Mexican Wolf

Mexican wolf standing in a snowy grassland.
The female Mexican wolf, Asha, in Valles Caldera National Preserve on December 3, 2023.

Courtesy of Bryan Ramsay

The Mexican wolf (Canis lupus baileyi) is the smallest and most genetically distinct of the gray wolf subspecies. They historically were found roaming the Desert Southwest—New Mexico, Arizona, Texas, and southern Utah and Colorado—in forested, high-elevation (above 4,500 feet (1372 m)) mountainous terrain. Sadly, they were brought to the verge of extinction by intentional human eradication efforts.

They have been listed as an endangered species since 1976. As a listed endangered species, Mexican wolves outside of the experimental area are fully protected under the Endangered Species Act.

Until November 2023, Mexican wolves were not seen in Valles Caldera for more than 90 years. While the Mexican wolf, Asha or F2754, was captured by the New Mexico Game and Fish after she left the park and wandered up near Coyote, New Mexico on December 9, the park provides suitable habitat for wolves. They prefer mountain woodlands with elk, mule deer, rabbits, and small mammals to hunt. With abundant prey and nearly 90,000 acres in size, Valles Caldera is also considered large enough to support a wolf pack.

Valles Caldera National Preserve was established by Congress to protect, preserve, and restore the fish, wildlife, watershed, natural, scientific, scenic, geologic, historic, cultural, archaeological, and recreational values of the area. A return of this extirpated species would align with this restoration mandate and the National Park Service’s mission to preserve and protect endangered species.




The Mexican wolf is the smallest and most genetically distinct of the gray wolf subspecies with adults weighing between 50 and 90 pounds (23 to 41 kg), averaging between 4'6" (137 cm) and 5’6" (168 cm) in total length, and with a shoulder height between 26" and 32" (66 cm and 81 cm). (USFWS 1996, iv)


Mexican wolves have mottled coats of buff, tan, rust, gray, and black. Unlike other subspecies of gray wolf, Mexican wolves do not have solid black or white coats.


The breeding season for Mexican wolves is in February. After a two-month pregnancy, females birth four to six pups in April or early May. When in a pack setting, the alpha pair tend to be the only ones breeding.

Mexican wolves did reproduce with their northern cousins and other gray wolf subspecies, with evidence showing Mexican wolf genetic dispersion as far northeast as Nebraska.




Historically, scientists speculate that prey species comprised of Coues white-tailed deer, Merriam’s elk, and small mammals.

A modern study in the Blue Range Wolf Recovery Area in Arizona and New Mexico found that Rocky Mountain elk were “the most frequent food item in both Mexican wolf and coyote scats.” For wolves, vegetation and wild rabbits were the second and third most common sources. (Carrera 2008, 377-8)

Another study focused on summer diet. Again, elk comprised 80.3% of the diet of Mexican wolves. (Merkle 2009, 482) Neither of these studies specified a preference for adults or calves.

Even though elk are the primary food source, wolf predation of elk in the Jemez Mountains would not be significantly impacted. Elk in the Jemez Mountains are very numerous and they are currently hunted by mountain lions, black bears, coyotes, and humans. There might be a temporal shift of when elk use different habitats. Elk are very good at detecting predators and changing their habits to avoid locations where predators may be active and the time of day of high activity.


Brief History of Wolves

Gray wolves once ranged all across North America. What are considered subspecies specialized in different regions. In the Desert Southwest, the Mexican wolf subspecies of gray wolf emerged. Historically, Mexican wolves and northern gray wolves were both in Valles Caldera and the Jemez Mountains.

Unfortunately, canids—wolves, coyotes, and foxes—have a bad reputation as dangerous even though it is contrary to evidence. The first hunting bounties passed in 1645 in the Massachusetts Bay Colony. City, county, territorial, and state governments continued to issue bounties on wolves well into the 19th-century. Organized wolf hunts and individual ranchers targeting wolves were also common.

There was a tragic turning point in 1915, when Congress created the Predatory Animal and Rodent Control Service. Using mostly strychnine—a chemical poison—but also traps and expert hunters for particularly tricky animals, federal agents—including NPS rangers—oversaw the near-eradication of wolves in the United States, with just a few packs escaping the slaughter in northern Minnesota and Michigan. (Coleman 2004, 5)

Wolves in northern New Mexico were not spared this eradication effort. The last Mexican wolf documented in the private ranch that is today Valles Caldera National Preserve was killed by ranch hand John Davenport in 1932 as part of this larger predator extermination movement. The Predatory Animal and Rodent Control Service reported the last animal killed in New Mexico in 1960, although this last date is disputed, with some sources saying 1942 and others 1970. (USFWS 1996, 1-6) U.S. Fish and Wildlife Service declared the Mexican wolf subspecies extinct in the United States in 1970 after two Mexican wolves were killed near Alpine, Texas. (Heffelfinger 2017, 773)

The U.S. listed Mexican wolves as an endangered subspecies on April 28, 1976, and gray wolves on March 9, 1978. (USFWS 1998, 1752) Fearing the collapse of the species, the U.S. Fish and Wildlife Service and Mexican Dirección General de la Fauna Silvestre created the Wolf Recovery Program in 1982. By the mid-1990s, the only surviving Mexican wolves existed in captivity, with a breeding program led by the U.S. Fish and Wildlife Service in Albuquerque, New Mexico. (USFWS 1996, Chapter 1-1)

Seeking the recovery of the species, the U.S. Fish and Wildlife Service decided to reintroduce the Mexican wolf to the Apache and Gila National Forests in Arizona and New Mexico as a “nonessential experimental population.” This designation gave managers greater flexibility under the terms of the Endangered Species Act, but when Mexican wolves move out of the designated area, they are subject to the protections of the act. (USFWS 1998, 1752) The first Mexican wolves back into the wild in the Blue Range Wolf Recovery Area in 1998.

On November 11, 2023, the female Mexican wolf, Asha or F2754, was the first Mexican wolf to roam Valles Caldera's landscape since 1932—a span of more than 90 years. While wandering outside of the park, Asha was captured by the New Mexico Game and Fish on December 9, 2023, and returned to the Sevilleta Wolf Management Facility.


Mexican Wolf Recovery Efforts

The U.S. Fish and Wildlife Service leads the recovery efforts in collaboration with the states of New Mexico and Arizona.

You can learn more about the recovery program at the U.S. Fish and Wildlife Service's Conserving the Mexican Wolf web page.


News About Mexican Wolves

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    Anschuetz, Kurt F. and Thomas Merlan. 2007. More Than a Scenic Mountain Landscape: Valles Caldera National Preserve Land Use History. Fort Collins: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station.

    Carrera, Rogelio, Warren Ballard, Philip Gipson, Brian T. Kelly, Paul R. Krausman, Mark C. Wallace, Carols Villalobos, and David B. Webster. 2008. “Comparison of Mexican Wolf and Coyote Diets in Arizona and New Mexico.” The Journal of Wildlife Management 72, no. 2 (February). 377-78.

    Chambers, Steven M., Steven R. Fain, and Bud & Amaral Fazio. 2012. “An Account of the Taxonomy of North American Wolves from Morphological and Genetic Analysis.” North American Fauna 77, no. 77 (October): 1-67.

    Coleman, Jon. 2002. Viscious: Wolves and Men in America. New Haven: Yale University Press.

    Dean, Adam W. 2023. “The Environmental History of the Turku Wolf Attacks.” University Research Center presentation, University of Lynchburg, Lynchburg, VA, March 27, 2023.

    Flores, Dan. 2017. Coyote America: A Natural and Supernatural History. New York: Basic Books.

    Heffelfinger, James R., Ronald M. Nowak, and David Paetkau. 2017. “Clarifying Historical Range to Aid Recovery of the Mexican Wolf.” The Journal of Wildlife Management 81, no. 5. 766-777.

    Merkle, Jerod A. , Paul R. Krausman, Dan W. Stark, John K. Oakleaf, and Warren B. Ballard. 2009. “Summer Diet of the Mexican Gray Wolf.” The Southwestern Naturalist 54, no. 4 (December). 482.

    Raynor, Jennifer L., Corbett A. Grainger, and Dominic P. Parker. 2021. “Wolves make roadways safer, generating larger economic returns to predator conservation.” PNAS 118, no. 22 (March). 4.

    Reed, Janet E., Warren B. Ballard, Philip S. Gipson, Brian T. Kelly, Paul Krausman, Mark C. Wallace, and David B. Wester. 2006. “Diets of Free-Ranging Mexican Gray Wolves in Arizona and New Mexico.” Wildlife Society Bulletin 34, no. 4 (November). 1129.

    Reiger, John F. 2011. American Sportsmen and the Origins of Conservation. Corvallis: Oregon State University Press.

    Smith, Douglas W., Daniel R. Stahler, Daniel R. MacNulty, and Lee W. Whittlesey. 2020. Yellowstone Wolves: Science and Discovery in the World’s First National Park. Chicago: University of Chicago Press.

    Steinberg, Ted. 2002. Down to Earth: Nature’s Role in American History. New York: Oxford University Press.

    U.S. Fish and Wildlife Service. 2023. "Conserving the Mexican Wolf." Last accessed December 19, 2023.

    U.S. Fish and Wildlife Service. 1998. “Establishment of a Nonessential Experimental Population of the Mexican Gray Wolf in Arizona and New Mexico.” Federal Register 63, no. 7 (January). 1752-1771.

    U.S. Fish and Wildlife Service. 1996. Reintroduction of the Mexican Wolf within Its Historic Range in the Southwestern United States. Final Environmental Impact Statement. Washington, D.C.: U.S. Department of the Interior.

    Wright, Gregory J., Rolf O. Peterson, Douglas W. Smith, and Thomas O. Lemke. 2006. “Selection of Northern Yellowstone Elk.” The Journal of Wildlife Management 70, no. 4 (August). 1070.

    Last updated: December 27, 2023

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