Bears are waking up.

Minnesota's black bears are emerging from their winter dens this time of year, as weather warms and plants and insects return as sources of food.

The bears shake off their winter state of torpor, when their heart rates slowed and they didn't eat, drink or defecate for about six months to conserve energy under cold temperatures and scarce food. They can lose up to half their body fat during the winter slumber.

After emerging in the spring, bears eat lightly on the few plants and leftover acorns and fruits they can find as their digestive system fires up again. Mama bears have a right to be ravenous once they're fully functioning. They wake to give birth between January and February and continue to rest while nursing an average of two or three cubs. The babies come into the world at less than half a pound, but they can reach five or six pounds by late March.

The Minnesota Department of Natural Resources estimates 13,000 to 18,000 black bears live in the state. If you split a state map diagonally from the northwest corner to the southeastern corner, bears live mostly in the north and east section, in coniferous and deciduous forests. They have, however, been expanding south and west and have wandered near St. Cloud, the Twin Cities and Rochester metropolitan areas in the past. Sightings in these areas can be reported to the DNR.

To find food in early spring, bears rely on a sense of smell that's seven times better than a bloodhound. According to the Bear Wise, they can sniff out bird feeders, greasy barbecue grills, food trash and pet food from a mile away.

David Joles, The Minnesota Star Tribune
A black bear and her cub roam a corn field on the edge of a woods near Grantsburg, Wis.

Now is a smart time to bring in bird feeders at night or risk finding them broken or simply gone. Look around and remove any other attractants, as shy bears tend to do food raids after dark. You can find more tips for safely recreating and living in bear territory on the DNR website.

Lisa Meyers McClintick has freelanced for the Minnesota Star Tribune since 2001 and volunteers as a Minnesota Master Naturalist.