Hibernation
Hibernation is a very useful word, it is when an animal enters an inactive sleep like state. Small marsupials, rodents, fish, frogs and snakes are all hibernating species. Most animals that hibernate weigh under 20 kilograms. These animals don't need a lot of food to survive. When animals hibernate their body temperature drops a few degrees below the outside temperature, their heart rate and breathing slows a considerate amount as well. Some animals heart beats only five times per minute. Some can go a whole hour with out breathing. Hibernation usually happens during the cold winter months. A good example of a hibernating animal is an echidna. to learn about the echidna click here.