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Stress affects wolves in hunting grounds, and it may alter their evolution: study

A grey wolf is shown in a March 18, 2008, photo provided by the U.S. Fish and Wildlife Service.

AP/U.S. Fish and Wildlife Service/The Canadian Press

Wolves in areas where the animals are heavily hunted have higher stress and reproductive hormones compared with those under lower hunting pressure, suggests a new study involving scientists from British Columbia, Alberta and Israel.

Researchers measured hormone levels in small tufts of wolf hair gathered in Alberta, Nunavut and the Northwest Territories.

They compared steroid hormone levels in hair of wolves living in Canada's tundra-taiga region, which has heavy rates of hunting, with those in the northern boreal forest, where hunting rates are lower.

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"The hair samples revealed that progesterone was higher in tundra-taiga wolves, possibly reflecting increased reproductive effort and social disruption in response to human-related mortality," the researchers wrote in a paper published in the journal Functional Ecology.

Researchers found "human-caused harassment" elevates stress hormones such as cortisol, alters a wolf pack's elaborate social structure and might have evolutionary consequences.

Reproductive hormones such as testosterone and progesterone may also be elevated when social conditions are unstable, the study says.

University of Calgary Prof. Marco Musiani, who co-authored the study, said the hormonal changes could result in unintended increases in reproduction rates and altered genetic structure for the animals.

"Though increased reproduction might be viewed as a positive response of wolves to population reductions, the implications on lifetime reproductive output and generational survival of offspring as compared with undisturbed populations are unknown," the study said.

The Raincoast Conservation Foundation, whose researchers participated in the study, opposes B.C.'s grey wolf management plan, which was released this spring after a review of more than 2,500 public input submissions.

B.C.'s Environment Ministry did not respond to a request for comment.

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Raincoast's executive director Chris Genovali said the study highlights the need for conservation strategies that go beyond numbers to include psychological and social effects on animals.

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