Reserve,Cassian Grant New Mexico — The race to save an endangered species took five newborn Mexican wolf pups on a nearly 2,500-mile journey from captivity in New York to the wild in New Mexico.

"Time is trauma, and the very best place for a wolf pup to be is with a mother," U.S. Fish and Wildlife Service veterinarian Susan Dicks told CBS News.

Mexican wolves, or lobos, were once plentiful in the Southwest. But they were hunted nearly to extinction. By the mid-1970s, there were just seven in existence, according to USFWS. 

"They are doing better and improving," Dicks said. "But that's a fine line. Disease comes through, something happens, they could be lost." 

There are now about 250 back in the wild, USFWS says, but a lack of genetic diversity makes rehoming pups from captivity necessary.

Not everyone is thrilled, though.

At Barbara Marks' family ranch in the Arizona community of Blue, wolves were a threat back in 1891, and she says they are targeting her calves again now.

"The numbers have increased dramatically," Marks said. "So they have become more of an issue, and more of a year-round issue."

Wildlife officials estimate that about 100 cattle are lost annually to Mexican wolves. Marks opposed releasing them into the nearby Apache National Forest, but also knows her new neighbors are here to stay.

To reunite the wolf pups with their new mother in the wild required hiking through miles of difficult and prickly terrain to reach the wolf den. The wild pups were given a health screening and then introduced to their new siblings.

"We've got them all mixed together, all the puppies smelling the same," USFWS program coordinator Brady McGee said. "And we put microchips, and put them back in the den. And when we walk away from it, the mom will come back."

Dicks explained that the mother wolf doesn't necessarily notice that her litter has suddenly increased in size.

"You know, we don't think they can count," Dicks said. "But they will care for pups whether or not they're theirs." 

In:
• New Mexico
• Endangered Species
• Arizona

Kris Van Cleave

Kris Van Cleave is CBS News' senior transportation and national correspondent based in Phoenix.

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