B.C.'s wolverines are expanding their territory, according to a study published Monday in The Canadian Field-Naturalist.

Department of Fisheries and Oceans biologist Tom Shardlow, who authored the report, says at least two wolverines have taken up residence on Princess Royal Island, 130 kilometres south of Kitimat, in B.C.'s Great Bear Rainforest.

Shardlow says it's the first proven sighting of a wolverine in the area. 

B.C. has 3,000 to 4,000 wolverines, but until now, most have been living in snowy habitats at higher elevations in the province's interior. 

"It's an oddity, It's the first time anything has been published that indicates wolverines occupy these islands."

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Wolverines in B.C. traditionally live in snowy habitats at higher elevations

Wolverines are about the same weight as a mid-sized dog, but the largest land-inhabiting member of the weasel family has been known to kill caribou up to 10 times its size, according to the Columbia Mountains Institute of Applied Ecology. They are scavengers who live mainly by feeding on dead animals.

Sightings of the animal on the coast are rare and while there have been anecdotal reports of them being spotted on coastal islands, Shardlow says none have been verified and published until now.

New location brings changes in eating habits

The study also marks the first time the animal has been documented eating salmon.

"Wolverines found in the coastal watersheds of British Columbia would be expected to encounter moribund salmon from spawning runs in many of the streams. However, there are no records of salmon consumption by this scavenger."

Many other animals eat fish on the island, but Shardlow says he didn't expect wolverines would.

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The study showed at least one wolverine had changed its diet since moving to the coast and is now eating dead salmon

"The kind of species we expect to see using salmon are all there, but there was one nobody ever expected to see — and that's a wolverine."

Wolverines typically live off the carcasses of wild game such as deer, but hair samples indicate one of the wolverines documented in the study had marine protein in its diet.

Shardlow made the discovery by creating cage-like structures with bait inside. Cameras were set up at each of the stations so the animals could be identified.

When the wolverines took the bait, their fur was snagged on the barbs of the cage. The biologist removed the hair, tested the samples in a lab and found the carbon-13 and nitrogen-15 isotopes associated with marine protein.

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Since the wolverine inhabits an area close to a watershed filled with salmon, Shardlow concluded that was likely the source of its marine protein. 

Shardlow says his discovery adds yet another animal to the long list of those that depend on the province's salmon for survival placing even more importance on the need to preserve the fish stock.

with files from the Canadian Press