By Susan Montoya Bryan / The Associated Press

Wildlife managers are running out of options when it comes to helping Mexican gray wolves overcome hurdles that have thwarted reintroduction into their historic range in the Southwest.

Harassment and rubber bullets haven't worked, so they're trying something new – a food therapy that has the potential to make the wolves queasy enough to never want anything to do with cattle again.

As in people, the memories associated with eating a bad meal are rooted in the brain stem, triggered any time associated sights and smells pulse their way through the nervous system.

Wildlife managers are trying to tap into that physiological response in the wolves, hoping that feeding them beef laced with an odorless and tasteless medication will make them ill enough to kill their appetite for livestock.

Cattle depredations throughout southwestern New Mexico and southeastern Arizona have served as an Achilles' heel for the federal government's efforts to return the wolves.

Conditioned taste aversion – the technical term for what amounts to a simple reaction – is not a magic bullet for boosting the recovery of the Mexican wolf, but some biologists see it as one of few options remaining for getting the program back on track after nearly 14 years of stumbling.

"Just the very fact that the U.S. Fish and Wildlife Service is trying something new ought to send the message that they really are seriously concerned about the ranchers' concerns," said Dan Moriarty, a professor and chairman of the psychological sciences department at the University of San Diego.

After four decades and tens of millions of dollars, the federal government was recently able to remove the animals from the endangered species list in several states.

The case is much different in the Southwest, where the population of the Mexican wolf – a subspecies of the gray wolf – continues to be about 50 despite more than a decade of work. Biologists had hoped to have more than 100 wolves in the wild by 2006.

About 90 wolves and some dependent pups have been removed, in some cases lethally, from the wild since the program began because of livestock problems. In the last year, monthly reports show wildlife managers investigated four dozen depredations in Arizona and New Mexico. They determined that wolves were involved in half of the cases.

Biologists working at a captive breeding center at the Sevilleta National Wildlife Refuge in south-central New Mexico treated six wolves last April and two more in October. The animals were fed baits made up of beef, cow hide and an odorless, tasteless deworming medication that makes the wolves queasy.

Fish and Wildlife Service biologist Susan Dicks said the initial tests appear to be successful, with the wolves not wanting anything to do with the beef baits after their first serving.

"We're learning as we go, but so far we have seen some good aversions produced," Dicks said. "Again, it's impossible to say yet whether this translates to a livestock animal running around on the hoof."

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