PRAY (LEE) -- Those are million-dollar wolves in Yellowstone National Park, says a University of Montana economist.

Each year, people who come to Yellowstone hoping to glimpse a wolf spend around $35 million in Montana, Idaho and Wyoming, according to an intensive study of visitors by John Duffield and others.

Those dollars turn over in local communities, pushing the regional economic impact to around $70 million a year, said Duffield, who presented his findings here during the 18th annual North American Wolf Conference.

Duffield surveyed about 1,900 visitors to Yellowstone between December 2004 and February 2006. They were quizzed about why they came to the park, what they hoped to see, their opinions about wolves and other wildlife and their spending habits.

The economic impact figures are based on those in the study who said they would not be coming to Yellowstone if wolves were not present.

"Those are new dollars coming in," Duffield said.

Duffield's research found that wildlife viewing is the top attraction for Yellowstone visitors, and that the animals they most want to see are, in order, grizzly bears, wolves, mountain lions, moose and black bears.

"It kind of demonstrates our fascination with carnivores," he said.

People also may be more likely to see wolves in Yellowstone than previously thought.

Earlier estimates figured that about 20,000 visitors a year saw a wolf and that, since reintroduction of wolves in 1995 and 1996, wolves had been seen by about 153,000 people.

But Duffield, after analyzing comments in the most recent survey, said he figures about 151,000 people a year see wolves, including about 27,000 visitors in the winter.

"It's potentially reaching a lot more people than we had suspected," Duffield said.

But opinions about the presence of wolves are still split.

About 70 percent of people living in the greater Yellowstone area approve of the wolves' presence, but only 56 percent outside the area, but still in the region, feel the same, Duffield said.

And in recent years, there's been a decline in support for wolves from hunters, farmers and ranchers compared with surveys conducted in the years leading up to reintroduction.

"To me that reflects increasing polarization," Duffield said.

Some worry that attitudes toward wolves are shaped by information that's not always accurate.

At Thursday's conference, Nathan Varley, a University of Alberta researcher, and Gardiner consultant Linda Thurston addressed several "myths" associated with wolves in the northern Rocky Mountains.

One of them is the size of a wolf in Yellowstone.

"For some reason, a lot of people think they get a lot larger than they do," Thurston said, adding that a few people have mentioned wolves up to 180 pounds in the area.

But judging by more than 250 wolves in the Yellowstone area that have been weighed over the past decade, the average weight for a male wolf is 113 pounds and the average for a female is 94, according to Varley and Thurston.

There's also no evidence for claims that today's wolves, the offspring of wolves relocated from Canada, are larger than those that occupied the region before being extirpated.

A handful of recorded weights from the late 1800s and early 1900s shows that their weights were similar to today's wolves, they said.

Varley and Thurston also discussed a common complaint that elk have disappeared from areas where they once regularly roamed.

There's no doubt that elk populations have declined in recent years, including the northern edge of Yellowstone, Varley said, but in many cases the influence of wolves can be seen with how elk use the landscape.

Instead of lingering in certain spots as they once did, elk now move around more, including some places where they are more vulnerable to predation, such as deep snow, and other places where it's less likely they'll be killed, like hilltops.

"They may still be there, they're just using the habitat differently," Varley said.

Other research presented at the conference included efforts to create a genetic map of the Yellowstone wolf population, the debate over how the presence of wolves affects willow tree populations, and the challenges of reintroducing Mexican wolves in the Southwest.