Minnesota's bear population is likely a little more than 20,000 animals, down from the last complete population estimate of 25,000 bears in 2002, according to Department of Natural Resources wildlife biologists.
In 2008, DNR bear researchers launched a population study by putting out baits that contained tetracycline. The chemical subsequently can be detected in the bones and teeth of animals that ingest the baits.
In the 2008 and 2009 bear hunting seasons, researchers asked successful hunters to return a rib and two teeth from the bears they killed. By comparing the number of bears marked with tetracycline by the baits to the ratio of marked and unmarked bears in the harvest, biologists can determine the size of the bear population.
First-year survey results typically skew the population estimate lower than it really is, said Dave Garshelis, DNR bear project leader in Grand Rapids. But now, after two years of results, the study indicates about 20,000 bears roam the state.
He estimates that after this fall's hunt and subsequent bone and tooth analysis, the population estimate will increase further.
"We wanted to try to bring the population down a little bit, just to show that we still could," Garshelis said. "There was a lot of uncertainty about the direction the population was headed. .... Some people thought it was possible we couldn't control the population by increasing the number of (hunting) permits. We said, 'Let's see if we can do that.' "
The DNR increased the number of bear-hunting permits through the 1990s, leveling off at about 20,000 permits from 1999 to 2003.
That coincided with a period when permit applications declined. Hunters were frustrated with crowding in the field, Garshelis said.
The DNR decreased permit numbers from 2004 to the present, but harvest has remained fairly constant at about 3,000 per year.
Counting bears isn't easy, said Mike Schrage, wildlife biologist at the Fond du Lac Band of Lake Superior Chippewa.
"I think the DNR is using probably the best available science to count an animal that is really difficult to count," Schrage said. "Whether there are too many or too few probably depends on whether you saw a bear while hunting last fall or whether your garbage can got knocked over last night."
Dennis Udovich, president of the Minnesota Bear Guides Association, said the bear population and bear permit numbers are at good levels and most hunters are happy. By reducing permit numbers, the DNR has solved the crowding situation that occurred earlier in the decade, Udovich said.
"Dave Garshelis and Karen (Noyce, a DNR bear research biologist), they do a great job. They're on top of that game," Udovich said.
The DNR doesn't have an official population goal for bears, Garshelis said.
"I think it's a bit of a moving target," he said. "We try to balance recreational opportunities (hunting and wildlife viewing) against human-bear conflicts."
Northern Minnesotans have learned how to live with bears and are more tolerant of them than they were 20 to 30 years ago, Garshelis said. Complaints have been low for several years. Part of the reason for that is that DNR wildlife officials no longer move "nuisance" bears. The DNR has worked to educate people about how to avoid bear problems, and people have responded.
"Thus, the 'social carrying capacity' for bears seems to have increased, allowing us to manage for a higher population," Garshelis said. "A population of about 25,000 is a rough, short-term, but not official, goal."