PULLMAN, Wash., Dec. 4 (UPI) -- The frequent fights that boil up over the protection of wild predators routinely feature the same interested parties -- conservationists and animals rights activists one on side, ranchers on the other.
Understandably, ranchers are consistently concerned about their ability to protect their herds -- their assets. But now, new research may weaken their bargaining position, as recent scientific evidence suggests killing wolves does not reduce the frequency of livestock attacks.
Researchers at the Washington State University arrived at their findings after analyzing 25 years of lethal control data from U.S. Fish and Wildlife Service. The data on wolf killings in Montana, Wyoming and Idaho showed that killing a single wolf actually increased the chance of livestock attacks the following year.
One dead wolf increased odds of depredations four percent for sheep herds, and five to six percent for cattle. If 20 wolves were shot or trapped the year prior, livestock deaths doubled.
"I had no idea what the results were going to be, positive or negative," Rob Wielgus, a wildlife biologist at Washington State University, said in a press release. "I said, 'Let's take a look at it and see what happened.' I was surprised that there was a big effect."
Wielgus, who conducted the research with the help of data analyst Kaylie Peebles, says that killing wolves likely disrupts the social order of the pack. An older mating pair will keep younger, less mature wolves from coupling and starting a family. But should one or both of two mature mating wolves be killed, younger pairs will form. Starting a family limits a wolf's ability to hunt, and increases the likelihood that a wolf will be forced to seek out easy prey like cattle and sheep.
Wielgus encourages ranchers to use more effective non-lethal strategies like guard dogs, range guards on horseback, flags and spotlights.
"The only way you're going to completely eliminate livestock depredations is to get rid of all the wolves," Wielgus said, "and society has told us that that's not going to happen."
The study was published this week in the journal PLOS ONE.