North American BeaverCastor canadensisDónde y cuándo verlos

The North American beaver is North America's largest rodent and a highly specialized semiaquatic mammal. Native to much of the continent, it occurs throughout the Columbia and Mississippi river basins wherever suitable freshwater habitat and woody vegetation are available. Its tree cutting, dam building, and canal digging can transform waterways and create wetlands used by many other species. Extensive trapping once greatly reduced its populations, but protection, reintroductions, and habitat recovery have helped it return to much of its former range.

Size

Adults typically measure 90–120 cm (35–47 in) in total length, including the tail.

Weight

Adults generally weigh 11–32 kg (24–71 lb).

Lifespan

Typically 10–12 years in the wild, although some live longer.

Status

Least Concern (IUCN)

Beavers are mainly active at dusk and during the night, though daytime activity also occurs. They usually live in family groups consisting of a breeding pair and offspring from more than one year. Family members cooperate in maintaining shelters, storing food, and defending their territory. They mark territory with scent deposited on small mounds near the water. On smaller waterways, they may build dams that maintain water deep enough for safe travel and access to shelter. Along large rivers, they often occupy bank burrows or bank-associated lodges without damming the main channel. A sharp slap of the broad tail against the water can signal alarm.

• Their orange incisor enamel contains iron, which helps strengthen the teeth.
• Their incisors grow continuously and are worn down through gnawing.
• Their lips can close behind the incisors, allowing them to gnaw underwater.
• Their broad tails help with steering, balance, and heat regulation.

Wildlife opportunities depend on the river reach, water levels and species. River-specific viewing months have not been confirmed; general species seasons are not a local sighting forecast.

Beavers inhabit rivers, streams, ponds, lakes, and freshwater wetlands with accessible vegetation. Along the Columbia and Mississippi, suitable places include sheltered side channels, sloughs, tributaries, and floodplain wetlands. They need water deep enough to reach underwater shelter entrances and nearby plants for food and construction materials. Willows, cottonwoods, and other riparian trees provide valuable resources, while steep or stable banks can offer sites for burrows.

Beavers are herbivores that eat bark, the living tissues beneath bark, twigs, leaves, and aquatic vegetation. Willows, cottonwoods, aspens, and other deciduous plants are important foods, depending on local availability. Their diet shifts seasonally, with more leafy and herbaceous plants eaten during the growing season and greater reliance on woody foods in winter. In colder areas, they store branches underwater near their shelter for winter feeding.

Common name

North American Beaver

Scientific name

Castor canadensis

Animal group

Mammals

Size

Adults typically measure 90–120 cm (35–47 in) in total length, including the tail.

Weight

Adults generally weigh 11–32 kg (24–71 lb).

Lifespan

Typically 10–12 years in the wild, although some live longer.

Status

Least Concern (IUCN)

Identification

Look for a large, stocky brown rodent with a blunt head, small rounded ears, and a broad, flattened, scaly tail. A swimming beaver often shows mainly its head and part of its back, so the distinctive tail may be hidden. Compared with muskrats, beavers are much larger and lack a narrow, vertically flattened tail; nutria have a rounded tail and often conspicuous pale whiskers. Freshly gnawed stumps and branches are useful signs, but do not necessarily mean a beaver is currently nearby.