetan Mastiff The Tibetan Mastiff ( bo, འདོགས་ཁྱི, THL: , Wylie: ) * Nepali: * Mongolian: * Hindi/ Garhwali/ Kumaoni: * Kashmiri: * Ladakhi: * Dzongkha: is a large size Tibetan dog breed. Its double coat is medium to long, subject t ...

and the dingo. For the highland Asian wolves: The Tibetan wolves did not show significant admixture with dogs; however, the

Qinghai Qinghai (; alternately romanized as Tsinghai, Ch'inghai), also known as Kokonor, is a landlocked province in the northwest of the People's Republic of China. It is the fourth largest province of China by area and has the third smallest po ...

wolves had gene flow with the dingo and one of them had gene flow with the Chinese dogs. The New World wolves did not show any gene flow with the boxer, dingo or Chinese indigenous dogs but there was indication of gene flow between the Mexican wolf and the African basenji. All species within the genus ''Canis'', the wolf-like canids, are phylogenetically closely related with 78

s and can potentially

. There was indication of gene flow into the

from the population ancestral to all wolves and dogs (11.3%–13.6%) and much lower rates (up to 2.8%) from extant wolf populations. The data indicated that all wolves shared similar population trajectories, followed by population decline that coincided with the expansion of modern humans worldwide and their technology for capturing large game. Late Pleistocene carnivores would have been social living in large prides, clans and packs in order to hunt the larger game available at that time, and these larger groups would have been more conspicuous targets for human persecutors. Large dogs accompanying the humans may have accelerated the rate of decline of carnivores that competed for game, therefore humans expanded across Eurasia, encountered wolves, domesticated some and possibly caused the decline of others. The study concluded that admixture had confounded the ability to make inferences about the place of dog domestication. Past studies based on SNPs, genome-wide similarities with Chinese wolves, and lower

linkage disequilibrium In population genetics, linkage disequilibrium (LD) is the non-random association of alleles at different loci in a given population. Loci are said to be in linkage disequilibrium when the frequency of association of their different alleles is h ...

might reflect regional admixture between dogs with wolves and gene flow between dog populations, with divergent dog breeds possibly maintaining more wolf ancestry in their genome. The study proposed that analysis of ancient DNA might be a better approach. In the same year, a study found that there were only 11 fixed genes that showed variation between wolves and dogs. These genes are thought to affect tameness and emotional processing ability. Another study provided a listing of all of the grey wolf and dog mDNA haplotypes combined in the one phylogenetic tree. In 2018, a study compared the sequences of 61,000

Single-nucleotide polymorphisms In genetics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently larg ...

( mutations) taken from across the genome of grey wolves. The study indicated that there exists individual wolves of dog/wolf ancestry in most of the wolf populations of Eurasia but less so in North America. The hybridization has been occurring across different time scales and was not a recent event. Low-level hybridization did not reduce the wolf distinctiveness.

Dingo

The dingo (''Canis familiaris dingo'') refers to the dog found in Australia. The dingo is a divergent subspecies of the grey wolf and is not a separate species, and is considered genetically to be a basal member of the domestic dog clade. The genetic evidence indicates that the dingo originated from East Asian domestic dogs and was introduced through the South-East Asian archipelago into Australia, with a common ancestry between the Australian dingo and the

New Guinea Singing Dog The New Guinea singing dog or New Guinea Highland dog is an ancient ( basal) lineage of dog found in the New Guinea Highlands, on the island of New Guinea. Once considered to be a separate species in its own right, under the name ''Canis hallst ...

''Canis variabilis''

In 2015, a study looked at the mitochondrial control region sequences of 13 ancient canid remains and one modern wolf from five sites across Arctic north-east Siberia. The fourteen canids revealed nine mitochondrial haplotypes, three of which were on record and the others not reported before. The phylogentic tree generated from the sequences showed that four of the Siberian canids dated 28,000 YBP and one ''Canis c.f. variabilis'' dated 360,000 YBP were highly divergent. The haplotype designated as S805 (28,000 YBP) from the

Yana River The Yana ( rus, Я́на, p=ˈjanə; sah, Дьааҥы, ''Caañı'') is a river in Sakha in Russia, located between the Lena to the west and the Indigirka to the east. Course It is long, and its drainage basin covers . Including its longes ...

was one mutation away from another haplotype S902 (8,000 YBP) that represents Clade A of the modern wolf and domestic dog lineages. Closely related to this haplotype was one that was found in the recently extinct

. Several ancient haplotypes were oriented around S805, including ''Canis c.f. variabilis'' (360,000 YBP), Belgium (36,000 YBP – the "Goyet dog"), Belgium (30,000 YBP), and Konsteki, Russia (22,000 YBP). Given the position of the S805 haplotype on the phylogenetic tree, it may potentially represent a direct link from the progenitor (including ''Canis c.f. variabilis'') to the domestic dog and modern wolf lineages. The grey wolf is thought to be ancestral to the domestic dog, however its relationship to ''C. variabilis'', and the genetic contribution of ''C. variabilis'' to the dog, is the subject of debate. The

Zhokhov Island Zhokhov Island ( rus, Остров Жохова, r=Ostrov Zhokhova; sah, Жохов Aрыыта, translit=Joqov Arııta) is an island in the East Siberian Sea, situated 128 km north east of Novaya Sibir Island, the easternmost of the New S ...

(8,700 YBP) and Aachim (1,700 YBP) canid haplotypes fell within the domestic dog clade, cluster with S805, and also share their haplotypes with – or are one mutation away from – the

Tibetan wolf The Himalayan wolf (''Canis lupus chanco'') is a canine of debated taxonomy. It is distinguished by its genetic markers, with mitochondrial DNA indicating that it is genetically basal to the Holarctic gray wolf, genetically the same wolf as the ...

(''C. l. filchneri'') and the recently extinct Japanese wolf (''C. l. hodophilax''). This may indicate that these canids retained the genetic signature of admixture with regional wolf populations. Another haplotype designated as S504 (47,000 YBP) from

Duvanny Yar Qobustan or Gobustan may refer to: * Gobustan District, Azerbaijan * Qobustan (town), administrative center of Gobustan District, Azerbaijan * Qobustan, Baku, a settlement and municipality in Azerbaijan ** Gobustan National Park, World Heritage Site ...

appeared on the phylogenetic tree as not being connected to wolves (both ancient and modern) yet ancestral to dogs, and may represent a genetic source for regional dogs. The authors concluded that the structure of the modern dog gene pool was contributed to from ancient Siberian wolves and possibly from ''Canis c.f. variabilis''.

Rise to dominant predator

In 2015, a study looked at the paleoecology of large carnivores across the

Mammoth steppe During the Last Glacial Maximum, the mammoth steppe, also known as steppe-tundra, was the Earth's most extensive biome. It spanned from Spain eastward across Eurasia to Canada and from the arctic islands southward to China. The mammoth steppe ...

during the Late Pleistocene by using stable isotope analysis of their fossil collagen to reconstruct their diets. Based on testing in Belgium, around 40,000 YBP the Cave hyenas preyed on mammoth, woolly rhinoceros, horses and reindeer, with cave lions taking reindeer and young

cave bear The cave bear (''Ursus spelaeus'') is a prehistoric species of bear that lived in Europe and Asia during the Pleistocene and became extinct about 24,000 years ago during the Last Glacial Maximum. Both the word "cave" and the scientific name ' ...

s. Wolves appear to have been out-competed by cave hyenas and had their diet restricted to chamois, giant deer and red deer. However, after the Last Glacial Maximum around 14,000 YBP, wolves had access to all prey species, the cave lion was restricted to reindeer, and the cave hyena had gone extinct. The data suggests that the extinction of the cave hyena allowed the wolf to become the dominant predator rather than the cave lion, just before the cave lion's extinction. Another study indicated that the wolf thrived compared to the cave hyena when there was greater snow cover.

Wolf population differences

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

. 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. The archaeological and paleontological records show their continuous presence for at least the last 300,000 years. This continuous wolf presence contrasts with genomic studies, which suggest that all modern wolves and dogs descend from a common ancestral wolf population that existed as recently as 20,000 years ago. These studies indicate that a population bottleneck was followed by a rapid radiation from an ancestral population at a time during, or just after, the Last Glacial Maximum. This implies that the original wolf populations were out-competed by a new type of wolf which replaced them. However, the geographic origin of this radiation is not known. Apart from domestication, humans have harmed the wolf by restricting its habitat through persecution. This has caused a dramatic decrease in its population size over the last two centuries. The shrinking of its habitats that overlap with those of close-relatives such as dogs and coyotes have led to numerous occurrences of hybridization. These events, in addition to recent turnovers (extinctions and repopulations by other geneotypes), has made the unravelling of the

phylogeographic Phylogeography is the study of the historical processes that may be responsible for the past to present geographic distributions of genealogical lineages. This is accomplished by considering the geographic distribution of individuals in light of ge ...

history of the wolf difficult.

Ecotypes

ecotype In evolutionary ecology, an ecotype,Greek: ''οίκος'' = home and ''τύπος'' = type, coined by Göte Turesson in 1922 sometimes called ecospecies, describes a genetically distinct geographic variety, population, or race within a specie ...

is a variant in which the

phenotypic In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...

differences are too few or too subtle to warrant being classified as a subspecies. These can occur in the same geographic region where distinct habitats such as meadow, forest, swamp, and sand dunes provide ecological niches. Where similar ecological conditions occur in widely separated places it is possible for a similar ecotype to occur. This is different from a subspecies, which may exist across a number of different habitats. In animals, ecotypes can be regarded as micro-subspecies that owe their differing characteristics to the effects of a very local environment. Ecotypes have no

taxonomic rank In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in an ancestral or hereditary hierarchy. A common system consists of species, genus, family, order, class, phylum, kingdom, domain. While ...

. Grey wolves have a wide, natural distribution across the

that includes many different habitats, which can vary from the high arctic to dense forests, open steppe and deserts. The genetic differences between different populations of grey wolves is tightly linked to the type of habitat in which they live. Differences in genetic markers among the Scandinavian wolf population has arisen in only just over a decade due to their small population size, which indicates that these differences are not dependent on a long time spent in isolation and that larger population patterns can evolve in just a few thousand years. These differences can also include fur color and density, and body size. The differences can also include behavior, as coastal wolves eat fish and tundra wolves migrate. These differences have been observed between two wolf populations that are living in close proximity. It has been shown that mountain wolves do not interbreed with nearby coastal wolves, and the Alps of France and Switzerland have been repopulated with wolves from the mountains of nearby Italy and from the far away mountains of Croatia rather than from the nearer lowlands, which indicates that distance is not the driving force in differences between the two ecomorphs. In 2013, a genetic study found that the wolf population in Europe was divided along a north–south axis and formed five major clusters. Three clusters were identified occupying southern and central Europe in Italy, the Carpathians, and the Dinaric-Balkans. Another two clusters were identified occupying north-central Europe and the Ukrainian steppe. The Italian wolf consisted of an isolated population with low genetic diversity. Wolves from Croatia, Bulgaria, and Greece formed the Dinaric-Balkans cluster. Wolves from Finland, Latvia, Belarus, Poland and Russia formed the north-central Europe cluster with wolves from the Carpathians cluster a mixture of wolves from the north-central cluster and the Dinaric-Balkans cluster. The wolves from the Carpathians were more similar to the wolves from the Ukrainian Steppe than they were to wolves from north-central Europe. These clusters may have been the result of expansion from glacial refugia, an adaptation to local environments, and landscape fragmentation and the killing of wolves in some areas by humans. In 2016, two studies compared the sequences of 42,000 single nucleotide polymorphisms in North American grey wolves and found that they formed six ecotypes. These six wolf ecotypes were named West Forest, Boreal Forest, Arctic, High Arctic, Baffin, and British Columbia. The studies found that precipitation and mean diurnal temperature range were the most influential variables on sequence variation. These findings were in accord with previous findings that precipitation influenced morphology, and that vegetation and habitat type influenced wolf differences. One of these studies found that the variation in 11 key genes affected wolf vision, sense of smell, hearing, coat color, metabolism, and immunity. The study identified 1,040 genes that are potentially under selection due to habitat variation, and therefore that there was evidence of local adaption of the wolf ecotypes at a molecular level. Most notable was the positive selection of genes that influence vision, coat color, metabolism and immunity in the Arctic and High Arctic ecotypes, and that the British Columbia ecotype also has a unique set of adaptions. The local adaptation of a wolf ecotype most likely reflects a wolf's preference to remain in the type of habitat that it was born into. Ecological factors including habitat type, climate, prey specialization and predatory competition will greatly influence grey wolf genetic population structure and cranio-dental plasticity. During the Last Glacial Maximum, there was greater wolf genetic diversity than there is today, and within the Pleistocene grey wolf population the variations between local environments would have encouraged a range of wolf ecotypes that were genetically, morphologically and ecologically distinct from one another.

Pleistocene wolves

During the Last Glacial Maximum 20,000 YBP, the Pleistocene steppe stretched across northern and central Eurasia and through Beringia into North America. The Pleistocene wolves of Beringia, and perhaps those across the steppe, were adapted to this habitat. Their tooth and skull morphology indicates that they specialized in preying on now-extinct

Pleistocene megafauna Pleistocene megafauna is the set of large animals that lived on Earth during the Pleistocene epoch. Pleistocene megafauna became extinct during the Quaternary extinction event resulting in substantial changes to ecosystems globally. The role of ...

, and their tooth wear indicates that their behavior was different from modern wolves. This highlights the success of ''C. lupus'' as a species in adapting to different environmental conditions. This grey wolf ecomorph became extinct at the end of the glaciation, along with the horse and other species on which it depended, and was replaced by wolves from southern North America. This indicates that specialized wolf ecomorphs can become extinct when their environment changes even though the habitat may still support other wolves. Wolves went through a population bottleneck 20,000 YBP that coincides with the Last Glacial Maximum, which indicates that many wolf populations may have gone extinct at the same time as the Beringian wolves. There are a small number of ''Canis'' remains that have been found at Goyet Cave, Belgium (36,500 YBP) Razboinichya Cave, Russia (33,500 YBP) Kostenki 8, Russia (33,500–26,500 YBP) Predmosti, Czech Republic (31,000 YBP) and Eliseevichi 1, Russia (17,000 YBP). Based on cranial morphometric study of the characteristics thought to be associated with the domestication process, these have been proposed as early Paleolithic dogs. These characteristics of shortened rostrum, tooth crowding, and absence or rotation of premolars have been documented in both ancient and modern wolves. Rather than representing early dogs, these specimens may represent "a morphologically distinct local, now extinct, population of wolves".

Notes

References

Works

* {{evolution Pleistocene carnivorans Pleistocene extinctions Prehistoric canines Pleistocene first appearances