A coalition of environmental groups is threatening to sue the federal government over protections for the endangered Mexican gray wolf.
The New Mexico Wilderness Alliance, WildEarth Guardians and Friends of Animals warned the U.S. Fish and Wildlife Service of their intent to sue Tuesday.
It would mark just the latest legal challenge over changes to the wolf reintroduction program that were announced in January. Under the changes, wolves will be able to roam a greater expanse of Arizona and New Mexico and will be released at more sites.