Bears sleep through annual checkups

CAMP RIPLEY, Minn. (AP) -- Brian Dirks crept quietly through the snow, halting every couple of steps to lean forward as he peered ahead.

There, in a hollow beneath a downed maple tree, was a black bear den, with an adult female slowly lifting her snout skyward. "She definitely knows we're here," he whispered.

Dirks is one of two wildlife biologists from the Minnesota Department of Natural Resources who are stationed year-round at Camp Ripley, about two hours north of the Twin Cities. The 53,000-acre camp is used for artillery practice, tank maneuvers and other military training, especially during the summer.

Sharing space with soldiers firing live ammo and conducting night training exercises are the camp's permanent residents: nearly 30 black bears, two packs of wolves, hundreds of deer, wild turkeys, rare turtles, bald eagles and the state's largest population of red-shouldered hawks.

The rich wildlife diversity has made the camp an ideal spot for research, and early March is the time when bears in a dozen dens receive their annual physicals.

It's a tricky proposition: Bears in hibernation can be light sleepers.

"They have periods during the day when they're more awake, and periods when they're more asleep," said Julie DeJong, Dirks' DNR colleague. "They can flee; they're awake enough to do that."

So researchers must sneak up on the bears and tranquilize them before they wake up enough to run away. For DNR bear project leader Dave Garshelis, the method of choice is a syringe at the end of a long stick. After sticking the mother and waiting for the drug to take effect, the female's yearling cub poked her head out of the den, yawned and quickly retreated. She also received the sedative.

Camp Ripley environmental supervisor Marty Skogland said the military asked DNR researchers for help in 1989. At the time he was receiving hundreds of complaints each summer from frightened soldiers who saw bears crawling into their tents and vehicles.

"The soldiers were storing garbage on site and even feeding bears sometimes, so whenever the bears heard a bunch of vehicles coming, it was like ringing a dinner bell," Skogland said.

The camp solved the problem by prohibiting food storage in tents and by hauling garbage daily from campsites. "A lot of the problem was people management, which wildlife management often is," Skogland said.

Garshelis said the Camp Ripley bears are part of a statewide study comparing bears in other parts of their range, including the Grand Rapids area and Voyageurs National Park. Researchers collect data on overall health, size, weight, reproduction and mortality rates, and other details.

Using radio collars, scientists can also track where they roam during the summer. That's especially interesting for Camp Ripley's population, said Garshelis, because the bears live at the southern edge of their range and not far from farmland. Minnesota has about 25,000 black bears, he said, and they typically hibernate from late November until April.

As Garshelis and others hauled the sedated bears from the den, Paul Iaizzo, University of Minnesota professor of surgery and physiology, was unpacking equipment to conduct heart tests.

"The bear in hibernation is basically in a state of starvation for four or five months, but its heart function doesn't change much at all, and it loses almost no muscle strength," Iaizzo said.

If humans were immobilized for a similar length of time, he said, they would lose 80 percent to 90 percent of their muscle strength. Iaizzo is also intrigued that bears enter hibernation with various wounds, which heal completely during hibernation.

"Humans without nutrition won't heal at all," he said.

Learning about bears may lead to new drugs or other discoveries helpful in treating heart or muscle disorders, Iaizzo said, or in countering the effects of prolonged hospital bed confinement -- or even long-distance space travel.

While researchers fitted a bright orange neoprene radio collar on the 55-pound yearling, sixth-graders from Mary of Lourdes School in Little Falls surrounded the bears. They questioned the researchers, petted the fur, rubbed the worn paws, posed for photos and ventured to the nearby den.

Skogland said Camp Ripley tries to open the camp as much as possible to environmental education. It has also worked with the DNR and the Nature Conservancy to receive advice and technical help to manage the land, protect native species and burn some of its prairie grasses each year. The camp has also begun an initiative to pay willing landowners just outside the camp to restrict development.

Dust, smoke and especially noise from large-scale training and artillery fire migrate several miles away from the camp, and officials are concerned about future residential development.

"We need to remain a viable training site into the future," Skogland said.