After spending the hot summer days playing in the sun and warm fall days collecting food, animals have to prepare themselves for the bitter cold. Unlike humans, they do not build elaborate homes with heaters and chimneys to keep them warm. Yes, they do have a warm fur coat, but it is no match for the freezing temperatures after the mercury drops down. In order to face the winter bravely, many animals adapt themselves. There are many types of adaptations, some start migrating towards warm regions, some build a thick fat layer and fur coat over their body and some just sleep. There are many animals who hibernate in winter. In the following paragraphs, we shall have a look at the hibernating animals list that will help you know which neighborhood wilderness animals sleep their way through winter. List of Hibernating Animals There is a long list of hibernating animals that includes mammals, amphibians, fish, reptiles, insects, birds, etc. Bees, earthworms, snails, mud turtles, butterflies and moths, gila monster, wasps, rodents all undergo hibernation. As you take a picture tour of the hibernating animal lists, we shall cover information related to why do animals hibernate. Why do Animals Hibernate? Cold winters is when the food is scarce and with freezing temperatures, it sure is no picnic for most animals. To top it all, the days are short and nights are very long. Winter seems never-ending for most who don't have enough protection for winter. Animals end up losing more calories than usual, rendering them weak. This is because their bodies use up more energy to keep them warm, and other half of their energy is lost in searching for food and shelter. Also, not all animals are social animals and will not pack together to keep themselves warm. Starvation or freezing to death, the choices are tough. In order to get by these difficult situations, animals have adapted themselves. This adaptation as mentioned earlier, is called hibernation. Hibernation is a type of deep sleep an animal enters. This helps to keep its energy needs to the minimum and helps them regulate their body temperatures better. As they are sleeping, they do not need to search for food, and the fat and calorie build up helps them get through their hibernation period. There are different habits followed by animals that hibernate. Like a squirrel sleeps for about 4 to 5 days at a stretch and will wake up, again eat something of the food it has collected all summer. Go for a toilet break and them go back to sleep for 4 to 5 days. When it comes to bears, they just sleep all winter, without a break and wake up fresh and very hungry after winter is long gone. What Happens During Hibernation? Physiological inactivity is hibernation. Animals know when winter is about to start with the help of external stimuli. When they do know it is time to hibernate, they produce a hormone called 'hibernation-specific protein'. This hormone starts lowering their metabolic activity and induces sleep state. Soon, the heart rate drops, breathing becomes slow and the blood supply gets restricted. The non-essential organs start entering a state of stasis. This leads to drop in core temperature and the internal temperature is more or less equal to external temperature. Thus, the energy requirement is reduced and the animal can survive winter. Which Animals Undergo Hibernation When you have a look at the list, you will find a variety of species who follow this survival strategy. Mammals such as bats, bears, ground squirrels, undergo hibernation. Reptiles like tortoises and snakes, too undergo sleep state. Birds like Poor-Wills, swifts, and nighthawks, as well as amphibians like toads and frogs too hibernate. These animals store food as body fat during the months of summer and fall. When they hibernate they use up their body fat for the little energy that they need to live during hibernation. Some animals like squirrels store their food in burrows and caves. This food works as a light snack when they do wake up from their sleep for a break. In case of cold-blooded animals, their body temperatures drop with the drop in environmental temperatures. This means their body temperatures will match the environmental temperatures. When the temperatures outside begin to change, and the air becomes warmer, these animals will wake up from their deep sleep. This was all about the hibernating animals list. Hibernation is a path of evolution that was taken by most animals to survive harsh winters. The next time you pass an animal in deep sleep during winter, do not wake him up. Wish him good night and allow him to complete his body cycle.