For years, cattle ranchers and wool growers have fretted over wolves that kill dozens of cows and sheep each year. But the steepest price may be the declining weight of livestock terrified by the howls and footsteps of the stalking predators.
Currently, calves fetch $1.45 per pound on the market. So if wolves cause just a few lost pounds on each head of cattle, that quickly mounts into big losses, said Lloyd Knight, the executive director of the Idaho Cattle Association.
''When the cows are scared, they bunch together, they don't spread out like they're used to. They don't eat and drink - you can just tell they're losing weight,'' he said. ''The loss of weight from the whole herd could cost far more than the depredation of a few calves. It's something we've been afraid of since the reintroduction program began.''
Federal wildlife officials reintroduced endangered gray wolves into Yellowstone National Park and the central Idaho mountains in 1995, and the predators have thrived. A decade later, ranchers say, wolf packs are roaming further afield, their presence wreaking as much havoc as their bite.
The Idaho Office of Species Conservation, an agency that compensates ranchers for wolf-related losses through an annual $100,000 appropriation from Congress, has agreed to pay any rancher who can demonstrate weight loss through record-keeping. ''I've heard the theory before and it makes sense,'' said Jeff Allen, the office's policy adviser. ''It's something this office has agreed to fund.''
The conservation group Defenders of Wildlife has spent hundreds of thousands of dollars to cushion the fiscal effect since reintroduction began, offering to recoup ranchers for the confirmed depredation, or killing, of livestock.
But Amaroq Weiss, a Defenders wolf specialist in Ashland, Ore., said careful scientific research is needed to determine the extent and validity of ranchers' weight-loss claims. Until then, the wildlife group could not reimburse ranchers for lanky animals.
''We're not inclined to compensate people for perceived weight loss, until there is research to show it is occurring, or if it's even probable that it's occurring,'' Weiss said. ''We certainly welcome the research.''
Proving that animal weight loss stems from wolf jitters and not some other factor in the vast matrix of variables that includes rangeland health, migration patterns and forage production, is difficult if not impossible, said Curt Mack, a wildlife biologist with the Nez Perce Indian tribe, which also has a hand in Idaho's wolf oversight.
The phenomenon likely exists, but its extent is ''intangible and unquantifiable,'' Mack said.
He also cast doubt on the idea that sheep and cattle live in a permanent state of panic, pointing to research that shows some prey animals, such as elk and cattle, exhibit heightened recognition when wolves are hunting and relax their guard when the predators are merely roaming.
Although accounts remain anecdotal, nobody is more qualified to assess the physiology of their animals than the ranchers, said Todd Grimm, the acting director of the Idaho branch of the U.S. Department of Agriculture's Wildlife Services Division, which traps and shoots wolves known to prey on livestock.
''Most of these guys have had grazing allotments for so long, they have a real long history of what a calf should weigh when it comes off the mountain,'' he said. ''And, they've got a lot of facts and figures to go along with that.'' Stan Boyd, executive director of the Idaho Wool Growers Association, said most of his members are reporting lamb weights between 2 and 8 pounds below the prior three-year average.
Nerves are to blame, he said. ''They're just being dogged out there,'' he said. ''So there's safety in numbers. A band of lambs will crowd together and just quit eating.''
On the Net:
Idaho Wool Growers Association: http://www.idahowool.org/
Defenders of Wildlife: http://www.defenders.org/