<b>what is hibernation</b><br> Hibernation is a way that some animals deal with the harshness of winter. They curl up in a safe place and stay there until winter ends. Hibernating animals seem almost dead. They barely breathe, and their body temperature is near the freezing mark. In warmer weather they return to their regular activities. <b>why hibernation</b><br> A hibernator’s body responds to weather conditions. If the weather becomes too cold, the animal needs to move around to raise its body temperatures. An animal that does not do this may die. Warmer temperatures tell an animal to come out of hibernation. There are many winter survival strategies in the animal world, and one of the most fascinating is hibernation. Some animals enter a state of "suspended animation." Their breathing and heart rates slow and they allow their body temperature to drop, in some cases even below freezing. They stop eating and in many cases stop excreting. All of these things happen so the animal can use less energy. <b>who need to hibernate</b><br> Animals that hibernate are called hibernators. They include bats, hedgehogs, ground squirrels, groundhogs, and marmots. <b>how to hibernate</b><br> Hibernators like dark, quiet winter homes. Some go underground or into caves. They may line their hibernation place with grass, hair, and other materials.<br><br>Hibernators prepare for winter with extra eating. They store fat to keep them alive during the months when they do not eat. Some hibernators collect and store food before hibernating. At times during hibernation, these animals arise to eat and then return to hibernating. Bears are an example of animals that change their activities in the winter but are not true hibernators. They spend most of the winter asleep, but their body temperature barely drops. A bear will move around if woken up. Also, females give birth and nurse during this time.熊不冬眠，只是睡觉 <b>where to hibernate</b><br> Many reptiles and amphibians of mild climates become inactive in winter. Frogs and toads rest in holes or in mud at pond bottoms. Snakes may crowd together in caves. Many insects and spiders are frozen solid during the winter. they enter into something called brumation. This involves inactivity, torpor, and a slowed metabolism. They’ll wile the winter away like this, burrowed in places like stream bottoms, stump holes, or animal burrows. This can last for three to five months. This is when a bat’s body’s metabolic, heart, and respiratory rates plummet to allow them to survive long periods without food. Their body temperature can also dip to near freezing. During this state, bats will seek out shelter in spots like caves, mine shafts, and attics. During the cold months, chipmunks hole up in their burrows with stored food. Most of this time is spent in a deep sleep, in which their heart rate drops from around 350 beats per minute down to about 4. Their body temperature can also lower to the temperature inside. Every few days, though, they wake up, their body temperature stabilizes, and they eat and relieve the call of nature. Frogs are cold-blooded, meaning they can’t produce body heat with their metabolism, so it’s off to hibernation they go in the winter. For aquatic frogs, this period is passed underwater, where they breathe in bits of oxygen through their skin. For terrestrial frogs, the choice typically falls on soil beneath the frost line or in cracks or crevices in logs and rocks. SNAKES They actually hibernate in groups, to keep their body temperatures up. These groups will choose locations like natural cavities or burrows, under rock piles, or in stumps. While they hibernate, they will not eat, but they do absorb moisture through their skin to stay hydrated. HEDGEHOGS They’ll either create their own resting place with dead leaves, twigs, and other materials, or they’ll settle into stacks of logs or compost heaps.