Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (5000-20,000 square km (about 2000-8000 square miles)) Range formerly extended from southern Arizona, southern New Mexico, and western Texas south through much of northern and central Mexico. As of the mid-1990s, none occurred in the U.S. and very few or none remained in Mexico (most likely in eastern Sonora, western Chihuahua, and Zacatecas) (Johnson 1991; USFWS, Federal Register, 1 May 1996). In 1998, reintroductions began within an area (Blue Range Wolf Recovery Area) encompassing a portion of eastern Arizona and western New Mexico. This area is part of a larger "Nonessential Experimental Area" extending across much of Arizona and New Mexico and a small portion of far western Texas. Currently, free-ranging wolves exist in both Arizona and New Mexico (USFWS 2013).
See Hoffmeister (1986) for information on runways or hunting beats that historically were used in southern Arizona.
occurs (regularly, as a native taxon) in multiple nations
Length: 205 cm
Weight: 59000 grams
Catalog Number: USNM 98312
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Preparation: Skin; Skull
Collector(s): E. Nelson & E. Goldman
Year Collected: 1899
Locality: Colonia Garcia, 60 Mi SW Of Casas Grandes, Chihuahua, Mexico, North America
Elevation (m): 2042
- Type: Nelson, E. W. & Goldman, E. A. 1929 May 09. Journal of Mammalogy. 10: 165.
Sierra Madre Occidental Pine-oak Forests Habitat
This taxon is found in the Sierra Madre Occidental pine-oak forests ecoregion, which boasts some of the richest biodiversity anywhere in North America, and contains about two thirds of the standing timber in Mexico. Twenty-three different species of pine and about 200 species of oak reside within the Sierra Madre Occidental pine-oak forests ecoregion.
Pine-oak forests here typically grow on elevations between approximately 1500 and 3300 meters, and occur as isolated habitat islands in northern areas within the Chihuahuan Desert. Soils are typically deep, where the incline allows soil build-up and derived from igneous material, although metamorphic rocks also form part of the soils in the west and northwest portions of the sierra. Steep-sloped mountains have shaped some portions of the Sierra, while others are dominated by their deep valleys, tall canyons and cliffs. These steep-sided cliffs have thinner soils limiting vegetation to chaparral types; characterized by dense clumps of Mexican Manzanita (Arctostaphylos pungens), Quercus potosina and Netleaf Oak (Q. rugosa). There are also zones of natural pasture, with grasses from the genera Arisitida, Panicum, Bromus and Stevis.
The pine-oak forests gradually transform into an oak-grassland vegetative association. Such communities represent an ecological transition between pine-oak forests and desert grasslands.. Here, species such as Chihuahuan Oak (Quercus chihuahuensis), Shin Oak (Q. grisea), Q. striatula and Emory Oak (Q. emoryi), mark a transition zone between temperate and arid environments, growing in a sparse fashion and with a well-developed herbaceous stratum resembling xeric scrub. Cacti are also part of these transition communities extending well into the woodlands. Some cacti species such as the Little Nipple Cactus (Mammillaria heyderi macdougalii), Greenflower Nipple Cactus (M. viridiflora), Mojave Mound Cactus (Echinocereus triglochidiatus), and Leding's Hedgehog Cactus (E. fendleri var. ledingii) are chiefly centered in these biotic communities. The dominant vegetation in the northernmost part of the ecoregion in the Madrean Sky Islands includes Chihuahua Pine (Pinus leiophylla), Mexican Pinyon (P. cembroides), Arizona Pine (P. arizonica), Silverleaf Oak (Quercus hypoleucoides), Arizona White Oak (Q. arizonica), Emory Oak (Q. emoryi), Netleaf Oak (Q. rugosa), Alligator Juniper (Juniperus deppeana), and Mexican Manzanita (Arctostaphylos pungens).
This ecoregion is an important area for bird richness and bird endemism. Likewise, virtually all of the ecoregion is included in the Sierra Madre Occidental and trans-mexican range Endemic Bird Area. Endemic bird species include the Thick-billed Parrot (Rhynchopsitta pachyrhyncha EN) which is in danger of extinction, with population estimates as low as 500 pairs; the Tufted Jay (Cyanocorax dickeyi NT), Eared Quetzal (Euptilptis neoxenus NT) and the Green-striped Brush Finch (Buarremon virenticeps). Temperate and tropical influences converge in this ecoregion, forming a unique and rich complex of flora and fauna. Many other birds are found in this ecoregion including the Green Parakeet (Aratinga holochlora), Eared Trogon (Euptilotis neoxenus NT), Coppery-tailed Trogon (Trogon elegans), Grey-breasted Jay (Aphelocoma ultramarina), Violet-crowned Hummingbird (Amazilia violiceps), Spotted Owl (Strix occidentalis NT), and Golden Eagle (Aguila chryaetos). Some species found only in higher montane areas are the Gould's Wild Turkey (Meleagris gallopavo mexicana), Band-tailed Pigeon (Patagioenas fasciata), Mexican Chickadee (Poecile sclateri) and Hepatic Tanager (Piranga flava).
The Sierra Madre Mantled Ground Squirrel (Spermophilus madrensis NT) is an endemic to the Sierra Madre Occidental pine-oak forests, restricted to southwestern Chihuahua, Mexico. The Mexican Gray Wolf (Canis lupus baileyi) and Mexican Grizzly Bear (Ursus horribilis), although considered by most to be extinct from this ecoregion, once roamed these mountains. Mammals also present include White-tailed Deer (Odocoileus virginianus), American Black Bear (Ursus americanus), Buller’s Chipmunk (Tamias bulleri), endemic Zacatecan Deer Mouse (Peromyscus difficilis), rock Squirrel (Spernophilis variegatus), Zacatecas Harvest Mouse (Reithrodontomys zacatecae) and Coati (Nasua nasua), to set forth a subset of mammals present.
Reptiles are also numerous in this ecoregion. Fox´s Mountain Meadow Snake (Adelophis foxi) is an endemic taxon to the ecoregion, only observed at the type locality at four kilometers east of Mil Diez, about 3.2 kilometers west of El Salto, in southwestern Durango, Mexico. There are at least six species of rattlesnakes including the Mexican Dusky Rattlesnake (Crotalis triseriatus), Mojave Rattlesnake (C. scutulatus), Rock Rattlesnake (C. lepidus), Western Diamondback Rattlesnake (C. atrox), Twin-spotted Rattlesnake (C. pricei), and Ridgenose Rattlesnakes (C. willardi). Clark's Spiny Lizard (Sceloporus clarkii) and Yarrow's Spiny Lizard (S. jarrovii), Bunchgrass Lizard (S. scalaris), and Striped Plateau Lizard (S. virgatus) are several of the lizards found in the Sierra Madre Occidental pine-oak forests.
Along springs and streams the Western Barking Frog (Craugastor augusti) and the Tarahumara Frog (Rana tamahumarae) are two anuran taxa occurring in the ecoregion. Other anuran taxa found here include: Bigfoot Leopard Frog (Lithobates megapoda), Northwest Mexico Leopard Frog (Lithobates magnaocularis) and the Blunt-toed Chirping Frog (Eleutherodactylus modestus VU). The Sacramento Mountains Salamander (Aneides hardii) is an endemic salamander found in the Sierra Madre Occidental pine-oak forests, restricted to the Sacramento Mountains, Capitan Mountains, and Sierra Blanca in Lincoln and Otero Counties within southern New Mexico, USA.
- World Wildlife Fund & C. Michael Hogan. 2013."Sierra Madre Occidental pine-oak forests". Encyclopedia of Earth, National Council for Science and the Environment, Washington DC ed. Rodney L. Honeycutt.
- David E. Brown, ed. 1994. Biotic Communities: Southwestern United States and Northwestern Mexico. University of Utah Press, Salt Lake City, Utah. ISBN: 0874804590
Comments: These wolves are not limited to any particular habitat type, but viable populations occur only where human population density and persecution level are low and prey densities are high. Young are born in a den that may be on a bluff or slope among rocks or in an enlarged badger hole (Hoffmeister 1986).
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
These wolves probably are similar to other subspecies as follows: annual home range up to several hundred square kilometers; may occasionally move several hundred kilometers, especially dispersing young. Historical information indicates that a hunting runway of 70 miles would be traversed about every nine days (see Young and Goldman 1944, Hoffmeister 1986).
Comments: Ungulates are the predominant prey. When ungulate populations are low or seasonally unavailable, wolves may eat alternative prey such as lagomorphs, rodents, and carrion. Reintroduced wolves in Arizona and New Mexico subsist primarily on elk and sometimes take livestock, deer, rodents, or lagomorphs (Merkle et al. 2009). Runways or hunting beats follow stream beds, washes, old game trails, and old roads and mostly occur in open country (Young and Goldman 1944).
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 1 - 5
Comments: This subspecies is represented by only one extant occurrence in Arizona-New Mexico (USFWS 2013). It is unlikely that a viable population exists in Mexico.
50 - 250 individuals
Comments: At least 75 Mexican wolves existed in the wild in Arizona and New Mexico at the end of 2012 (compared to the 2011 minimum population count of 58 wolves) (USFWS 2013). All but one of the 75 wolves were born in the wild (versus captive born). The 2012 minimum population count included at least 20 wild-born pups that survived through the end of the year (USFWS 2013). The number of wolves in Mexico is unknown but likely quite small.
These wolves probably are similar to other subspecies as follows: packs consist of one or more family groups with dominance hierarchy; population density low; generally not instrumental in causing prey declines, the effect varying with other circumstances.
Life History and Behavior
Comments: Mainly nocturnal
Gestation lasts about 2 months. Young are born in March and early April (Hoffmeister 1986). Litter size may average around 6-7; one litter/year. Only the dominate male/female mate and rear offspring. Young are tended by both parents. Young and parents leave den when young are about 3 months old. Pups are weaned probably in about 5-7 weeks. Some offspring remain with pack, others disperse as they mature. Breeding first occurs during the second or third year (Hoffmeister 1986).
National NatureServe Conservation Status
Rounded National Status Rank: N1 - Critically Imperiled
NatureServe Conservation Status
Rounded Global Status Rank: T1 - Critically Imperiled
Reasons: Historically widespread in the southwestern United States and adjacent Mexico; extirpated from all or nearly all of historical range, mainly as a result of trapping and poisoning, plus some habitat loss from human encroachment; reintroduced into a recovery area in Arizona and adjacent New Mexico; as of early 2013, the wild population was increasing and included at least 75 individuals, all but one of which were born in the wild.
Global Short Term Trend: Relatively stable to increase of 25%
Comments: Reintroduced population in Arizona-New Mexico has been increasing in recent years (USFWS 2013).
Global Long Term Trend: Decline of >90%
Comments: Distribution and abundance have decreased greatly over the long term.
Degree of Threat: Low
Comments: Historically this subspecies was widespread, then it was exterminated from essentially all of the range through trapping, poisoning, shooting, and reduction of prey resources. Habitat within the historical range has greatly decreased as a result of human encroachment. In the reintroduced population in Arizona-New Mexico, up to several individuals die each year as a result of illegal shooting, and 0-2 are killed each year by collisions with vehicles (USFWS 2013).
Needs: USFWS Recovery Program covers most needs. Protect large areas with potential habitat. Promote reintroduction effort. The goal of the Mexican wolf recovery plan is to establish a viable, self-sustaining population of at least 100 individuals in the middle to high elevations of a 5000-square-mile area somewhere within the historic range (Johnson 1991).
Relevance to Humans and Ecosystems
Stewardship Overview: Ongoing major management includes propagation in captivity, releases of captive-bred wolves to improve the genetic makeup of the wild population, habitat management to increase the capacity of the area to support more wolves, actions to decrease wolf-livestock interactions, and compensation to livestock producers to offset the costs of wolf depredations (USFWS 2013).
The U.S. Fish and Wildlife Service Southwest Region has initiated the revision of the 1982 Mexican Wolf Recovery Plan. In December 2010, the Southwest Regional Director appointed a new recovery team to develop a revised recovery plan for the Mexican wolf. The Mexican Wolf Recovery Team includes a Tribal Liaisons Subgroup, Stakeholder Liaisons Subgroup, Agency Liaisons Subgroup, and a Science and Planning Subgroup. When completed and approved by the Southwest Regional Director, the Revised Mexican Wolf Recovery Plan will include objective and measurable recovery criteria for removing the Mexican wolf from the List of Threatened and Endangered Wildlife and Plants, management actions that will achieve the criteria, and time and cost estimates for these actions. USFWS will begin exploring options for implementation of the Revised Mexican Wolf Recovery Plan's recovery actions in 2013 and beyond. Source: USFWS (2013).
The Blue Range Mexican Wolf reintroduction project is managed by the U.S. Fish and Wildlife Service in collaboration with the following cooperating agencies: Arizona Game and Fish Department, USDA Forest Service, USDA-APHIS Wildlife Services, and the White Mountain Apache Tribe. These agencies, along with the Arizona counties of Graham, Greenlee, and Navajo, work together under a formal memorandum of understanding that provides a framework for collaboration (USFWS 2013).
The Mexican wolf (Canis lupus baileyi) is a subspecies of the gray wolf native to the Sierra Madre and the surrounding area of western Mexico. Its original range also encompassed the southeastern United States. It is the smallest of North America's gray wolves, and is typically of a dark grizzly color.
Genetic and morphological studies indicate that the Mexican wolf is the most basal and genetically distinct of North American gray wolves, being more closely related to Old World wolves rather than other New World subspecies. Its ancestors were likely the first gray wolves to cross the Bering Land Bridge into North America during the Pleistocene, colonizing most of the continent until pushed southwards by the newly arrived ancestors of Canis lupus nubilus.
The Mexican wolf is the smallest grey wolf subspecies present in North America. Reaching an overall length no greater than 1.2–1.5 metres (3.9–4.9 ft) and a maximum height of about 80 centimetres (31 in), it is around the size of a German Shepherd. Weight ranges from 27–37 kilograms (60–82 lb). In stature, it resembles some European wolves, though its head is usually broader, its neck thicker, its ears longer and its tail shorter.
The Mexican wolf was described by both naturalists Hernández and Fernandez and is named for Vernon Bailey, an American naturalist and specialist in mammalogy who participated in the Biological Survey of Texas during the late 19th century.
Former range and extirpation
Until recent times, the Mexican wolf ranged the Sonoran and Chihuahuan Deserts from central Mexico to western Texas, southern New Mexico, and central Arizona. (Recent studies completed by genetics experts show evidence of Mexican wolves ranging as far north as Colorado). By the turn of the 20th century, reduction of natural prey like deer and elk caused many wolves to begin attacking domestic livestock, which led to intensive efforts by government agencies and individuals to eradicate the Mexican wolf. Hunters also hunted down the wolf because it killed deer. Trappers and private trappers have also helped in the eradication of the Mexican wolf. These efforts were very successful, and by the 1950s, the Mexican wolf had been eliminated from the wild. In 1976, the Mexican wolf was declared an endangered subspecies and has remained so ever since. Today, an estimated 340 Mexican wolves survive in 49 facilities in the United States and Mexico.
Reintroduction to the Southwest
In 1997, controversy arose when a mostly captive pack at Carlsbad Caverns National Park designated for release was found by Roy McBride, who had captured many wolves for the recovery program in the 1970s, to be largely composed of wolf-dog hybrids. Though staff initially argued that the animals' odd appearance was due to captivity and diet, it was later decided to euthanize them.
In March 1998, the United States Fish and Wildlife Service (USFWS) began reintroducing Mexican wolves into the Blue Range area of Arizona. The overall objective of this program was to reestablish 100 Mexican wolves in the Apache and Gila National Forests of Arizona and New Mexico by 2008.
On March 30, 1998, government biologists released 11 grey wolves – 3 adult males, 3 adult females, 3 female pups and yearlings and 2 male pups — from 3 chain-link acclimation pens within the 18,130 square kilometres (7,000 sq mi), federally designated Blue Range Wolf Recovery Area in east-central Arizona.
A population count completed by the Interagency Field Team (IFT) in the winter of 2006–2007 estimated 60 wolves living in the recovery area in several packs. The population goal for 2006 was 100 wolves. In early 2011 there were only two breeding pairs and the population count was 50, up from 42 in the early 2010 count. As of February 2012, the number of breeding pairs rose to six, with a total population count of 58, including 32 wolves in six packs on the Arizona side of the recovery area and 26 wolves in six packs on the New Mexico side. There were 18 pups born in 2011 that survived through Dec. 31, 2011. Nine wolves died in 2011; two were shot illegally. The most recent count at the end of 2012 counted 75 wolves. However, only 3 breeding pairs were counted out of the 13 confirmed packs. There were 20 pups that had survived until the end of the year.
In February 2010, three captive Mexican wolves living in the Wildlife Science Center in Forest Lake, Minnesota, escaped from their pen after it was pried open by unknown individuals. Two of the wolves came back on their own the next day; the third wolf, the alpha of the pack, had to be chased down in suburban areas until captured.
Captive breeding programs
There are 47 Mexican wolf breeding facilities in United States and Mexico with the largest in the world being the Endangered Wolf Center near St.Louis, Missouri, which was founded in 1971 by naturalist Marlin Perkins. Learn more about the Endangered Wolf Center at http://www.endangeredwolfcenter.org. Another captive breeding center that was founded in 1977 is the California Wolf Center located in Julian, California. The Center is the third largest breeding and host facility for Mexican grey wolves in the United States.
Hybridizations with coyotes
In an evolutionary biology research conducted by a team of researchers in the Uppsala University, analysis of controlled-region haplotypes of the mitochondrial DNA and sex chromosomes from Mexican grey wolves detected the presence of coyote markers in some of the wolves. However, these markers were not detected in any of the captive Mexican grey wolves.  This study suggests that when the subspecies was depleted in the wild from persecutions, some of the male wolves from the remnant populations began seeking potential mates in the female coyotes with the female coywolf hybrid offsprings later backcrossing to other male wolves while the male hybrids may have backcrossed with the female coyotes. Analysis on the haplotypes from coyotes in Texas also detected the presence of male wolf introgression such as Y-chromosomes from the grey wolves in some of the male coyotes. In an extremely rare case, the study found that one coyote out of seventy individuals from Texas was discovered to carry a mtDNA haplotype derived from a female Mexican grey wolf implicating that a male coyote had also managed to breed with a female Mexican grey wolf in the wild. The Mexican grey wolves may be the only grey wolf subspecies in the southern states besides the domestic and feral dogs to have hybridized with coyotes.
In tests performed on a sample from a taxidermied carcass of what was initially labelled as a chupacabra, mtDNA analysis conducted by Texas State University professor Michael Forstner showed that it was a coyote. 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. It has been suggested that the hybrid animal was afflicted with sarcoptic mange, which would explain its hairless and blueish appearance.
Canis lupus baileyi
A captive, resting Mexican wolf at the Minnesota Zoo
A captive Mexican wolf running in its zoo enclosure at the National Zoo in Washington D.C.
At the Arizona-Sonora Desert Museum
- USFWS Wolf Recovery in North America(2007)
- Mech, L. David (1981), The Wolf: The Ecology and Behaviour of an Endangered Species, University of Minnesota Press, p. 350, ISBN 0-8166-1026-6
- Chambers SM, Fain SR, Fazio B, Amaral M (2012). "An account of the taxonomy of North American wolves from morphological and genetic analyses". North American Fauna 77: 1–67. Retrieved 2013-07-02.
- The Natural History of Dogs: Canidæ Or Genus Canis of Authors. Including Also the Genera Hyæna and Proteles by Charles Hamilton Smith, contributor William Home Lizars, Samuel Highley, W. Curry, Junr. & Co, Published by W.H. Lizars, ... S. Highley, ... London; and W. Curry, jun. and Co. Dublin., 1839
- Schmidly, David J. (2002). Texas Natural History: A Century of Change. Lubbock: Texas Tech University Press. ISBN 0896724697.
- USFWS Species Survival Plan Captive Facilities
- "Letter from Roy McBride to David Parsons". Retrieved 18 November 2013.
- Jason Manning: "The Wolf in Texas". The Wild World of Wolves on wildworldofwolves.tripod.com
- Shaun McKinnon (2012-02-03). "Grey wolf numbers up, still below goal". Arizona Republic. Retrieved 2012-02-11.
- Dunbar, Elizabeth (18 February 2010). "Missing Mexican wolf found in New Brighton". MPR News. Retrieved 15 November 2010.
- Carbery, Kevin (17 April 2008). "Wolves welcome in Jefferson County". St Louis Today – Suburban Journal. Retrieved 15 November 2010.
- "Lost Lobos: Local Wolf Experts Voice Dismay Over Killing of 3 Rare Mexican Wolves". East County Magazine. 2010-07-21. Retrieved 2010-07-30.
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