Posted by Ranger Sally (165.83.4.127) on April 12, 2002 at 08:42:32:
In Reply to: Prey species posted by MO on April 11, 2002 at 15:23:31:
: What prey species (other than rodents that they dig out) do bears have the ability to hunt and kill? What strategies do they use to hunt? And how successful are they?
Thanks for your question, MO. Several studies have documented grizzly bear predation on elk. Most of this predation seems to occur on winter-weakened animals, newborn calves or fall predation on adult male elk during the breeding season. Grizzlies used 3 techniques to hunt elk calves. In May and early June when newborn elk calves are very immobile, bears were observed locating newborn calves, probably by scent, in calving areas. Bears then moved through the area in a zigzag pattern, occasionally rising onto their hind legs. (Nine out of 70 hunts observed used this method and produced six successes). A second technique was for the bear to approach cow/calf groups at a loping pace while in the open, making a series of charges in order to separate confused calves from the group and then concentrate on the calves. (of the 70 hunts observed, 59 used this technique, resulting in 18 successes). The third style of hunting involved the use of cover. Bears used tree cover to approach elk grazing within 50 m of the forest edge, then rushed from the trees and began to chase (2 of the 70 observed hunts used this technique and both hunts were successful).
Of ten hunts observed on adult elk, 8 were unsuccessful, 2 had an unknown outcome). Grizzlies were observed hunting adult elk from May through July and no attempts of predation on adult elk were observed in August or September.
There has also been some documentation of bears killing moose, deer and bison calves but most of their predation seems to be on elk calves. They've also been observed chasing (unsuccessfully) ducks, Canada geese, and sandhill cranes. In addition, they have successfully caught cutthroat trout and longnose suckers.