Beavers are the largest type of rodents. They have short legs, and a humped back. They also have a wide, flat tail that is twelve to eighteen inches long, and six inches wide. Their flat tail is covered with black, scaly skin. Beavers themselves are roughly 1 m long, and weigh between 40 and 95 pounds. Adult beavers are about the same size as an eight-year-old human child. Beavers can live up to 20 years, and they continue to grow as long as they live.

Beavers also have small eyes and ears, and strong jaws. Beavers have sharp front teeth for gnawing. These are called incisors. They're incisors never stop growing. They also have 16 back teeth for chewing called molars. There is a large gap between a beaver's incisors and molars.

Beavers have two yellowish, brown fur coats to keep them warm. The outer coat, consisting of long, guard hairs, protects the soft, thick under-fur underneath. Under-fur traps air next to the beaver's skin and helps the beaver stay warm underwater. Beavers comb their fur with two split nails on each hind foot.

Beavers live near wooded areas in lakes, rivers, or streams close to forest. More beavers live in North America than anywhere else in world.

A beaver's home is called a lodge. Beavers build their lodge in a pond, lake or a stream. Their lodge extends above and below water. Their lodge mainly consists of mud and sticks. A beaver's family inhabits its lodge.

A beaver builds its lodge by first getting wood by bringing down. But before they start, a beaver makes a hole in a stream bank, and uses that as a temporary home while they build. To bring down a tree, the beaver first makes deep cuts all around the tree with it's strong teeth. Secondly, it makes more cuts about three inches below the first. The beaver gnaws away at the wood in between the two cuts until it has cut through the trunk. When the tree is down, the beaver gnaws off all of the branches. If the tree is near a stream, the beaver drags or rolls the log into the water. When the trees are farther away, beavers dig a water channel called a canal. Afterwards, the beaver floats the trees down the stream to where they are building their lodge.

Next, beavers build a dam. A dam is structure built to control the water flow of a stream. They build the dam high enough and wide enough to keep water from flowing over or around them. The whole beaver family helps to keep the dam and lodge in good repair. If a river or lake is too deep, beavers cannot build a dam there. Soon a pond forms behind the dam. The pond may be three to six feet deep. Now the beaver family can build a lodge with an underwater entrance in the middle of the pond. The lodge's top rises above the water level, and the entrance is an underwater tunnel, which keeps enemies out of their lodge. The roof of the lodge is covered with branches so air can get into the lodge. Before winter comes, beavers add more layers to the roof and smear it with mud. This keeps the lodge warm and dry, even during the heaviest snows and the coldest weather.

Inside the lodge, beavers build ledges above the water level. The ledges are covered with a thick layer of wood chips and grass. Beavers sleep on these dry ledges. Afterwards they burrow or dig into the riverbank and build a roomy den. The entrance is underwater, and the tunnel leads upward to the den in the riverbank, high above the water level.

Beavers are herbivores, meaning they only eat plants. Beavers eat tree bark, twigs, leaves, grass, roots, twigs, and water lilies. They prefer willow, birch, aspen, and poplar trees. In the spring and summertime, beavers eat marsh grasses, roots of water plants, clover, and berries. Beavers use their long sharp claws to dig up some of their food. They keep their food close to the lodge. Beavers save food for the winter. Beavers are always chewing, and can cut down trees at night to chew on the branches.

Beavers do not hibernate, or sleep through the winter, so they must gather a food supply. They store twigs and branches underwater near the lodge entrance. Cold water keeps the leaves and branches fresh.

Beavers usually have 1 litter every year, and two to four babies in each litter. Beavers' babies are called kits. Beaver Kits are covered in soft fur when they are born. Kits weigh about the same as a baseball when they are born. Kits drink their mother's milk. When they are only few days old, kits able to eat plants. Kits usually stay with their parents until they are two years old. By autumn, the youngest kits are ready to work with their parents and older brothers and sisters.

Beavers played important part in North America history. In 1700s and 1800s, hats made of beaver fur became popular, and high prices were paid for beaver fur. Trappers hunted beaver fur throughout western United States and much of Canada. By the late 1800s, beavers were almost extinct.

In many states in the U.S., law now protects beavers. Permits are needed to trap beavers today, and beavers can only be trapped at certain times of year. Beavers' dams and lodges cannot be removed without a permit either.