An endangered Mexican wolf has crossed into Mexico from New Mexico for the first time in decades, but wildlife experts worry it may be the last such crossing due to ongoing border wall construction.
The radio-collared male wolf entered Chihuahua, Mexico, from a remote section of the New Mexico Bootheel last week, confirmed Aislinn Maestas, a U.S. Fish and Wildlife Service spokesperson. The agency monitors this smallest and most threatened subspecies of North American gray wolf, known in Spanish as “lobo.”
These wolves once thrived throughout the American Southwest and Mexico but nearly vanished in the 1970s after government agencies and ranchers systematically killed them, claiming the animals posed a threat to cattle and other livestock.
For thousands of years, these wolves have wandered the Bootheel’s varied landscape of grasslands, desert terrain, and forested mountains, using ancient migration paths to hunt for food and find mates across what is now the U.S.-Mexico border.
Both the Trump and Biden administrations constructed steel border barriers extending westward through New Mexico as part of efforts to combat human and drug smuggling.
The ongoing construction of walls measuring 18 to 30 feet tall in this region could make last week’s border crossing the final one ever recorded for this species, according to conservationist Michael Robinson.
Such isolation would worsen the wolves’ existing inbreeding crisis, which has already resulted in higher puppy mortality rates, cancer cases, and birth abnormalities.
“Sealing off the Bootheel would isolate wolves and other rare mammals like jaguars and ultimately make them all less likely to survive,” said Robinson, who serves as a senior conservation advocate at the Center for Biological Diversity.
The Department of Homeland Security and U.S. Customs and Border Protection, the agencies overseeing border barrier construction, have not yet responded to requests for comment.
Environmental organizations and some federal wildlife officials have expressed concerns that expanding border walls will break up natural habitats and interrupt animal migration patterns in areas including Texas’s Big Bend region, Arizona’s San Rafael Valley, and California’s Otay Wilderness. Homeland Security has invoked special legal powers to bypass environmental regulations, prompting legal challenges to the barriers.
While administrations from both political parties have recognized environmental concerns, they maintain the barriers are essential for national security. Officials have added some protective measures, including ground-level openings designed for smaller creatures like reptiles and rodents.
For Mexican wolves specifically, breeding between animals from both sides of the border could help address critically low genetic diversity, explained Cyndi Tuell, who directs Arizona and New Mexico operations for Western Watersheds Project, a conservation organization.
Every Mexican wolf alive today descends from just seven wolves that were successfully bred after capture as part of a joint U.S.-Mexico breeding initiative launched in the late 1970s.
Current population estimates show at least 319 wild Mexican wolves living in the United States, approximately 36 in Mexico, and roughly 380 in captive breeding facilities, according to USFWS and conservation organizations.
