The dam is built like a layer cake except that it is held together by mud, not icing, which is smeared on with their paws and noses. Beavers can build a 35-foot long dam in just one week. The beaver family is called a colony. A female has to wait three and a half months for her kits to be born. While she waits she builds warm, comfortable beds by splitting soft wood into thin chips.
Beavers usually have a litter of four kits who live with their parents for two years.
The life span of beavers can be up to 19 years. An adult may grow to be four feet long including the tail and weigh more than 60 pounds. Beavers have a wide, flat tail that looks like a paddle and is covered by scaly skin. It serves as a prop when the beaver sits upright and as a rudder when it swims. The beaver also uses its tail to alert other beavers by smacking it on the water.