American Beaver

• Only the colony's dominant female breeds each year.
• It eats the bark, leaves and twigs of trees such as willow and poplar.
• It lives in rivers, lakes and streams across much of North America.
• ecologíaIt can transform an ecosystem outright by building dams that create whole wetlands, which is why it is considered a keystone engineer.
• anatomíaIt can close its lips behind its front incisors, so it can gnaw wood while fully submerged.

Skeleton type

Vertebrate - internal bony skeleton (mammal)

Habitat and environment

Rivers, lakes and streams across much of North America

Birth weight

230-630 g at birth, fully furred and with eyes open

Size at birth

230-630 g at birth

Sexual maturity

1.5-2 years

Gestation / incubation

~4 months

Litter / clutch size

2 to 4 young per litter (average 2.3-4.1)

Life expectancy in captivity

Documented record of up to 23.4 years

Sources consulted: US Forest Service FEIS · AnAge (genomics.senescence.info) · Michigan State University Brain Museum