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　　For some scientists, every day is Groundhog Day．But these researchers aren’t looking for a shadow．They’re trying to figure out how groundhogs each year put themselves into a state of nearly being dead．Body temperature quickly goes down, metabolism(新陈代谢)nearly shuts down, and heart rate slows to something nearly dead．Something changes these normally warm-blooded animals into cool balls．

　　But what? The answers could have deep implications(暗示)for umans．Explaining the mystery of hibernation(冬眠)is necessary for the attractive deep-space travel．If future generations are to stand an interplanetary journey(星际旅行), researchers must learn how to use animal-like hibernation．More immediately ,scientists believe the secrets of hibernation could drive great advances　in stroke(中风)treatment, injury survival and even weight control．

　　“Why is it that this animal can eat like persons who are fat for several months and then shut off for a number of months?” asked Gregory Florant．He studies groundhogs, trying to understand how their energy regulation can change so greatly．

　　Contrary to popular ideas, hibernating animals don’t sleep for the winter and wake up in the spring．Hibernation is not sleep．An animal will periodically wake and then go back down into a state known as torpor(蛰伏)．The particular mark of hibernation is a great rise and fall in metabolism-wild swings(突然转变)in body temperature and blood flow that a person could not stand．

　　Since so many different mammals can hibernate, scientists believe the ability for human to survive similar changes of metabolism is probably buried in the genetic code, which remains a mystery．“We are mammals, therefore we share genes with other mammals that can do this,” Dr．Florant said．“We haven’t discovered what genes are directly involved．”

　　But researchers have recently gained some important breakthroughs about the process．

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