CODY - Ongoing research on wolves in Yellowstone National Park continues to yield new information about how the animals hunt and how their pack dynamics differ from those of packs in the rest of North America.

"How wolves function in this tri-state area is very different from how they function in the far north of Canada," said Doug Smith, the biologist in charge of the Yellowstone Wolf Project.

Smith spoke Thursday to a capacity crowd at the Buffalo Bill Historical Center, presenting highlights of findings included in the project's 2008 annual report.

Northern Canada has about 55,000 wolves and Alaska has about 10,000, so regional populations there are easily replenished by dispersing packs from elsewhere, despite heavy hunting in particular areas, he said.

"In the north, you have an ocean of wolves. The whole area is one big wolf population" surrounded by isolated pockets of people, Smith said.

"What we have here is an ocean of humanity with a couple of small areas of wolf survival, so it's a reverse dynamic," he said, adding that it is important to understand the difference. Scientists have largely modeled projections about Yellowstone wolf populations on lessons learned from wolves in the north.

But Yellowstone is special because wolves inside the park are virtually free of mortality from human causes, while 80 percent of wolves across the rest of North America are killed through hunting or by other human measures.

Consequently, there tend to be greater numbers of older wolves in Yellowstone packs, making for more experienced hunters than in nearby packs outside the park, he said.

"Yearlings have the highest rates of participation but the lowest success" in hunts, he said.

Biologists are learning more about the roles in hunting of different wolves within a pack's social structure.

"Females, with their sleek, slim, fast body types, are typically out front, picking out which elk to attack, along with the younger males," he said.

"The female will grab the elk, and at the end of the hunt, the big male catches up. These big males are important in the takedown. They are the best killers in the pack. But they're not at the forefront of the hunt," Smith said.

Researchers have found that packs with at least one large male tend to do much better in hunting elk than packs with none. Multiple large males are important for packs hunting bison or moose.

Wolves also tend to fare better in hunting elk during severe winters and in deeper snow, when their prey is weaker and has greater difficulty escaping, he said.

Smith said that fall "is the hardest time of the year to be a wolf" because elk are well-fed and in good shape, making them harder to catch.

Last year was a tough year for Yellowstone's wolves for a number of reasons, including disease, with distemper believed to have taken a heavy toll on pups.

Every one of the 25 new pups in the Leopold pack died, and the pack's alpha male was killed by a wolf in a neighboring pack. The result was the end of the pack.

"The Leopold pack completely crumbled after 12 years," he said.

A 40 percent drop last year in wolves in the northern part of the park was due to a number of reasons, including disease, inter-pack killings, some food shortages and a high density of wolves and other carnivores there, Smith said.

"We have probably hit a high point for wolves in that northern range already. I think, long term, we have begun to decline," he said, adding that it may take a decade or longer for wolf and elk numbers in the area to stabilize.

"In the long term, I would expect half as many wolves on the northern range as we have now," Smith said.

Contact Ruffin Prevost at rprevost@billingsgazette.com or 307-527-7250.