Evidence shows the often-reclusive wolverine has taken up residence for the first time on an island off British Columbia’s Central Coast and the animal’s eating habits have changed along with its relocation.
The study, published Monday in The Canadian Field-Naturalist, shows that at least two wolverines inhabit Princess Royal Island, part of B.C.’s Great Bear Rainforest.
There are about 3,000 to 4,000 wolverines in B.C., but most of them are in the Interior, in snowy habitats and higher elevations, the study said.
Department of Fisheries and Oceans biologist Tom Shardlow, who authored the report, said it was the first proven sighting of a wolverine in the area.
“The main thing is it’s an oddity,” said Shardlow. “It’s the first time anything has been published that indicates wolverines occupy these islands.”
Wolverines are typically the same weight as a mid-sized dog and live mostly by scavenging from dead animals.
The largest land-inhabiting member of the weasel family, the wolverine also has a reputation for fierceness. There have been reports of wolverines killing caribou up to 10 times its size, according to the Columbia Mountains Institute of Applied Ecology.
The animal is rarely sighted on the coast, and while there have been occasional stories of the animal being spotted on the islands of the Great Bear Rainforest, none have been verified and published until now, he said.
The study also marks the first time the animal has been documented eating salmon.
“Wolverines found in 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,” the study said.
Shardlow said many other animals eat fish on the island, but he didn’t expect wolverines to do so.
“Those kind of species that we expect to see using salmon were all there,” said Shardlow. “But there was one nobody would ever expect to see – and that’s a wolverine.”
Wolverines typically live off the carcasses of wild game such as deer, but hair samples indicated that one of the wolverines documented in the study had marine protein in its diet.
To make this discovery, Shardlow created cage-like structures with bait inside. When the wolverines took the bait, their fur was snagged on the barbs of the structure.
Shardlow removed the hair, tested the samples in a lab and found carbon-13 and nitrogen-15 isotopes, which are associated with marine protein.
The wolverine inhabits an area close to a watershed filled with salmon, so that’s probably the source of its marine protein, he said.
Cameras were also set up at each of the stations so the animals could be identified.
Shardlow said 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.