Have you ever wondered why certain animals surface during only certain parts of the year? It may be because they are hibernating. When animals hibernate, it means that they are going into a deep and prolonged sleep. Animals mostly do this in the winter times when the temperature outside is very cold and food is hard to find. Different animals follow different patterns of hibernation. Animals can put themselves into a deep sleep for as long as several months. This brief video provides an overview of hibernation. [1:19]