Hibernation is more than sleep. It is a very deep sleep.The animal's temperature drops to just over zero centigrade, and its heart beats very slowly.People who find hibernating animals asleep often think that they are dead: the body feels very cold, and the creature may breathe only once every five minutes.A hibernating animal cannot feel any pain.You can touch it, or even pull its tail, without causing it to move or wake up.In its hibernating state it can even live in a poisonous atmosphere for a long time without any ill effect.

　　冬眠不仅仅是睡眠，而是一种沉睡。动物的体温降到刚好在零摄氏度以上，心脏跳动非常缓慢。人们看到处于冬眠状态的动物，常常以为它们是死的：身体摸上去冰凉，可能每5分钟才呼吸一次。冬眠的动物感觉不到任何疼痛。你可以摸它，拉它的尾巴，也不能使它动一动或醒过来。当它处于冬眠状态时，甚至可以长时间地生活在有毒空气中而无任何不良后果。