Grizzly Bears are not ’true’ hibernators. Instead they have a period of extended sleep called ’dormancy’. They do not eat or drink until they emerge again in the Spring. Extra fat is accumulated in the autumn to maintain them over the 4-6 month hibernation period. By Spring they may have lost 30% of their body weight. Hibernating bears will awaken and move around during the winter months, unlike other hibernating animals that cannot easily be roused. http://www.grousemtn.com/adv_wilref_gribea.cfm グラウス山にスキーに行ったときレストハウスでクマの小屋の中がテレビカメラでモニターできました。 確かに動きまわって寝てなかった。