The Mexican wolf (''Canis lupus baileyi''), also known as the ''lobo mexicano'' (or, simply, ''lobo'') is a
subspecies of gray wolf (''C. lupus'') native to eastern and southeastern
Arizona
Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...
and western and southern
New Mexico
New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
(in the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
) and fragmented areas of
northern Mexico
Northern Mexico ( ), commonly referred as , is an informal term for the northern cultural and geographical area in Mexico. Depending on the source, it contains some or all of the states of Baja California, Baja California Sur, Chihuahua (state), ...
. Historically, the subspecies ranged from eastern Southern California south into Baja California, east through the Sonora and Chihuahua Deserts and into
West Texas
West Texas is a loosely defined region in the U.S. state of Texas, generally encompassing the desert climate, arid and semiarid climate, semiarid lands west of a line drawn between the cities of Wichita Falls, Texas, Wichita Falls, Abilene, Texa ...
.
Its ancestors were likely among 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.
Though once held in high regard in
Pre-Columbian Mexico
The pre-Columbian (or prehispanic) history of the territory now making up the country of Mexico is known through the work of archaeologists and epigraphers, and through the accounts of Spanish conquistadores, settlers and clergymen as well as ...
,
''Canis lupus baileyi'' became the most endangered gray wolf subspecies in North America, having been extirpated in the wild during the mid-1900s through a combination of hunting, trapping, poisoning and the removal of pups from dens, mainly out of fear, by livestock herders and ranch owners. After being listed officially under the
Endangered Species Act
The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...
in 1976, both the United States and Mexico collaborated to capture all lobos remaining in the wild. This extreme preventative measure would end up forestalling their imminent extinction; five wild Mexican wolves (four males and one pregnant female) were captured, alive, in Mexico between 1977 and 1980. Once settled in captive rescue centers, this group of wolves would prove vital in starting a captive breeding program. Thanks to these preemptive measures, captive-bred Mexican wolves were released into recovery areas in Arizona and New Mexico beginning in 1998 in an effort to recolonize the animals' historical range.
[Nie, M. A. (2003), ''Beyond Wolves: The Politics of Wolf Recovery and Management'', University of Minnesota Press, pp. 118–119, ]
As of 2025, there are at least 286 wild Mexican wolves in the US and 45 in Mexico, and 380 in captive breeding programs, up from the 11 individuals that were released in Arizona in 1998. These numbers represent a minimum as the survey only counts wolf sightings confirmed by Interagency Field Team staff.
Description
The Mexican wolf is the smallest of North America's gray wolf subspecies, weighing with an average height of and an average length of .
It is similar to the
Great Plains wolf (''C. l. nubilus''), albeit distinguishable by a smaller, narrower skull and darker, more variable
pelage
A fur is a soft, thick growth of hair that covers the skin of almost all mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an ...
.
[Bailey, V. (1932)]
Mammals of New Mexico
U.S. Department of Agriculture, Bureau of Biological Survey. North American Fauna No. 53. Washington, D.C. Pages 303–308.
Taxonomy
The Mexican wolf was first described as a distinct subspecies in 1929 by
Edward Nelson
Edward Nelson (May 4, 1932 – September 10, 2014) was an American mathematician. He was professor in the Mathematics Department at Princeton University. He was known for his work on mathematical physics and mathematical logic. In mathematical l ...
and
Edward Goldman on account of its small size, narrow skull and dark pelt.
[ This wolf is recognized as a subspecies of ''Canis lupus'' in the taxonomic authority '']Mammal Species of the World
''Mammal Species of the World: A Taxonomic and Geographic Reference'' is a standard reference work in mammalogy giving descriptions and Bibliographic database, bibliographic data for the known species of mammals. It is now in its third edition, ...
(2005)''.[ In 2019, a ]literature review
A literature review is an overview of previously published works on a particular topic. The term can refer to a full scholarly paper or a section of a scholarly work such as books or articles. Either way, a literature review provides the rese ...
of previous studies was undertaken by the National Academies of Sciences, Engineering, and Medicine
The National Academies of Sciences, Engineering, and Medicine (NASEM), also known as the National Academies, is a Congressional charter, congressionally chartered organization that serves as the collective scientific national academy of the Uni ...
. 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''. Genetic analyses have confirmed that the Mexican wolf (''Canis lupus baileyi'') is the most genetically distinct subspecies of gray wolf in North America, emphasizing the importance of targeted conservation efforts to preserve its unique genetic heritage.
Lineage
Gray wolves (''Canis lupus'') migrated from Eurasia into North America 70,000–23,000 years ago[ and gave rise to at least two morphologically and genetically distinct groups. One group is represented by the extinct Beringian wolf][ and the other by the modern populations.] One author proposes that the Mexican wolf's ancestors were likely the first gray wolves to cross 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° north latitude in the Chukchi Sea; and on the south by the tip of the ...
into North America during the Late Pleistocene
The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...
after the extinction of the Beringian wolf,[ colonizing most of the continent until pushed southwards by the newly arrived ancestors of the Great Plains wolf (''C. l. nubilus'').][
A ]haplotype
A haplotype (haploid genotype) is a group of alleles in an organism that are inherited together from a single parent.
Many organisms contain genetic material (DNA) which is inherited from two parents. Normally these organisms have their DNA orga ...
is a group of genes
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
found in an organism that are inherited together from one of their parents.[ ]Mitochondrial DNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...
(mDNA) passes along the maternal line and can date back thousands of years.[ A 2005 study compared the mitochondrial ]DNA sequences
A nucleic acid sequence is a succession of bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the ...
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
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It ranges widely, from the number of species to differences within species, and can be correlated to the span of survival for a species. It is d ...
of modern wolves,[ 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 Great Plains wolf, and the extinct Southern Rocky Mountain wolf were found to form a unique "southern ]clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
". 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.[
In 2016, a study of mitochondrial DNA sequences of both modern and ancient wolves generated a ]phylogenetic tree
A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In ...
which indicated that the two most basal North American haplotypes included the Mexican wolf and the Vancouver Island wolf.[
In 2018, a study looked at the limb morphology of modern and fossil North American wolves. The major limb bones of the ]dire wolf
The dire wolf (''Aenocyon dirus'' ) is an Extinction, extinct species of Caninae, canine which was native to the Americas during the Late Pleistocene and Early Holocene epochs (125,000–10,000 years ago). The species was named in 1858, four y ...
, 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 Sheet — Cordilleran 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 US and northwestern North America possess longer legs that evolved during the Holocene
The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...
, 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
The Late Pleistocene to the beginning of the Holocene saw the extinction of the majority of the world's megafauna, typically defined as animal species having body masses over , which resulted in a collapse in faunal density and diversity acro ...
, 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 resembled the Late Pleistocene and Holocene fossil gray wolves due to their shorter legs.
Ancestor
In 2021, a mitochondrial DNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...
analysis of North American wolf-like canines indicates that the extinct Late Pleistocene Beringian wolf was the ancestor of the southern wolf clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
, which includes the Mexican wolf and the Great Plains wolf. The Mexican wolf is the most basal of the gray wolves that live in North America today.[
]
Hybridization with coyotes and other wolves
Multiple recent studies using morphological (skull measurements) and genetic datasets have concluded that Mexican wolves hybridized in clinal fashion with other wolf subspecies where both met. The Mexican Wolf Recovery plan (2017, First Revision) currently plans to manage against such occurrence in the event that Northern Rockies and Mexican wolves come into contact to protect against a genetic swamp (i.e. genes of one group become dominant and thus result in loss of genes of another group). While the purity of Mexican wolf DNA composition is important for the time being, a natural, free-ranging wolf population on a continental scale would include hybridization between different subspecies to occur freely. Mexican wolves are under considerable threat from low genetic diversity and inbreeding because all wild Mexican wolves share on average the same amount of genes as full siblings do (all present day wild wolves are descendants of an original seven, called founders).
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. 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
The chupacabra or ''chupacabras'' (, literally 'goat-sucker', from , 'sucks', and , 'goats') is a legendary creature, or cryptid, in the folklore of parts of the Americas. The name comes from the animal's purported vampirism the chupacabra is ...
, 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.["Texas State University Researcher Helps Unravel Mystery of Texas 'Blue Dog' Claimed to be Chupacabra"]
. bionews-tx.com (2013-09-01) It has been suggested that the hybrid animal was afflicted with sarcoptic mange, which would explain its hairless and blueish appearance.
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.[ 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. 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.
]
Distribution
Early accounts of the distribution of the Mexican wolf included southeastern Arizona, southwestern New Mexico, and western Texas in the U.S., and the Sierra Madre Occidental
The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through northwestern and western Mexico, and along the Gulf of California. The Sierra Madre is part of the American C ...
in 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
The white-tailed deer (''Odocoileus virginianus''), also known Common name, commonly as the whitetail and the Virginia deer, is a medium-sized species of deer native to North America, North, Central America, Central and South America. It is the ...
(''Odocoileus virginianus couesi'') that were historically the Mexican wolf's main prey.
Today, following their reintroduction and conservation, Mexican wolves are widely distributed across over 40,000 km2 (9.88 million acres) of western New Mexico and eastern Arizona, largely coinciding with the Apache-Sitgreaves and Gila National Forest
The Gila National Forest is a United States national forest in New Mexico. Established in 1905, it now covers approximately , making it the sixth largest national forest in the continental United States. The Forest administration also manage ...
s and the surrounding areas. Under the current Mexican Wolf Recovery Plan, this area is categorized as predominantly Wolf Management Zone 1 (the former Blue Range Wolf Recovery Area). This plan designates the wolf experimental population area as all of New Mexico and Arizona, south of Interstate Highway 40. Wolves sometimes disperse outside of this area, though they are sometimes caught and returned to the management zones. In 2024, a breeding pair of wolves were released into Arizona's Peloncillo Mountains, which are in Wolf Management Zone 2. A small population of wolves have also been reintroduced to Sonora and Chihuahua, Mexico.
History
Indigenous culture
The Mexican wolf was held in high regard in Pre-Columbian Mexico
The pre-Columbian (or prehispanic) history of the territory now making up the country of Mexico is known through the work of archaeologists and epigraphers, and through the accounts of Spanish conquistadores, settlers and clergymen as well as ...
, where it was considered a symbol of war and the Sun
The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
. In the city of Teotihuacan
Teotihuacan (; Spanish language, Spanish: ''Teotihuacán'', ; ) is an ancient Mesoamerican city located in a sub-valley of the Valley of Mexico, which is located in the State of Mexico, northeast of modern-day Mexico City.
Teotihuacan is ...
, it was common practice to crossbreed Mexican wolves with dogs to produce temperamental, but loyal, wolfdog
A wolfdog is a canine produced by the mating of a domestic dog (''Canis familiaris'') with a gray wolf (''Canis lupus''), eastern wolf (''Canis lycaon''), red wolf (''Canis rufus''), or Ethiopian wolf (''Canis simensis'') to produce a ...
guardians. Wolves were also sacrificed in religious
Religion is a range of social- cultural systems, including designated behaviors and practices, morals, beliefs, worldviews, texts, sanctified places, prophecies, ethics, or organizations, that generally relate humanity to supernatural ...
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
In Aztec mythology, Xolotl () was a god of fire and lightning. He was commonly depicted as a dog-headed man and was a soul-guide for the dead. He was also god of twins, monsters, death, misfortune, sickness, and deformities. Xolotl is the canin ...
. 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.[Clavijero, Francisco Javier (1817) ]
The history of Mexico
', Volume 1, Thomas Dobson, p. 57
The Apache
The Apache ( ) are several Southern Athabaskan language-speaking peoples of the Southwestern United States, Southwest, the Southern Plains and Northern Mexico. They are linguistically related to the Navajo. They migrated from the Athabascan ho ...
call Mexican wolves "ba'cho" or "ma'cho." There is a "wolf song" that is passed down through oral tradition
Oral tradition, or oral lore, is a form of human communication in which knowledge, art, ideas and culture are received, preserved, and transmitted orally from one generation to another.Jan Vansina, Vansina, Jan: ''Oral Tradition as History'' (19 ...
in the tribe, which was historically used to summon the wolf's power before battle. Other prayers and rituals have traditionally invoked the power of the wolf and other beings before deer hunts. Other indigenous names for the Mexican wolf include "shee’e" ( Akimel O'odham/Pima) and "Ma’iitsoh" ( Diné/Navajo). The Hopi
The Hopi are Native Americans who primarily live in northeastern Arizona. The majority are enrolled in the Hopi Tribe of Arizona and live on the Hopi Reservation in northeastern Arizona; however, some Hopi people are enrolled in the Colorado ...
call the wolf kachina
A kachina (; Hopi language, Hopi: ''katsina'' , plural ''katsinim'' ) is a spirit being in the religious beliefs of the Pueblo people, Native Americans in the United States, Native American cultures located in the south-western part of the Unite ...
(spirit being) "Kweo." The Havasupai have many traditional stories about Mexican wolves.
Decline
There was a rapid reduction of Mexican wolf populations in the Southwestern United States
The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...
from 1915 to 1920; by the mid-1920s, livestock losses to Mexican wolves became rare in areas where the costs once ranged in the millions of dollars.[1982.]
Mexican wolf recovery plan
U.S. Fish and Wildlife Service, Albuquerque, New Mexico. 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
The Gila National Forest is a United States national forest in New Mexico. Established in 1905, it now covers approximately , making it the sixth largest national forest in the continental United States. The Forest administration also manage ...
, and that wolves were completely absent in the lower Sonora
Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...
. He estimated that there were 103 Mexican wolves in New Mexico
New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
in 1917, though the number had been reduced to 45 a year later. By 1927, it had apparently become extinct in New Mexico.[ 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.][
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.]
Conservation and recovery
The Mexican wolf was listed as endangered under the U.S. Endangered Species Act
The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...
in 1976, with the Mexican Wolf Recovery Team being formed three years later by the United States Fish and Wildlife Service
The United States Fish and Wildlife Service (USFWS or FWS) is a List of federal agencies in the United States, U.S. federal government agency within the United States Department of the Interior which oversees the management of fish, wildlife, ...
. 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
Durango, officially the Free and Sovereign State of Durango, is one of the 31 states which make up the Political divisions of Mexico, 32 Federal Entities of Mexico, situated in the northwest portion of the country. With a population of 1,832,650 ...
and Chihuahua in Mexico to act as founders of a new "certified lineage". Three lineages were brought into the United States: McBride, Ghost Ranch and Aragón. Due to the limited number of founders for each lineage, these wolves can potentially carry the risks of inbreeding. However, cross-lineaged wolves have less inbreeding coefficients and greater reproductive success than purebred lineages. By 1999, with the addition of new lineages, the captive Mexican wolf population throughout the US and Mexico reached 178 individuals. Beginning in 1998, 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 lack of livestock-free zones and tolerance for these captive wolves outside of their restoration area can be challenging for Mexican wolf conservation. 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.
On October 11, 2011, 5 wolves (2 males and 3 females) were released into Sonora
Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...
's Madrean Sky Islands in Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
. Since then, Mexico's National Commission of Natural Protected Areas (CONANP) has facilitated 19 wolf releases into the country.
Since 1998, 92 wolf deaths were recorded, with four occurring in 2012; these four were all due to illegal shootings.[2012]
Mexican Wolf Recovery Program: Progress Report #15
US Fish and Wildlife Service Releases have also been conducted in Mexico, and the first birth of a wild wolf litter in Mexico was reported in 2014. In 2015, a court ordered the U.S. Fish and Wildlife revise the management rules. 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; poaching accounted for 50% of all Mexican wolf mortalities from 2008 to 2019. In an effort to fight the slowing recovery, GPS monitoring devices are being used to monitor the wolves. 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. Two of the deaths were caused by officials trying to collar the animals. The rest of the deaths remain under investigation.
In July 2017, approximately 31 wild Mexican gray wolves inhabited Chihuahua and Sonora, Mexico, in the northern Sierra Madre Occidental. In February 2018, five more wolves were released in Chihuahua, bringing the total wild population in Mexico (Sonora and Chihuahua) to thirty-seven wolves. In 2018, six Mexican wolf pups from the Endangered Wolf Center were sent to dens in Arizona and New Mexico for their survival. The 2019 census found more than 30 wolves in Mexico.
Eight Mexican wolf cubs were born at the Desert Museum in Saltillo
Saltillo () is the capital and largest city of the northeastern Mexican state of Coahuila and is also the municipal seat of the municipality of the same name. Mexico City, Monterrey, and Saltillo are all connected by a major railroad and high ...
, Coahuila on July 1, 2020. In March 2021, a family of nine Mexican gray wolves (a breeding pair of wolves and their seven pups) were released into the wild of northern Mexico, bringing the total number of wolves in Mexico to around 40 wild individuals.
Captive-born wolves may be released as a well-bonded pack consisting of a breeding pair along with their pups. Captive-born pups, who are less than 14 days old, are also released by being placed with similarly aged pups to be raised as wild wolves. In 2021, 22 pups were placed into wild dens to be raised by surrogate packs under this method known as cross-fostering. This mitigates some of the potential inbreeding depression
Inbreeding depression is the reduced biological fitness caused by loss of genetic diversity as a consequence of inbreeding, the breeding of individuals closely related genetically. This loss of genetic diversity results from small population siz ...
issues by introducing more distantly related wolves from captivity. 2024 marked the 100th wolf pup to be cross-fostered.
In June 2021, a year-old male Mexican gray wolf named Anubis traveled out of the Mexican Wolf Recovery Area and settled in the Coconino National Forest
The Coconino National Forest is a 1.856-million acre (751,000 ha) United States National Forest located in northern Arizona in the vicinity of Flagstaff, with elevations ranging from 2,600 feet to the highest point in Arizona at 12,633 feet (H ...
in central Arizona. He was one of several Mexican gray wolves to have dispersed into the area over several years; the male individual may be the first permanent resident of Mexican gray wolves to settle in the Coconino National Forest. The U.S. Fish and Wildlife Service was ordered by the court to review the rule that caps the U.S. population at 325 wolves. In 2021, a male Mexican gray wolf was stopped from crossing from New Mexico into Mexico by a section of border wall. 2022 had the lowest number of mortalities (12 total) since 2017.
Current population
On March 9, 2022, two new breeding pairs of Mexican gray wolves were released into the wild in the state of Chihuahua in northern Mexico, bringing the total number of wild Mexican gray wolves in the country to around 35–45 individuals.
In March 2025, the wild Mexican wolf population of the United States totaled at least 286 individuals: 162 in New Mexico (37 packs and 16 breeding pairs) and 124 in Arizona (23 packs and 10 breeding pairs). At least 79 out of the known 164 pups born in 2024 survived until the year's end (48% survival rate). 39% of the U.S. Mexican wolf population is collared with GPS and radio collars. 2024 represented the 9th consecutive year of population growth, and an 11% increase compared to 2023.
The total captive Mexican wolf population is 380 individuals, across over 60 facilities.
Interagency Field Team
The wild Mexican wolf population in the United States is managed by the Interagency Field Team (IFT), whose collaborating participants include the US Fish and Wildlife Service, the US Forest Service
The United States Forest Service (USFS) is an agency within the U.S. Department of Agriculture. It administers the nation's 154 national forests and 20 national grasslands covering of land. The major divisions of the agency are the Chief's ...
, the White Mountain Apache Tribe, the Arizona Game and Fish Department, New Mexico Department of Game and Fish, USDA APHIS Wildlife Services, National Park Service
The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List ...
, Species Survival Plan
The American Species Survival Plan or SSP program was developed in 1981 by the (American) Association of Zoos and Aquariums to help ensure the survival of selected species in zoos and aquariums, most of which are threatened or endangered in the w ...
, and Bureau of Land Management
The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands, U.S. federal lands. Headquartered in Washington, D.C., the BLM oversees more than of land, or one ...
.
The IFT has a partnership with Mexico's National Commission for Natural Protected Areas and Directorate General for Wildlife to continue binational collaboration for Mexican wolf recovery.
The IFT employs active conservation. Anti-poaching
Anti-poaching is the organised act to counter the poaching of wildlife. However, it is generally used to describe an overall effort against the illegal wildlife trade. The act of anti-poaching is normally carried out by national parks on public ...
is strongly enforced, as poaching
Poaching is the illegal hunting or capturing of wild animals, usually associated with land use rights.
Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set against the huntin ...
has been found to increase during periods of relaxed protection. Wolf locations, movements, and populations are monitored via tracking collared individuals and the use of remote cameras. The team uses several methods to mitigate predation on livestock. Some pastures are surrounded by fladry (flagging) hung on electrified fences. Range riders accompany cattle to discourage wolf presence. When wolves are spotted near livestock, the range riders employ non-lethal ammunition such as cracker shells and rubber bullet
Rubber bullets (also called rubber baton rounds) are a type of baton round. Despite the name, rubber bullets typically have either a metal core with a rubber coating, or are a homogeneous admixture with rubber being a minority component. Altho ...
s. Wolf packs that live near livestock areas are sometimes given diversionary food caches. Livestock producers are given financial compensation when their animals are killed by wolves, and are paid to remove cattle carcasses in order to discourage wolf scavenging. Individual wolves that are particularly harmful to livestock can be selectively removed, though these management removals have largely decreased over time.
Revised Mexican Wolf Recovery Plan
In September 2022, the US Fish and Wildlife Service published the court-ordered Second Revision of the Recovery Plan. The plan provides a detailed assessment of the population, ecology, threats, management strategies, and future initiatives. It lists several criteria for downlisting (changing the classification from Endangered to Threatened) and delisting (removal of the species from the Federal Lists of Endangered and Threatened Wildlife and Plants).[U.S. Fish and Wildlife Service. 2022. Mexican Wolf Recovery Plan, Second Revision. Region 2, Albuquerque, New Mexico, USA.]
The criteria for delisting in the United States include: a stable or growing population over 8 years, with an average of at least 320 individuals; the implementation of State and Tribal regulations to ensure that the population remains this size or greater; and all available genetic diversity from the captive population is incorporated into the wild via reintroduction. Similar criteria are in place for Mexico, except for a lower minimum population requirement of 200 individuals.
Ecology and behavior
Life history
Mexican wolves live in packs of approximately 4 to 8 individuals, which hunt collaboratively. Like other wolves, Mexican wolves communicate
Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether unintentional or failed transmissions are included and whether communication not only transmit ...
with scent marking
In ethology, territory is the sociographical area that an animal consistently defends against conspecific competition (or, occasionally, against animals of other species) using agonistic behaviors or (less commonly) real physical aggression. ...
, body postures, and a range of calls that include barks, growls, whines, and howling
Howling is a vocal form of animal communication seen in most canines, particularly wolves, coyotes, foxes, and dogs, as well as cats and some species of monkeys. Howls are lengthy sustained sounds, loud and audible over long distances, often with ...
. Packs are typically composed of a monogamous breeding pair
Breeding pair is a pair of animals which cooperate over time to produce offspring with some form of a bond between the individuals. For example, many birds mate for a breeding season or sometimes for life. They may share some or all of the task ...
and their offspring of several years. A pack's home range
A home range is the area in which an animal lives and moves on a periodic basis. It is related to the concept of an animal's territory which is the area that is actively defended. The concept of a home range was introduced by W. H. Burt in 1943. ...
varies based on several factors, including the time of year, pack and litter size, ungulate biomass
Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...
, tree cover, winter snow depth, and human population density. Home ranges average 446 km2; shifting from an average 234 km2 during denning season, to 373 km2 post-denning, to 518 km2 during non-denning season. They frequently make dens in areas near bodies of water, on rough, steep terrain that provides protection. Mexican wolves most frequently inhabit areas away from developed land and open areas, closer to water bodies and dirt roads, and in forested areas with about 16-30% canopy cover. They are typically most active at dawn and the middle of the night, but also can be active at dusk depending on the season. Previous literature has shown gray wolves are most active at dawn and dusk, however, much of this research comes from national parks and protected areas, so it is theorized Mexican wolves have shifted some of their activity to night to avoid people. Mexican wolves breed in February, and gestate for 63 days. They give birth to litters averaging 4–6 pups in April and early May. When wolves reach the age of 1–2 years old, they disperse in search of a mate to begin their own pack. Mexican wolves in the wild typically live 6–8 years.
Diseases
Mexican wolves have been subject to diseases such as canine parvovirus
Canine parvovirus (also referred to as CPV, CPV2, or parvo) is a contagious virus mainly affecting dogs and wolves. CPV is highly contagious and is spread from dog to dog by direct or indirect contact with their feces. Vaccines can prevent thi ...
and canine distemper virus in the wild, and eastern equine encephalitis virus
Eastern equine encephalitis (EEE), also called triple E and sleeping sickness, is a viral disease caused mainly by the Eastern equine encephalitis virus (EEEV). Most infections in humans are asymptomatic, but about 5% of the time the infection p ...
in captivity.
Diet
Mexican wolves, like other wolves worldwide, are opportunistic predators and primarily prey
Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not ki ...
on large ungulate
Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with Hoof, hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined ...
s. In the United States population, Rocky Mountain elk
The Rocky Mountain elk (''Cervus canadensis nelsoni'') is a subspecies of elk found in the Rocky Mountains and adjacent ranges of Western North America.
Description
The Rocky Mountain Elks are the second largest animals in the elk subfamily, ...
(''Cervus canadensis nelsoni'') make up about 76–80% of their prey. The most common demographic of elk
The elk (: ''elk'' or ''elks''; ''Cervus canadensis'') or wapiti, is the second largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia. ...
that are predated on are calves, which make up two thirds of all native ungulates that the wolves prey on. Elk appear to attempt to balance their nutritional demands with predation risk from Mexican wolves seasonally and incorporate both proactive and reactive responses to mitigate predation risk from Mexican wolves (and mountain lions). They also spend a greater proportion of time foraging and vigilant, and a lower proportion of time resting, in areas with greater wolf predation risk. Other native prey include mule deer
The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer.
Unlike the related whit ...
(''Odocoileus hemionus''), Coues white-tailed deer
The white-tailed deer (''Odocoileus virginianus''), also known Common name, commonly as the whitetail and the Virginia deer, is a medium-sized species of deer native to North America, North, Central America, Central and South America. It is the ...
(''Odocoileus virginianus couesi''), collared peccary
The collared peccary (''Dicotyles tajacu'') is a peccary, a species of artiodactyl (even-toed) mammal in the family Peccary, Tayassuidae found in North America, North, Central America, Central, and South America. It is the only member of the gen ...
(''Dicotyles tajacu''), wild turkey
The wild turkey (''Meleagris gallopavo'') is an upland game bird native to North America, one of two extant species of Turkey (bird), turkey and the heaviest member of the order Galliformes. It is the ancestor to the domestic turkey (''M. g. dom ...
(''Meleagris gallopavo''), and small mammals such as rabbits and squirrels. Up to 16% of their diet may include domestic cattle (''Bos taurus'') in certain parts of their range, especially in locations where the cattle graze and calve year-round as opposed to seasonally. Investigations have suggested that reports of wolf depredation on livestock were sometimes exaggerated or fabricated. As a result, the Recovery Program has adopted more stringent standards of proof to determine which animals were killed by wolves.
The diet of wolves in Mexico differs from that of the United States population due to the absence of elk and most other wild ungulates in the wolves' Mexican range. In Mexico, white-tailed deer make up approximately 36% of their diet, while domestic cattle comprise about 25% and diversionary food caches from wildlife managers provide an additional 22%. The rest of their diet predominantly consists of smaller prey including wild turkeys, rabbits (''Sylvilagus'' spp.), skunks (''Mephitis'' spp.), squirrels (''Otospermophilus variegatus''), and other small mammals and birds, with very occasional collared peccaries and domestic horses (''Equus caballus'').
Competition
Mexican wolves share their habitat and prey with other carnivores, including mountain lions (''Puma concolor''), American black bear
The American black bear (''Ursus americanus''), or simply black bear, is a species of medium-sized bear which is Endemism, endemic to North America. It is the continent's smallest and most widely distributed bear species. It is an omnivore, with ...
s (''Ursus americanus''), coyote
The coyote (''Canis latrans''), also known as the American jackal, prairie wolf, or brush wolf, is a species of canis, canine native to North America. It is smaller than its close relative, the Wolf, gray wolf, and slightly smaller than the c ...
s (''Canis latrans''), bobcat
The bobcat (''Lynx rufus''), also known as the wildcat, bay lynx, or red lynx, is one of the four extant species within the medium-sized wild cat genus '' Lynx''. Native to North America, it ranges from southern Canada through most of the c ...
s (''Lynx rufus''), red fox
The red fox (''Vulpes vulpes'') is the largest of the true foxes and one of the most widely distributed members of the order Carnivora, being present across the entire Northern Hemisphere including most of North America, Europe and Asia, plus ...
es (''Vulpes vulpes'') and gray fox
The gray fox (''Urocyon cinereoargenteus''), or grey fox, is an omnivorous mammal of the family Canidae, widespread throughout North America and Central America. This species and its only congener (biology), congener, the diminutive island fox ...
es (''Urocyon cinereoargenteus''). Historically, they also once competed with the locally extinct jaguar
The jaguar (''Panthera onca'') is a large felidae, cat species and the only extant taxon, living member of the genus ''Panthera'' that is native to the Americas. With a body length of up to and a weight of up to , it is the biggest cat spe ...
(''Panthera onca'') and the currently extinct Mexican grizzly bear (''Ursus arctos''). Unlike wolves elsewhere, Mexican wolves do not significantly affect the behavior or populations of competing carnivore species.
Habitat
The Mexican wolf's range is predominantly located in the Apache-Sitgreaves National Forest and the Gila National Forest
The Gila National Forest is a United States national forest in New Mexico. Established in 1905, it now covers approximately , making it the sixth largest national forest in the continental United States. The Forest administration also manage ...
, a mountainous ecosystem with many lakes, streams, and other varied terrain. In this region, the most common habitat types are Ponderosa pine forest, pinyon-juniper woodland, and Madrean encinal and pine-oak woodland. Other habitat includes mixed-conifer forest, semi-desert grassland, Great Basin
The Great Basin () is the largest area of contiguous endorheic watersheds, those with no outlets to the ocean, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja Californi ...
and Colorado Plateau
The Colorado Plateau is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the Southwestern United States. This plateau covers an area of 336,700 km2 (130,000 mi2) within w ...
grassland-steppe, subalpine grassland, aspen
Aspen is a common name for certain tree species in the Populus sect. Populus, of the ''Populus'' (poplar) genus.
Species
These species are called aspens:
* ''Populus adenopoda'' – Chinese aspen (China, south of ''P. tremula'')
* ''Populus da ...
forest, and spruce-fir forest.[Vander Lee, B., Smith, R., & Bate, J. (2004). Ecological & Biological Diversity of the Apache-Sitgreaves National Forests In Ecological and Biological Diversity of National Forests in Region 3. ''The Nature Conservancy''.] Aspen research suggests that Mexican wolves have not yet altered elk behavior and populations so as to trigger a trophic cascade
Trophic cascades are powerful indirect interactions that can control entire ecosystems, occurring when a trophic level in a food web is suppressed. For example, a top-down cascade will occur if predators are effective enough in predation to redu ...
in the manner observed in Yellowstone National Park
Yellowstone National Park is a List of national parks of the United States, national park of the United States located in the northwest corner of Wyoming, with small portions extending into Montana and Idaho. It was established by the 42nd U ...
(e.g. facilitating aspen regeneration), likely due to the fact that the Mexican wolves still have a relatively small, highly dispersed population.
This habitat contains at least 537 plant and animal species. Additional mammals include Abert's squirrels, white-nosed coati
The white-nosed coati (''Nasua narica''), also known as the coatimundi (), is a species of coati and a member of the family Procyonidae (raccoons and their relatives). Local Spanish names for the species include ''antoon'', ''gato solo'', ''pi ...
s, ringtail
The ringtail (''Bassariscus astutus'') is a mammal of the raccoon family native to arid regions of North America. It is widely distributed and well-adapted to its distributed areas. It has been legally trapped for its fur. Globally, it is list ...
s, bighorn sheep
The bighorn sheep (''Ovis canadensis'') is a species of Ovis, sheep native to North America. It is named for its large Horn (anatomy), horns. A pair of horns may weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates th ...
, and pronghorn
The pronghorn (, ) (''Antilocapra americana'') is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American ante ...
. Birds vary from raptors like Mexican spotted owls, Apache northern goshawks, and bald eagle
The bald eagle (''Haliaeetus leucocephalus'') is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a species pair with the white-tailed eagle (''Haliaeetus albicilla''), which occupies the same niche ...
s; to waterfowl such as American white pelican
The American white pelican (''Pelecanus erythrorhynchos'') is a large aquatic soaring bird from the order Pelecaniformes. It breeds in interior North America, moving south and to the coasts, as far as Costa Rica, in winter.
Taxonomy
The Americ ...
s (''Pelecanus erythrorhynchos''), tundra swans (''Cygnus columbianus''), and pied-bill grebes (''Podilymbus podiceps''); to songbirds like the pygmy nuthatch (''Sitta pygmaea''). Streams are inhabited by native fishes including Apache trout (''Oncorhynchus apache''), Bluehead and desert sucker (''Catostomus discobolus'' and ''C. clarkii''), Loach Minnow
The loach minnow (''Tiaroga cobitis'') is a species of freshwater Actinopterygii, ray-finned fish belonging to the Family (biology), family Leuciscidae, the shiners, daces and minnows. It is the only species in the monospecific genus ''Tiaroga''. ...
(''Rhinichthys cobitis''), Roundtail Chub
The roundtail chub (''Gila robusta'') is a species of freshwater ray-finned fish belonging to the family Leuciscidae, which includes the daces, chubs, Eurasian minnows and related species. This species is found in southwestern North America. I ...
(''Gila robusta''), and many more. Local reptiles and amphibians include bullsnakes, black-tailed rattlesnakes, crevice spiny lizards, and New Mexico spadefoot toads.
In popular culture
A Mexican wolf pack features in Ernest Thompson Seton
Ernest Thompson Seton (born Ernest Evan Thompson; August 14, 1860 – October 23, 1946) was a Canadian and American author, wildlife artist, founder of the Woodcraft Indians in 1902 (renamed Woodcraft League of America), and one of the foun ...
's 1898 short story " Lobo, the King of Currumpaw." The story, largely based on Seton's real-life experience, features Lobo and his mate, Blanca, the alpha pair of their pack, who predate upon the vast herds of livestock on the Currumpaw ranch in New Mexico. Seton tells about the conflict between the wolves and the many hunters and trappers who they outwit, until Seton himself manages to kill the breeding pair. In a rarity for the time, Seton portrayed the wolves in a sympathetic light, and himself, the hunter, as the antagonist. Seton became an advocate for wolf conservation later in his life as a result of his experience. Lobo's pelt is on display at Philmont Scout Ranch
Philmont Scout Ranch is a ranch located in Colfax County, New Mexico, United States, near the village of Cimarron. Donated by oil baron Waite Phillips, the ranch is owned by Scouting America. It is a high adventure base where crews of Scouts ...
in Cimarron, New Mexico.
Decades later, conservationist Aldo Leopold
Aldo Leopold (January 11, 1887 – April 21, 1948) was an American writer, Philosophy, philosopher, Natural history, naturalist, scientist, Ecology, ecologist, forester, Conservation biology, conservationist, and environmentalist. He was a profes ...
had a similar life changing encounter when he killed a Mexican wolf in the Gila Wilderness in 1909. In his famous essay, Thinking Like a Mountain, Leopold highlighted the “green fire” in the dying wolf's eyes to provide empathy to the animal, while also explaining the ecological benefits that wolves provide to their habitat. Like Seton, Leopold would go on to become an advocate for predator conservation.
In 2023 the Mexican wolf was featured on a United States Postal Service
The United States Postal Service (USPS), also known as the Post Office, U.S. Mail, or simply the Postal Service, is an independent agencies of the United States government, independent agency of the executive branch of the federal governmen ...
Forever stamp as part of the ''Endangered Species'' set, based on a photograph from Joel Sartore's ''Photo Ark''. The stamp was dedicated at a ceremony at the National Grasslands Visitor Center in Wall, South Dakota
Wall (Lakota language, Lakota: ''Makȟóšiča Aglágla Otȟuŋwahe'', "Town alongside the Badlands National Park, Badlands") is a town in Pennington County, South Dakota, Pennington County, South Dakota, United States. The population was 699 at ...
.
See also
* California Wolf Center
* Ex-situ conservation
* Endangered Wolf Center
* Wolf reintroduction
Wolf reintroduction involves the reintroduction of a portion of grey wolves in areas where native wolves have been extirpated. More than 30 subspecies of ''Canis lupus'' have been recognized, and grey wolves, as colloquially understood, compr ...
Notes
References
Further reading
* Bass, Rick (2007), ''The New Wolves: The Return of the Mexican Wolf to the American Southwest'', Globe Pequot. (Originally published 1998)
* Holaday, B. (2003), ''Return of the Mexican Gray Wolf: Back to the Blue'', University of Arizona Press,
*
* McCarthy, Cormac (1994), ''The Crossing'', Everyman's Library Knopf, , A poignant fictional account of a young cowboy's capture of a wolf.
* Robinson, M. (2005), ''Predatory Bureaucracy: The Extermination of Wolves and the Transformation of the West'', University Press of Colorado,
* Shaw, H. (2002), ''The Wolf in the Southwest: The Making of an Endangered Species'', High-Lonesome Books,
External links
The Mexican Wolf Recovery Plan
FWS
Mexican Gray Wolves in the Southwest
USDA APHIS Wildlife Services
Mexicanwolves.org
{{Taxonbar, from=Q531300
Subspecies of Canis lupus
Carnivorans of North America
Mammals of Mexico
Mammals of the United States
Wolves in the United States
Fauna of Northern Mexico
Fauna of Northeastern Mexico
Fauna of the Southwestern United States
Fauna of the Chihuahuan Desert
Fauna of the Sonoran Desert
Natural history of the Mexican Plateau
Biota of New Mexico
Natural history of Arizona
Natural history of Sonora
Mammals described in 1929
Taxa named by Edward William Nelson
Wolves
Endangered biota of Mexico
Endangered fauna of the United States
Endangered fauna of North America
ESA endangered species
Fauna of the Sierra Madre Occidental