Wolf reintroduction involves the reintroduction of a portion of grey wolves in areas where native wolves have been extirpated. This is only considered though if suitable land and resources can be found for the target species. In the case of wolves this can be rather tricky as they need fairly large amounts of land to roam. This process often comes with conflict from parties who may oppose wolf reintroduction, and efforts are often large public issues. Over the past thirty years there have been several wolf reintroduction efforts across the world in areas like Yellowstone, the Southern USA, Appalachia, Mexico, and throughout different parts of Europe. More than 30 subspecies of Canis lupus have been recognized, and grey wolves, as colloquially understood, comprise non domestic/feral subspecies.
United States
Arizona and New Mexico
The five last known wild Mexican gray wolves were captured in 1980 in accordance with an agreement between the United States and Mexico intended to save the critically endangered subspecies. Between 1982 and 1998, a comprehensive captive-breeding program brought Mexican wolves back from the brink of extinction. Over 300 captive Mexican wolves were part of the recovery program.
The ultimate goal for these wolves is to reintroduce them to areas of their former range. In March 1998, this reintroduction campaign began with the releasing of three packs into the Apache-Sitgreaves National Forest in Arizona, and 11 wolves into the Blue Range Wilderness Area of New Mexico. By 2014, as many as 100 wild Mexican wolves were in Arizona and New Mexico. The final goal for Mexican wolf recovery is a wild, self-sustaining population of at least 300 individuals. In 2021, 186 wolves were counted in the annual survey, of which 114 wolves were spotted in New Mexico and the other 72 in Arizona. This shows a steady growth throughout the last 5 years.
Distribution and population , there were at least 319 wild Mexican wolves in the United States: 176 in New Mexico and 143 in Arizona. This represents 10 years of consecutive population growth. The total captive Mexican wolf population is 380 individuals, across over 60 facilities.
Colorado
Wolves traversed a Rocky Mountain pathway from Canada to Mexico until the 1940s. They are seen by wildlife experts as essential to the native balance of species, species interactions, and ecosystem health. But are seen as a problem species by many as they have a reputation of attacking and hunting livestock. Colorado Parks and Wildlife (CPW) created a multidisciplinary working group that drafted a wolf management plan for possible reintroduction. The Colorado Wildlife Commission approved the plan in May 2005.
Proposition 114, a ballot initiative to introduce wolves on the Western Slope by 2023, was narrowly approved by voters in November 2020. The Colorado Parks and Wildlife Commission was tasked with preparing a plan.
In late December 2023, the first wolves were released onto public land in Summit and Grand counties. The 10 wolves were translocated from Oregon. The group consisted of two adult male, two juvenile males, and six juvenile females. However, since then several of those wolves have died, mostly from illegal shootings. Because of this CPW translocated another fifteen wolves from British Columbia, Canada in 2025. There continues to be quite a lot of discourse between parties over the Colorado wolf reintroduction, as those who are against it still feel like the wolves pose a threat to the agricultural business, and those who support it push for even more protective legislature around the wolves.
Northern Rocky Mountains
Grey wolf packs were reintroduced to Yellowstone National Park and Idaho starting in 1995. These wolves were considered as “experimental, nonessential” populations per article 10(j) of the Endangered Species Act (ESA). Such classification gave government officials greater leeway in managing wolves to protect livestock, which was considered one of a series of compromises wolf reintroduction proponents made with concerned local ranchers.
Local industry and environmental groups battled for decades over the Yellowstone and Idaho wolf reintroduction effort. The idea of wolf reintroduction was first brought to Congress in 1966 by biologists who were concerned with the critically high elk populations in Yellowstone and the ecological damages to the land from excessively large herds. Officially, 1926 was when the last wolves were killed within Yellowstone's boundaries. When the wolves were eradicated and hunting eliminated, the elk population boomed. Over the succeeding decades, elk populations grew so large that they unbalanced the local ecosystem. The number of elk and other large prey animals increased to the point that they gathered in large herds along valley bottoms and meadows, overgrazing new-growth vegetation. Because of overgrazing, deciduous woody plant species, such as upland aspen and riparian cottonwood, became seriously diminished. So, because the keystone predators, the wolves, had been removed from the Yellowstone-Idaho ecosystem, the ecosystem changed. This change affected other species as well. Coyotes filled in the niche left by wolves, but could not control the large ungulate populations. Booming coyote numbers, furthermore, also had a negative effect on other species, particularly the red fox, pronghorn, and domestic sheep. Ranchers, though, remained steadfastly opposed to reintroducing a species of animal that they considered to be analogous to a plague, citing the hardships that would ensue with the potential loss of stock caused by wolves.
The government, which was charged with creating, implementing, and enforcing a compromise, struggled for over two decades to find middle ground. A wolf recovery team was appointed in 1974, and the first official recovery plan was released for public comment in 1982. General public apprehension regarding wolf recovery forced the U.S. Fish and Wildlife Service to revise their plan to implement more control for local and state governments, so a second recovery plan was released for public comment in 1985. That same year, a poll conducted at Yellowstone National Park showed that 74% of visitors thought wolves would improve the park, while 60% favored reintroducing them. The preparation of an environmental impact statement (EIS), the last critical step before reintroduction could be approved, was halted when Congress insisted that further research be done before an EIS was to be funded.
In 1987, in an effort to shift the burden of financial responsibility from ranchers to the proponents of wolf reintroduction, Defenders of Wildlife set up a "wolf compensation fund" that would use donations to pay ranchers market value for any stock that was lost to wolf depredation. That same year, a final recovery plan was released. Following a long period of research, public education, and public commenting, a draft EIS was released for public review in 1993, and it received over 150,000 comments from interested parties. It was finalized in May 1994, and included a clause that specified that all wolves reintroduced to the recovery zones would be classified under the "experimental, nonessential" provision of the ESA. Though the original plan called for three recovery zones – one in Idaho, another in Montana, and a final one in the greater Yellowstone area – the Montana recovery zone was eliminated from the final EIS after it had been proven that a small, but breeding population had already established itself in the northwestern part of the state. The plan stipulated that each of the three recovery areas must have 10 breeding pairs of wolves successfully rearing two or more pups for three consecutive years before the minimum recovery goals would be reached.
Two lawsuits filed in late 1994 put the recovery plan in jeopardy. While one of the lawsuits was filed by the Wyoming Farm Bureau, the other was filed by a coalition of concerned environmental groups including the Idaho Conservation League and Audubon Society. The latter group pointed to unofficial wolf sightings as proof that wolves had already migrated down to Yellowstone from the north, which, they argued, made the plan to reintroduce an experimental population in the same area unlawful. According to their argument, if wolves were already present in Yellowstone, they should rightfully be afforded full protection under the ESA, which, they reasoned, was preferable to the limited "experimental" classification that would be given to any reintroduced wolves.
Nevertheless, both cases were thrown out on January 3, 1995. Adolescent members from packs of Mackenzie Valley wolves in Alberta, Canada, were tranquilized and carted down to the recovery zones later that week, but a last-minute court order delayed the planned releases. The stay came from an appellate court in Denver, and was instigated by the Wyoming Farm Bureau. After spending an additional 36 hours in transport cages in Idaho and in their holding pens in Yellowstone, the wolves were finally released following official judicial sanction. Yellowstone's wolves stayed in acclimation pens for two more months before being released into the wild. Idaho's wolves, conversely, were given a hard (or immediate) release. Sixty-six wolves were released to the two areas in this manner in January 1995 and January 1996.
The 2005 estimates of wolf populations in the two recovery zones reflect the success the species has had in both areas: Greater Yellowstone area: 325 Central Idaho: 565
These numbers, added with the estimated number of wolves in northwestern Montana (130), puts the total number of wolves in the Northern Rocky Mountains recovery area at over 1000 individuals. This includes about 134 packs (two or more wolves traveling together) and 71 breeding pairs (male and female that successfully rear a litter of at least two until Dec. 31). The recovery goal for the area was revised to 30 breeding pairs total, and this number has been surpassed for some time.
Current wolf population statistics can be found at Gray Wolf (Canis lupus) | U.S. Fish & Wildlife Service