Mexican wolf

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Mexican wolf
Mexican Wolf 2 yfb-edit 1.jpg
Captive Mexican wolf at Sevilleta National Wildlife Refuge, New Mexico
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Genus: Canis
C. l. baileyi
Trinomial name
Canis lupus baileyi
(Nelson & Goldman, 1929)
Canis lupus baileyi range.png
C. l. baileyi range

The Mexican wolf (Canis lupus baileyi), also known as the lobo, [lower-alpha 1] is a subspecies of gray wolf once native to southeastern Arizona, southern New Mexico, western Texas and northern Mexico. It is the smallest of North America's gray wolves, [2] and is similar to C. l. nubilus , though it is distinguished by its smaller, narrower skull and its darker pelt, which is yellowish-gray and heavily clouded with black over the back and tail. [3] Its ancestors were likely the first gray wolves to enter North America after the extinction of the Beringian wolf, as indicated by its southern range and basal physical and genetic characteristics. [4]


Though once held in high regard in Pre-Columbian Mexico, [5] it is the most endangered gray wolf in North America, having been extirpated in the wild during the mid-1900s through a combination of hunting, trapping, poisoning and digging pups from dens. After being listed under the Endangered Species Act in 1976, the United States and Mexico collaborated to capture all lobos remaining in the wild. This extreme measure prevented the lobos' extinction. Five wild Mexican wolves (four males and one pregnant female) were captured alive in Mexico from 1977 to 1980 and used to start a captive breeding program. From this program, captive-bred Mexican wolves were released into recovery areas in Arizona and New Mexico beginning in 1998 in order to assist the animals' recolonization of their former historical range. [6]

As of 2017, there are 143 Mexican wolves living wild and 240 in captive breeding programs. [7]


The Mexican wolf was first described as a distinct subspecies in 1929 by Edward Nelson and Edward Goldman on account of its small size, narrow skull and dark pelt. [8] This wolf is recognized as a subspecies of Canis lupus in the taxonomic authority Mammal Species of the World (2005). [9] In 2019, a literature review of previous studies was undertaken by the National Academies of Sciences, Engineering, and Medicine. The position of the National Academies is that the historic population of Mexican wolf represents a distinct evolutionary lineage of gray wolf, and that modern Mexican wolves are their direct descendants. It is a valid taxonomic subspecies classified as Canis lupus baileyi. [10]


Gray wolves (Canis lupus) migrated from Eurasia into North America 70,000–23,000 years ago [11] [12] and gave rise to at least two morphologically and genetically distinct groups. One group is represented by the extinct Beringian wolf [11] [13] and the other by the modern populations. [11] One author proposes that the Mexican wolf's ancestors were likely the first gray wolves to cross the Bering Land Bridge into North America during the Late Pleistocene after the extinction of the Beringian wolf, [13] colonizing most of the continent until pushed southwards by the newly arrived ancestors of C. l. nubilus . [4]

A haplotype is a group of genes found in an organism that are inherited together from one of their parents. [14] [15] Mitochondrial DNA (mDNA) passes along the maternal line and can date back thousands of years. [16] A 2005 study compared the mitochondrial DNA sequences of modern wolves with those from thirty-four specimens dated between 1856 and 1915. The historic population was found to possess twice the genetic diversity of modern wolves, [17] [18] which suggests that the mDNA diversity of the wolves eradicated from the western US was more than twice that of the modern population. Some haplotypes possessed by the Mexican wolf, the extinct Great Plains wolf, and the extinct Southern Rocky Mountain wolf were found to form a unique "southern clade". All North American wolves group together with those from Eurasia, except for the southern clade which form a group exclusive to North America. The wide distribution area of the southern clade indicates that gene flow was extensive across the recognized limits of its subspecies. [18]

In 2016, a study of mitochondrial DNA sequences of both modern and ancient wolves generated a phylogenetic tree which indicated that the two most basal North American haplotypes included the Mexican wolf and the Vancouver Island wolf. [19]

In 2018, a study looked at the limb morphology of modern and fossil North American wolves. The major limb bones of the dire wolf, Beringian wolf, and most modern North American gray wolves can be clearly distinguished from one another. Late Pleistocene wolves on both sides of the Laurentide Ice SheetCordilleran Ice Sheet possessed shorter legs when compared with most modern wolves. The Late Pleistocene wolves from the Natural Trap Cave, Wyoming and Rancho La Brea, southern California were similar in limb morphology to the Beringian wolves of Alaska. Modern wolves in the Midwestern USA and northwestern North America possess longer legs that evolved during the Holocene, possibly driven by the loss of slower prey. However, shorter legs survived well into the Holocene after the extinction of much of the Pleistocene megafauna, including the Beringian wolf. Holocene wolves from Middle Butte Cave (dated less than 7,600 YBP) and Moonshiner Cave (dated over 3,000 YBP) in Bingham County, Idaho were similar to the Beringian wolves. The Mexican wolf and pre-1900 samples of the Great Plains wolf (Canis lupus nubilus) resembled the Late Pleistocene and Holocene fossil gray wolves due to their shorter legs. [11]

Hybridization with coyotes and red wolves

Skull Mexicanwolfskull.jpg

Unlike eastern wolves and red wolves, the gray wolf species rarely interbreeds with coyotes in the wild. Direct hybridizations between coyotes and gray wolves was never explicitly observed. Nevertheless, in a study that analyzed the molecular genetics of the coyotes as well as samples of historical red wolves and Mexican wolves from Texas, a few coyote genetic markers have been found in the historical samples of some isolated individual Mexican wolves. Likewise, gray wolf Y-chromosomes have also been found in a few individual male Texan coyotes. [20] This study suggested that although the Mexican gray wolf is generally less prone to hybridizations with coyotes compared to the red wolf, there may have been exceptional genetic exchanges with the Texan coyotes among a few individual gray wolves from historical remnants before the population was completely extirpated in Texas. However, the same study also countered that theory with an alternative possibility that it may have been the red wolves, who in turn also once overlapped with both species in the central Texas region, who were involved in circuiting the gene-flows between the coyotes and gray wolves much like how the eastern wolf is suspected to have bridged gene-flows between gray wolves and coyotes in the Great Lakes region since direct hybridizations between coyotes and gray wolves is considered rare.

In tests performed on a sample from a taxidermied carcass of what was initially labelled as a chupacabra, mitochondrial DNA analysis conducted by Texas State University professor Michael Forstner showed that it was a coyote. However, subsequent analysis by a veterinary genetics laboratory team at the University of California, Davis concluded that, based on the sex chromosomes, the male animal was a coyote–wolf hybrid sired by a male Mexican wolf. [21] [22] It has been suggested that the hybrid animal was afflicted with sarcoptic mange, which would explain its hairless and blueish appearance. [21]

A study in 2018 that analyzed wolf populations suspected to have had past interactions with domestic dogs found no evidence of significant dog admixture into the Mexican wolf. [23] Another study in the same year was published in the PLOS Genetics Journal which analyzed the population genomics of gray wolves and coyotes from all over North America. [24] This study detected the presences of coyote admixtures in various western gray wolf populations, all previously thought to be free of coyote-introgression, and found that the Mexican wolves carry 10% coyote admixture. The study's author also suggests that the admixture from coyotes may have also played a role in the basal phylogenetic placement of this subspecies.


Early accounts of the distribution of the Mexican wolf included southeastern Arizona, southwestern New Mexico, sometimes western Texas, USA and the Sierra Madre Occidental, Mexico. This past distribution is supported by ecological, morphological, and physiographic data. The areas described coincide with the distribution of the Madrean pine-oak woodlands, a habitat which supports Coues’ white-tailed deer (Odocoileus virginianus couesi) that is the Mexican wolf's main prey. In 2017, there are at least 143 Mexican wolves living wild in Mexico, Arizona, and New Mexico. There are 240 in captive breeding programs in the USA and Mexico. [7]


The Aztec god Xolotl, depicted here in the 15th century Codex Fejervary-Mayer, may have been based on the Mexican wolf rather than a dog as once believed. Xolotl 1.jpg
The Aztec god Xolotl, depicted here in the 15th century Codex Fejervary-Mayer, may have been based on the Mexican wolf rather than a dog as once believed.

The Mexican wolf was held in high regard in Pre-Columbian Mexico, where it was considered a symbol of war and the Sun. In the city of Teotihuacan, it was common practice to crossbreed Mexican wolves with dogs to produce temperamental, but loyal, animal guardians. Wolves were also sacrificed in religious rituals, which involved quartering the animals and keeping their heads as attire for priests and warriors. The remaining body parts were deposited in underground funerary chambers with a westerly orientation, which symbolized rebirth, the Sun, the underworld and the canid god Xolotl. [5] The earliest written record of the Mexican wolf comes from Francisco Javier Clavijero's Historia de México in 1780, where it is referred to as Cuetzlachcojotl, and is described as being of the same species as the coyote, but with a more wolf-like pelt and a thicker neck. [25]

Traditional Zuni wolf fetish. Zuni Wolf Fetish.jpg
Traditional Zuni wolf fetish.


There was a rapid reduction of Mexican wolf populations in the Southwestern United States from 1915-1920; by the mid-1920s, livestock losses to Mexican wolves became rare in areas where the costs once ranged in the millions of dollars. [26] Vernon Bailey, writing in the early 1930s, noted that the highest Mexican wolf densities occurred in the open grazing areas of the Gila National Forest, and that wolves were completely absent in the lower Sonora. He estimated that there were 103 Mexican wolves in New Mexico in 1917, though the number had been reduced to 45 a year later. By 1927, it had apparently become extinct in New Mexico. [3] Sporadic encounters with wolves entering Texas, New Mexico and Arizona via Mexico continued through to the 1950s, until they too were driven away through traps, poison and guns. The last wild wolves to be killed in Texas were a male shot on December 5, 1970 on Cathedral Mountain Ranch and another caught in a trap on the Joe Neal Brown Ranch on December 28. Wolves were still being reported in small numbers in Arizona in the early 1970s, while accounts of the last wolf to be killed in New Mexico are difficult to evaluate, as all the purported "last wolves" could not be confirmed as genuine wolves rather than other canid species. [26]

The Mexican wolf persisted longer in Mexico, as human settlement, ranching and predator removal came later than in the Southwestern United States. Wolf numbers began to rapidly decline during the 1930s-1940s, when Mexican ranchers began adopting the same wolf-control methods as their American counterparts, relying heavily on the indiscriminate usage of 1080. [26]

Conservation and recovery

A pair of Mexican wolves with pups at Sevilleta Wolf Management Facility in Socorro, New Mexico Coronadopack2.jpg
A pair of Mexican wolves with pups at Sevilleta Wolf Management Facility in Socorro, New Mexico

The Mexican wolf was listed as endangered under the U.S. Endangered Species Act in 1976, with the Mexican Wolf Recovery Team being formed three years later by the United States Fish and Wildlife Service. The Recovery Team composed the Mexican Wolf Recovery Plan, which called for the reestablishment of at least 100 wolves in their historic range through a captive breeding program. Between 1977 and 1980, four males and a pregnant female were captured in Durango and Chihuahua in Mexico to act as founders of a new "certified lineage". By 1999, with the addition of new lineages, the captive Mexican wolf population throughout the US and Mexico reached 178 individuals. These captive-bred animals were subsequently released into the Apache National Forest in eastern Arizona, and allowed to recolonize east-central Arizona and south-central New Mexico, areas which were collectively termed the Blue Range Wolf Recovery Area (BRWRA). The Recovery Plan called for the release of additional wolves in the White Sands Wolf Recovery Area in south-central New Mexico, should the goal of 100 wild wolves in the Blue Range area not be achieved. [6]

By late 2012, it was estimated that there were at least 75 wolves and four breeding pairs living in the recovery areas, with 27% of the population consisting of pups. Since 1998, 92 wolf deaths were recorded, with four occurring in 2012; these four were all due to illegal shootings. [27]

Releases have also been conducted in Mexico, and the first birth of a wild wolf litter in Mexico was reported in 2014. [28]

A study released by the U.S. Fish and Wildlife Service in February 2015 shows a minimum population of 109 wolves in 2014 in southwest New Mexico and southeast Arizona, a 31 percent increase from 2013. [29]

According to a survey done on the population of the Mexican wolf in Alpine, Arizona, the recovery of the species is being negatively impacted due to poaching. In an effort to fight the slowing recovery, GPS monitoring devices are being used to monitor the wolves. [30]

In 2016, 14 Mexican wolves were killed, making it the highest death count of any year since they were reintroduced into the wild in 1998. 2 of the deaths were caused by officials trying to collar the animals. The rest of the deaths remain under investigation. [31] [32]

As of July 2017, approximately 31 wild Mexican gray wolves inhabited Chihuahua and Sonora, Mexico, in the northern Sierra Madre Occidental. As of November 2017, 114 Mexican gray wolves were living in the wild in Arizona and New Mexico, distributed in 22 packs across the two states. [33]

In February 2018, five more wolves were released in Chihuahua, bringing the total wild population in Mexico (Sonora and Chihuahua) to thirty-seven wolves. [34] In 2018, six Mexican wolf pups from the Endangered Wolf Center were sent to dens in Arizona and New Mexico for their survival. [35]

In 2019, the U.S. Fish and Wildlife Services discovered that 52 of 90 wolf pups born earlier in 2018 had survived to adulthood. These new wolves brought the number of Mexican gray wolves in Arizona and New Mexico to 163, with 87 wolves in New Mexico and 76 in Arizona. [36]

Further reading

See also


  1. Spanish: Lobo mexicano; Nahuatl languages: Cuetlāchcoyōtl

Related Research Articles

Coyote Species of canine native to North America

The coyote is a species of canine native to North America. It is smaller than its close relative, the gray wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological niche as the golden jackal does in Eurasia, though it is larger and more predatory and is sometimes called the American jackal by zoologists. Other names for the species, largely historical, include prairie wolf and brush wolf.

Subspecies of <i>Canis lupus</i> List of subspecies of the grey wolf

There are 38 subspecies of Canis lupus listed in the taxonomic authority Mammal Species of the World. These subspecies were named over the past 250 years, and since their naming a number of them have gone extinct. The nominate subspecies is the Eurasian wolf Canis lupus lupus.

Red wolf subspecies of mammal

The red wolf is a canine native to the southeastern United States which has a reddish-tawny color to its fur. Morphologically it is intermediate between the coyote and gray wolf, and is very closely related to the eastern wolf of eastern Canada.

Wolf Species of mammal (canine)

The wolf, also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. It is the largest extant member of Canidae, males averaging 40 kg (88 lb) and females 37 kg (82 lb). On average, wolves measure 105–160 cm (41–63 in) in length and 80–85 cm (31–33 in) at shoulder height. The wolf is also distinguished from other Canis species by its less pointed ears and muzzle, as well as a shorter torso and a longer tail. The wolf is nonetheless related closely enough to smaller Canis species, such as the coyote and the golden jackal, to produce fertile hybrids with them. The banded fur of a wolf is usually mottled white, brown, gray, and black. Up to 38 subspecies of wolf have been recognized including the domestic dog.

<i>Canis</i> genus of mammals

Canis is a genus of the Canidae containing multiple extant species, such as wolves, dogs, coyotes and jackals. Species of this genus are distinguished by their moderate to large size, their massive, well-developed skulls and dentition, long legs, and comparatively short ears and tails.

Eastern wolf subspecies of mammal

The eastern wolf, also known as the timber wolf, Algonquin wolf or eastern timber wolf, is a type of wolf native to the Great Lakes region and southeastern Canada, considered to be either a unique subspecies of gray wolf or a separate species from the gray wolf. Many studies have found the eastern wolf to be the product of ancient and recent genetic admixture between the gray wolf and the coyote, while other studies have found some or all populations of the eastern wolf, as well as coyotes, originally separated from a common ancestor with the wolf over 1 million years ago and that these populations of the eastern wolf may be the same species as or a closely related species to the red wolf of the Southeastern United States. Regardless of its status, it is regarded as unique and therefore worthy of conservation with Canada citing the population in eastern Canada as being the eastern wolf population subject to protection.

Arctic wolf Subspecies of the gray wolf found in the Canadian arctic, Alaska and parts of Greenland

The Arctic wolf, also known as the white wolf or polar wolf, is a subspecies of grey wolf native to Canada's Queen Elizabeth Islands, from Melville Island to Ellesmere Island. It is a medium-sized subspecies, distinguished from the northwestern wolf by its smaller size, its whiter colouration, its narrower braincase, and larger carnassials. Since 1930, there has been a progressive reduction in size in Arctic wolf skulls, which is likely the result of wolf-dog hybridization.

Coywolf Hybrid mammal

Coywolf is an informal term for a canid hybrid descended from coyotes, eastern wolves and gray wolves. All members of the genus Canis are genetically closely related because their chromosomes number 78, therefore they can interbreed. One genetic study indicates that these two species genetically diverged relatively recently. Genomic studies indicate that nearly all North American gray wolf populations possess some degree of admixture with coyotes following a geographic cline, with the lowest levels occurring in Alaska, and the highest in Ontario and Quebec, as well as Atlantic Canada.

Canid hybrids are the result of interbreeding between different species of the canine (dog) family. They often occur in the wild, in particular between domestic or feral dogs and wild native canids.

Great Plains wolf subspecies of mammal

The Great Plains wolf, also known as the buffalo wolf or loafer, is an extinct subspecies of gray wolf with a distribution that once extended throughout the Great Plains from southern Manitoba and Saskatchewan southward to northern Texas. The subspecies was declared extinct in 1926. They were described as a large, light-colored wolf but with black and white varying between individual wolves, with some all white or all black. The Native Americans of North Dakota told of how only three of these wolves could bring down any sized bison.

Wolf reintroduction involves the reestablishment of a portion of gray wolves in areas where native wolves have been extirpated. Reintroduction is only considered where large tracts of suitable wilderness still exist and where certain prey species are abundant enough to support a predetermined wolf population.

Indian wolf The only grey wolf subspecies in the Gir National Park

The Indian wolf is a subspecies of grey wolf that ranges from Southwest Asia to the Indian Subcontinent. It is intermediate in size between the Tibetan and Arabian wolf, and lacks the former's luxuriant winter coat due to it living in warmer conditions. Two closely related haplotypes within this subspecies have been found basal to all other extant Canis lupus haplotypes apart from the older-lineage Himalayan wolf, and have been proposed as a separate species. The Indian wolf travels in smaller packs and is less vocal than other variants of the grey wolf, and has a reputation for being cunning.

Himalayan wolf Subspecies of mammal

The Himalayan wolf 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 grey wolf, genetically the same wolf as the Tibetan wolf, and has an association with the African golden wolf. There are no striking morphological differences between the wolves from the Himalayas and those from Tibet. The Himalayan wolf lineage can be found living in the Himalayas and the Tibetan Plateau predominated above 4,000 metres in elevation because they have adapted to a low oxygen environment, compared with other wolves that are found only at lower elevations.

History of wolves in Yellowstone

When Yellowstone National Park was created in 1872, gray wolf populations were already in decline in Montana, Wyoming and Idaho. The creation of the national park did not provide protection for wolves or other predators, and government predator control programs in the first decades of the 1900s essentially helped eliminate the gray wolf from Yellowstone. The last wolves were killed in Yellowstone in 1926. After that time, sporadic reports of wolves still occurred, but scientists confirmed that sustainable wolf populations had been extirpated and were absent from Yellowstone during the mid-1900s.

Mogollon mountain wolf extinct subspecies of mammal

The Mogollon mountain wolf is an extinct subspecies of gray wolf whose range once included southern and western Texas and northeastern Mexico. It is darker than its more northern cousins, and has a highly arched frontal bone.

Greenland wolf subspecies of mammal

The Greenland wolf is a subspecies of gray wolf that is native to Greenland. Historically it was heavily persecuted, but today it is fully protected and about 90% of the wolf's range falls within the boundaries of the Northeast Greenland National Park. A recent genomic study has shown that wolves of Ellesmere Island, Canada, likely should be included in the same subspecies, a view also supported by earlier morphological reviews. The entire population is very small, probably about 200 individuals but with significant uncertainty due to its very remote range.

Southern Rocky Mountain wolf Extinct subspecies of the gray wolf

The southern Rocky Mountain wolf is an extinct subspecies of gray wolf which was once distributed over southeastern Idaho, southwestern Wyoming, northeastern Nevada, Utah, western and central Colorado, northwestern Arizona, and northwestern New Mexico. It was a light-colored, medium-sized subspecies closely resembling the Great Plains wolf, though larger, with more blackish-buff hairs on the back. This wolf was extirpated by 1940. Wolves of the subspecies Canis lupus occidentalis have now been reestablished in Idaho and Wyoming.

Beringian wolf extinct type of wolf that lived during the Ice Age in Alaska, Yukon, and northern Wyoming

The Beringian wolf is an extinct type of wolf that lived during the Ice Age. It inhabited what is now modern-day Alaska, Yukon, and northern Wyoming. Some of these wolves survived well into the Holocene. The Beringian wolf is an ecomorph of the gray wolf and has been comprehensively studied using a range of scientific techniques, yielding new information on the prey species and feeding behavior of prehistoric wolves. It has been determined that these wolves are morphologically distinct from modern North American wolves and genetically basal to most modern and extinct wolves. The Beringian wolf has not been assigned a subspecies classification and its relationship with the extinct European cave wolf is not clear.

Evolution of the wolf overview about the evolution of the wolf

The evolution of the wolf occurred over a geologic time scale of at least 300 thousand years. The grey wolf Canis lupus is a highly adaptable species that is able to exist in a range of environments and which possesses a wide distribution across the Holarctic. Studies of modern grey wolves have identified distinct sub-populations that live in close proximity to each other. This variation in sub-populations is closely linked to differences in habitat – precipitation, temperature, vegetation, and prey specialization – which affect cranio-dental plasticity.


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