Mexican wildlife managers release 2 pairs of wolves

In this undated file photo provided by the U.S. Fish and Wildlife Service, a Mexican gray wolf leaves cover at the Sevilleta National Wildlife Refuge, Socorro County, N.M. Wildlife managers in the United States say their counterparts in Mexico have released two pairs of endangered Mexican gray wolves south of the U.S. border as part of an ongoing reintroduction effort. (Jim Clark/U.S. Fish and Wildlife Service via AP, File)