Many animals live in burrows, including moles, groundhogs, rabbits, bears and gophers. Besides mammals, burrowing also occurs among some invertebrates, amphibians, reptiles, fish and some species of birds.
A burrow is either a hole or tunnel that provides shelter and protection from extremes of climate. Some burrows are lived in all year round, and some are used to provide shelter during hibernation and protection while giving birth and raising offspring. Some animals also use burrows to store food. Bears are the largest burrowing animals. They may use caves or dig a burrow out of the dirt or snow.
Some burrowing invertebrates include insects, clams, spiders and worms. Some frogs are burrowers, as well as certain snakes. Birds like the puffin, kingfisher and sand martin dig burrows, while the burrowing owl prefers to use an abandoned nest belonging to a tortoise, ground squirrel or prairie dog.
The extensive burrows that gophers dig are known as gopher towns. A gopher town can consist of thousands of animals and cause great damage to the area. Groundhog burrows are known to even damage building foundations. Meerkats prefer to use burrows dug by other animals. The burrows may have up to 90 entrances and be over 6 feet deep. Snakes have been known to share their burrows.