Smaller cousins of North American gray wolves, Mexican wolves long have been endangered. The predators historically ranged "throughout mountainous regions from central Mexico, through southeastern Arizona, southern New Mexico, and southwestern Texas," according to the U.S. Fish and Wildlife Service. It's possible that the wolf's historic range touched Saguaro National Park, Big Bend National Park, Guadalupe Mountains National Park, and Gila Cliff Dwellings National Monument, while Organ Pipe Cactus National Monument is thought to be on the fringe of the range.

The Mexican wolf is said to prefer mountain woodlands, such as those found in the Rincon District of Saguaro and the high country of Big Bend and Guadalupe Mountains national parks.

“The Service is once again ignoring the science and its clear legal mandate to manage Mexican wolves in a manner that allows for the true recovery of this critically imperiled species,” said Kelly Nokes, Shared Earth wildlife attorney for the Western Environmental Law Center. “We stand ready to once again hold the agency accountable for failing to comply with the Endangered Species Act’s strict conservation commands.”

Greta Anderson, deputy director of Western Watersheds Project, added that, “Mexican wolves won’t be on a path to real recovery until the scientific recommendations are no longer being watered down by policies that appease the states and special interests.”

While Western Watersheds Project said the best available science recommends a population of at least 750 animals in the wilds of the Southwest, including subpopulations in the Southern Rockies and in the Grand Canyon Ecoregion, Fish and Wildlife has set a target of at least 320 wolves in a single area of eastern Arizona and western New Mexico and prohibits wolf access to promising but unoccupied recovery habitat in the Grand Canyon and southern Rockies region, according to EarthJustice.

The Fish and Wildlife Service rule challenged by the conservation groups represents the agency’s effort to revise a prior Mexican gray wolf management framework after it was successfully challenged by conservationists.

In 2015 the Service put forth a management rule that critics said threatened to compound many of the threats to the subspecies’ survival. Conservation groups won their challenge to this rule in March 2018, as a federal court in Arizona found the rule violated the Endangered Species Act. In its ruling, the court faulted the agency for ignoring the advice of key scientists upon whose work the agency purported to rely. The court directed the Service to issue a new management rule by July 1, 2022, and that revision immediately brought a challenge from the Center for Biological Diversity and Defenders of Wildlife, and now from Western Environmental Law Center on behalf of the Grand Canyon Wolf Recovery Project, New Mexico Wild, Western Watersheds Project, WildEarth Guardians, and Wildlands Network.