The North American Beaver

The North American beaver is the largest rodent in North America. Beavers range from southern Alaska to northern Mexico.

Adults usually weigh 11 to 32 kilograms. The species conforms to Bergmann's rule—northern animals appear larger.

Beavers possess continuously growing incisors. They use front feet for digging and maneuvering stems. They never have to schedule a dentist visit.

North American beaver ancestors grew as heavy as a large adult human.

Scent glands near the genitals secrete castoreum. Beavers use this oily substance to waterproof their fur.

Where woody material is limited, beavers build dams largely of rocks. Running water dictates construction.

The largest beaver dam is 2,790 feet long. It was discovered via satellite imagery in 2007 in Wood Buffalo National Park.

Reintroduction restored the species to most of its natural range. Populations rebound across boreal and temperate ecoregions.