They were once widespread in N and central Eurasia except E Siberia, and in North America from the arctic tree line to the S United States. Because of their great importance in maintaining the natural environment, they have been reintroduced in many areas of North America and Russia and are now increasing in numbers. Beavers are responsible for creating many of the woodland ponds that support lush vegetation and eventually become meadows.
Beavers can swim underwater for 15 minutes. They can do that because they have very big lungs. Their tails are used as a rudder. If they turn their tail to the right the beaver will go left. Beavers have noses and ears that close when the beaver is in the water.
Humans are the main enemies for beavers everywhere. In the north, wolves are the main predator for the beaver. When a beaver is on land looking for food it can be attacked by animals like: coyotes, lynx, bobcats, mountain lions, wolverines, bears, and sometimes stray dogs. Beavers are hard for an animal to kill because they can dodge into one of their plunge holes. Sometimes a beaver will bite its enemy with its sharp teeth and drag their enemy to the water to drown.
Sometimes a beaver will communicate with another beaver by making a scent post. A scent post is a hill made out of mud and grass. They communicate with them by putting musk-smelling oil from their castor glands on the hill. The smell attracts beavers and other animals. Some scent posts found have been 8 to 10 inches high and 10 to 12 inches around. The scent post does more than help them communicate, it finds them a mate.
Beavers live 16 years. They are about 4 feet long including a 1 foot tail, and they weigh up to 60 lbs. They mate from Jan.- Feb. and they have 1 to 8 babies in April-May. The babies weigh 8 to 24 oz., their length is about 13 inches with tails that are about 9 centimeters long. They learn to swim when they're only a month old. Their eyes open at birth. When the second litter is born the first litter moves out. Beavers mature in about 2 to 3 years. The prehistoric beavers were 7 feet, 6 inches long and lived in North America.