Killing Wolves to Keep Them From Killing Sheep Is Backfiring

A new study finds that surviving wolves are more likely to prey on livestock.

(Photo: David Tipling/Getty Images)

Dec 4, 2014· 1 MIN READ
Taylor Hill is an associate editor at TakePart covering environment and wildlife.

Call it revenge killings.

Or call it how science sees it. Either way, the idea that shooting wolves keeps them from preying on livestock looks like it’s going up in flames.

That’s because a new study published in the journal PLOS One found that shooting and trapping gray wolves to control livestock predation leads to more dead sheep and cattle the following year, not fewer.

Armed with 25 years of data from the U.S. Fish and Wildlife Service, Washington State University researchers reviewed traditional wolf management efforts.

“I had no idea what the results were going to be, positive or negative,” Rob Wielgus, a WSU wildlife biologist and coauthor of the study, said in a statement. “I said, ‘Let’s take a look at it and see what happened.’ I was surprised that there was a big effect.”

A billboard paid for by Washington Residents Against Wolves highlights the anti-wolf campain many ranchers in the state support. (Photo: Courtesy

For each wolf killed, the researchers found that the odds of death by wolf predation rose 4 percent for sheep and 5 to 6 percent for cattle.

But why do wolf predation incidents increase if there are fewer wolves in an area?

Wielgus and fellow researcher Kaylie Peebles think killing individual wolves—especially alpha males—disrupts the breeding structure of the pack and can end up creating more breeding pairs, as younger males split off and form their own families.

When there are more pairs of wolves with young pups, they are less likely to venture out and hunt than to prey on easy targets like sheep and cattle.

“Lethal control of individual depredating wolves may sometimes be necessary to stop depredations in the near-term, but we recommend that non-lethal alternatives also be considered,” the study states.

The battle between wolves and ranchers has been going on since gray wolves were listed as an endangered species in 1974. The reintroduction of wolves in the Northern Rockies in the 1990s sparked a recovery of the species. Wolves expanded from Wyoming, Montana, and Idaho into Washington, Oregon, and even California. But as that range grew, wildlife agencies began to kill wolves suspected of preying on livestock.

The government removed gray wolves from the endangered species list in 2012, and hunters have already exterminated more than a third of the 1,600 wolves thought to live in Wyoming, Montana, and Idaho.

The current killing rate “is unsustainable and cannot be carried out indefinitely if federal relisting of wolves is to be avoided,” according to the study.

In Washington state, the study was met by disapproval by the pro-livestock group Washington Residents Against Wolves. Jamie Henneman, a spokesperson for the organization, told The New York Times that the study was “not clean science.”

“They just want to get rid of wolves,” Wiegus told the Times regarding Henneman’s criticism. “Livestock lobbyists are pretty much vehemently opposed to my research, but in terms of hard science, it stood the test.”