Issue link: http://digital.canadawide.com/i/170490
Walking Hibernation Two cubs tumble out of the den after their mother. Marsha sniffs, wary of male bears, wolves, and other animals that might eat her cubs. They hang around the den for a couple of weeks before Marsha heads down the mountain, the fuzzy siblings tagging along, rolling on the damp ground, nipping at each other, pausing to suckle when Marsha flops down on a warm squirrel midden to rest. She's lost almost 30 percent of her body weight over winter. She rises, saunters through the trees, cubs trailing at her sides. Marsha's destination is the riverbank to feed on skunk cabbage, an early spring treat. Wake up after a long sleep, it's chilly, and the only food in the house is . . . asparagus. That's about what bears face as they climb out of their dens as early as mid-March for coastal bears and as late as the third week of May for northern Interior bears. Males usually emerge first, followed by lone females, and finally the mothers, who wait to the last possible moment to give their cubs time to mature. With his gadgetry Tøien proved what field biologists like Hamilton noticed behaviourally. Bears may have left the den, but physiologically, they're still inside for two to three weeks. "They walk around with a resting metabolism about half that of a normal bear in summer," Tøien says. His captive bears would lie on top or just inside the den entrance, with their heads poking out. In the wild, bears spend hours snoozing in day beds—depressions they've dug—or on dry spots under old growth tree branches that sweep the ground, tree stumps, or squirrel middens. Meanwhile, the forced veganism continues. Bears grind nutrition out of horsetails, nip off the tops of Indian Hellebore, and target the petioles (the stalks that attach leaves to a plant stem) of skunk cabbage. Hamilton's research has shown that skunk cabbage has more protein when bears need it most, spring and fall. Though serious omnivores with the molars to prove it, bears rarely pass up meat. In early spring, a herring spawn lures coastal bears to the seashore. If they miss the spawn they'll find the next best thing on the beach: biologist Caroline Fox with the Raincoast Conservation Foundation has documented a black bear slurping sand fleas that fed on herring roe. After six or seven months, emerging mountain grizzlies face lighter fare: overwintering bearberries or wildflower bulbs, like glacier lilies. They'll eat anything they can find, confirms Lana Ciarniello, a bear biologist who studied grizzly bears of the Interior Plateau and the Interior mountains. "It's quite slim pickings in spring," she says. A lucky mountain bear might make a rare find—a dead caribou caught in an avalanche during the winter. The plateau offers more emerging vegetation for bears in general. Favoured greens include the dandelions and clover that blanket cutblocks (deforested areas). B r itish C o lumbia M agazine • fal l 2 0 1 3 25