New study sheds light on relationship between wolves and moose population

The mystery behind Minnesota and northwestern Ontario's diminishing moose population has been an ongoing discussion for the last two decades.

• Wolves could stem explosion of Isle Royale moose herd, says Michigan professor

• Don't blame wolves for moose population decline, Animal Alliance says

In January a research scientist with the U.S. Geologic Survey, David Mech, published a paper online in the Wildlife Society Bulletin on his study examining the interaction and relationship between wolves and moose calves.

As the population of wolves in the area goes up Mech said he noticed that the number of moose goes down.

"We looked at the relationship between wolf numbers ... in a given year ... and the number of moose that year and the following year [to] try and see if there was some relationship between those numbers," Mech told CBC Thunder Bay's outdoor columnist Gord Ellis. 

Based on those numbers, Mech said he was able to discover "some evidence that wolves are having [an] influence on the moose population."

Older moose more vulnerable than moose calves

By radio collaring wolves every summer, Mech said he and his team of scientists were able to count and track the animals from the air, while the moose are counted by the Minnesota DNR each winter.

He said while the wolves take both the older and younger moose, he noticed that the majority of the older moose that were killed by wolves had something debilitating them, thus making them more vulnerable as prey.

"With the older moose ... either they're real old when the wolves take them or there's something else debilitating them —some parasite or some malnutrition — like a predisposing condition that allows the wolves to kill them," Mech explained. 

He said because of the lack of experience and size, moose calves are also pretty vulnerable to wolves regardless of health.

"We have not yet, nor has anyone, been able to examine enough of those wolf-killed-moose-calves to determine for sure that they were all real healthy ... that's information we still don't have and would like to get," Mech added.

He said the up and down relationship between the moose and wolf population is a natural occurrence.

• Wolves nearly gone from Michigan's Isle Royale National Park

• Isle Royale wolf population increases to two

"There is really no definite human cause to these moose declines that we've been able to see," Mech said, "and if you look at what's happened on Isle Royal on Lake Superior ... it's pretty clear that these kinds of interactions are pretty natural."