During that time, the metabolism slows down, the bears are very lazy. Heart and breath rate slow down, too. You can compare it with when people are in a deep-sleep phase. In case of danger, they can wake up anytime. Some bears completely disappear for about three months and don’t drink or eat anything, others longer with some food breaks. Others sometimes leave their dens when it’s good weather and look for food. But they don’t eat a lot, at the most about three kilos. Then they go back to sleep. Read more about bear hibernation.