American Beaver

American Beaver

American Beaver

Castor canadensis

Status: Not Listed

Classification: Mammal


The American beaver's most noticeable characteristic is the long, flat, black tail. A beaver’s tail not only helps it swim faster, but can also be used to make a loud alarm call when slapped against water. In addition, the large tail helps the beaver balance when carrying a heavy log or tree trunk.

The American beaver is the largest rodent in the United States, growing from two to three feet (0.6 to 0.9 meters) long, not including the tail. They have dark-brown waterproof fur and webbed feet. Beaver teeth grow continuously throughout their lives, and beavers must gnaw on trees to keep their teeth from getting too long. Thick layers of enamel on their teeth give them an orange color.


Beavers live in ponds, lakes, rivers, and streams throughout the continental United States, except in the desert areas of the Southwest. Beavers are well known for their ability to build dams. They are one of the few animals that can actively change an ecosystem by blocking rivers and streams with trees and mud, creating new lakes, ponds, and floodplains.

Beavers also build homes called lodges out of branches and mud, which can often only be accessed from underwater entrances in the ponds.


Beavers are semi-aquatic herbivores. They travel from water to land to collect and eat tree bark, leaves, roots, and wetland plants.

Life History

Beavers are monogamous. They mate at around three years of age. Females gestate the young for roughly three months before giving birth. A female will typically have one litter of kits a year, with litter size ranging from one to four kits. These kits, along with those born the previous year, stay with their parents inside the lodge.


American beaver populations are stable.

Fun Fact

Beavers can stay underwater for 15 minutes without coming to the surface. They have transparent eyelids that act as goggles so they can see as they swim.

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