The discovery of a possible hibernation hormone in the brain may unlock the mystery behind the dormant state, researchers reported in the April 7, 2006 issue of Cell. Hibernation allows animals from bears to rodents to survive unscathed--in a state of suspended animation--under the harshest of winter conditions. If the findings in chipmunks are confirmed, the hormone would represent the first essential brain signal governing the seasonal adaptation, according to the researchers.