grizzly bear hibernate every winter. they sleep for a long time . they don not wake up or eat for several months.when the y wake u in the spring. the grizzlies are in danger again. but in alaska . in u.s the grizzly bears are not alone. timothy treadwell is there to protect them. he sleeps in a tent near the bears and bathes in a river with them too . people do not hurt the bears when timothy is with them