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), also known as the lobo, is a subspecies of gray wolf native to the Sierra Madre and the surrounding area of western Mexico, though its range once included the southeastern United States. It is the smallest of North America's gray wolves, 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. Its ancestors were likely the first gray wolves to enter North America, as indicated by its southern range and basal physical and genetic characteristics.
Though once held in high regard in Pre-Columbian Mexico, 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 placed on the ESA in 1976, captive-bred Mexican wolves were released into recovery areas in Arizona and New Mexico in the late 1990s in order to assist the animals' recolonization of their former historical range.
Taxonomy and evolution
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, 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 C. l. nubilus.
Hybridization with coyotes
An analysis of controlled-region haplotypes of the mitochondrial DNA and sex chromosomes of Mexican wolves by Uppsala University detected the presence of coyote markers in some specimens. However, these markers were absent in captive Mexican wolf populations, thus suggesting that some male wolves from remnant wild populations began mating with female coyotes and coywolf hybrids, later backcrossing to other male wolves. Analysis on Texan coyote haplotypes also detected the presence of male wolf introgression, such as wolf Y-chromosomes 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 wolf, thus indicating that a male coyote had also managed to breed with a female Mexican wolf in the wild. The Mexican wolf may be the only gray wolf in the southern states besides 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, 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. It has been suggested that the hybrid animal was afflicted with sarcoptic mange, which would explain its hairless and blueish appearance.
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 in order to breed resistant, loyal but temperamental, and good 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.
There was a rapid reduction of Mexican wolf populations in the southwestern USA 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. 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. 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 canid species.
The Mexican wolf persisted longer in Mexico, as human settlement, ranching and predator removal came later than in the southwestern USA. 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 ESA in 1976, with the Mexican Wolf Recovery Team being formed three years later by the FWS. 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 to 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.
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. 92 wolf deaths were recorded since 1998, with four occurring in 2012, these four were all due to illegal shootings.
- Holaday, B. (2003), Return of the Mexican Gray Wolf: Back to the Blue, University of Arizona Press, ISBN 0816522960
- Shaw, H. (2002), The Wolf in the Southwest: The Making of an Endangered Species, High-Lonesome Books, ISBN 0944383599
- 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
- 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.
- 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.
- Valadez, R., Rodríguez, B., Manzanilla, L. & Tejeda, S. (2006), Dog-wolf hybrid biotype reconstruction from the archaeological city of Teotihuacan in prehispanic central Mexico, in Dogs and People in Social, Working, Economic or Symbolic Interaction, ed. L. M. Snyder & E. A. Moore, pp. 121-131, Oxford, England: Oxbow Books (Proceedings of the 9th ICAZ Conference, Durham, England, 2002.
- Nie, M. A. (2003), Beyond Wolves: The Politics of Wolf Recovery and Management, University of Minnesota Press, pp. 118-119, ISBN 0816639787
- Nelson, E. W. and Goldman, E. A. (1929), A new wolf from Mexico, Journal of Mammalogy 10:165–166.
- Hailer, F., and J. A. Leonard, (2008) Hybridization among three native North American Canis species in a region of natural sympatry, PLoS One 3:e3333
- USFWS, (1982), Mexican wolf recovery plan, U.S. Fish and Wildlife Service, Albuquerque, New Mexico.
- USFWS (2012), Mexican Wolf Recovery Program: Progress Report #15, US Fish and Wildlife Service
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