Two wolves hanging on with abundant moose on Isle Royale

May 17, 2018
Originally published on May 18, 2018 9:39 am

The last two wolves on Isle Royale are still hanging on. 

The wolf-moose research study on the wilderness island in Lake Superior is now in its 60th year, and the report from the past year of the study is out today.

John Vucetich is a professor of wildlife ecology at Michigan Technological University. He notes the two wolves are not reproducing -- they're closely related and extremely inbred.

“The most important thing we learned is that they’re still alive. They’re hanging in there for another couple years. They’re getting old, though, they’re now seven years old and nine years old,” he says. “And you wouldn’t expect them to live for too much longer.”

The researchers estimate the island's moose population to be 1,475. 

“They’re growing rapidly. Over the past seven years, they’ve been growing at about 16% per year,” says Vucetich. “Imagine if your bank accounts grew at 16% a year, you’d be rich in a hurry. What it means on Isle Royale is that they can double in abundance in about four or five years growing at that rate.”

A freight train

He says there’s lots of food on the island right now, and that’s the only way growth like that can be sustained. Vucetich says moose love to eat balsam fir, and although there's still plenty of fir on the island, the researchers are starting to see the earliest signs of very high browse rates.

"It’s like a freight train heading straight for a wall," he says of the high moose population. "There will be a point, and it will occur suddenly, when they run out of food, and then the population would be expected at that point to collapse."

In March, the National Park Service announced its intention to introduce 20 to 30 wolves to the island. The decision still needs to be finalized, but Vucetich says if it does happen as expected, there are quite a few things to consider.

“The main issues end up being things like: what should the genetic properties of these wolves be like? Seems to be the broad consensus that they could come from anywhere in the Great Lakes region, Michigan, Minnesota, Ontario and that would be just fine, genetically," he says.

He says another important consideration is whether to introduce wolves that know how to kill moose.

"And this is a challenging one because there’s a pretty good view to think that wolves are a quick study. If they’ve never seen a moose before, if instead, they’ve only hunted say, white-tailed deer, they’ll figure it out and they’ll figure it out fast, it’s not a problem," he says.

But he says sometimes, people can also be a little overconfident about how successful reintroductions of animals will be.

"This is because reintroductions that fail, we tend to kind of forget them. We remember the successful ones. And what that means is that if you’re really sensitive to maximizing the chances of success here, you might want to consider having wolves that have experience hunting moose," he says.

Vucetich says the Park Service is consulting a panel of wolf biologists to guide the agency in these decisions.

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