Beaver

Beavers at a glance

Need to know

• Beavers are the second-largest rodents in the world, after capybaras.
• They are renowned for their dam-building skills, transforming landscapes and creating wetlands.
• Beavers have transparent eyelids, allowing them to see underwater.
• Their incisors are orange due to iron in the enamel, making them extra strong.
• Beavers were nearly driven to extinction by the fur trade, but have since made a significant comeback.
• Their lodges are so well-built that they can even provide shelter from predators and harsh winter weather.

About the Beavers

Beavers are large, primarily nocturnal, semi-aquatic rodents known for their incredible engineering skills in building dams, lodges, and canals. These animals are ecosystem engineers, significantly shaping their environment by slowing water flow, creating new wetlands, and benefiting a great number of species. Beavers once faced severe population declines from trapping for their luxurious pelts, but major conservation efforts led to one of the greatest wildlife recoveries in modern history. Today, both the North American beaver and Eurasian beaver have stable, even expanding, populations thanks to legal protection, reintroduction programs, and habitat recovery.

Physical characteristics

Size: 90–120 cm (average), up to 135 cm including tail. Weight: 16–30 kg average, up to 40 kg for largest males. Lifespan: 10–12 years on average; up to 24 years reported in captivity.

• Large flat, scaly tail used for swimming and communication
• Webbed hind feet for powerful swimming
• Orange, iron-fortified incisors for gnawing wood
• Dense, waterproof brown fur
• Robust, rounded body adapted for aquatic life

Notable species

• North American Beaver (Castor canadensis) — Least Concern. Freshwater rivers, streams, ponds, and lakes with access to deciduous trees Regions: Canada, United States, northern Mexico, Alaska, Great Lakes region.
• Eurasian Beaver (Castor fiber) — Least Concern. Riverbanks, floodplains, forested wetlands, and streams across Eurasia Regions: Scandinavia, Eastern Europe, Western Europe, Russia, Central Asia.

Habitat and range

Original range: Northern and temperate forests across North America and Eurasia

Current distribution: Widespread throughout most of North America and much of Europe and Asia, with expanding or reintroduced populations in western and central Europe

Preferred environments: Freshwater rivers, Streams, Lakes, Wooded wetlands, Riparian forests

Regions: Canada, United States, northern Mexico, Alaska, Great Lakes region, Scandinavia, Eastern Europe, Western Europe, Russia, Central Asia

Where to see Beavers

• Algonquin Provincial Park, Canada — Late Spring to Early Fall (May–September). Look for evening and early morning activity near ponds and beaver lodges.
• Białowieża Forest, Poland & Belarus — Spring and Autumn. Visit rivers and quiet backwaters at dawn or dusk to spot Eurasian beavers.

Behavior and diet

Diet: Primarily herbivorous: bark, twigs and leaves of deciduous trees (aspen, willow, birch, poplar); also aquatic plants and grasses.

Social structure: Family-based colonies; monogamous pairs with kits (young) from multiple years may share the same lodge.

Communication: Vocalizations, scent marking with castoreum, tail-slapping, posture and body language.

• Building complex dams and lodges from sticks and mud
• Store branches underwater for winter food supply
• Tail-slapping as a danger signal
• Digging canals to move food and materials efficiently

Interactions with other animals

• Wolf (predator): Wolves may hunt beavers in areas where their populations overlap, especially when other prey is scarce.
• Amphibians/fish (symbiotic): Beaver ponds create wetland habitats beneficial for amphibians and fish species.
• Muskrat (competitive): Muskrats may use beaver lodges and compete for food and space.

Conservation

IUCN Red List status: Least Concern (both species, global populations)

Threats

• Habitat loss from wetland drainage and agriculture
• Water pollution
• Illegal trapping or hunting in localized areas
• Human-wildlife conflict (flooding caused by dams)

Conservation efforts

• Legal protection from hunting and trapping
• Reintroduction and relocation projects
• Wetland restoration efforts
• Educational outreach to reduce human-wildlife conflict

How to help

• Support organizations working on wetland and river habitat conservation
• Advocate for coexistence strategies with landowners and farmers
• Volunteer with local stream or wetland monitoring projects
• Promote education about the ecological benefits of beavers

Beavers facts for kids

Beavers are big, furry animals that live by rivers and build amazing dams and houses out of sticks and mud. They have big orange teeth and flat tails that help them swim! Beavers are very important for nature because they create ponds where many other animals can live.

• Beavers slap their tails to make a loud splash!
• They use sticks and mud to build their homes called lodges.
• A beaver’s front teeth never stop growing.
• Beavers can swim underwater for up to 15 minutes.
• They help other animals by making new ponds and wetlands.

Did you know? Did you know? Beavers are sometimes called 'nature’s engineers' because they can change whole landscapes with their dams!

Watch & learn

• Beaver Superpowers: Nature’s Engineers — BBC Earth. This documentary segment dives deep into the beaver’s impressive dam-building abilities, exploring how their engineering skills reshape entire landscapes and benefit ecosystems.
• Leave It to Beavers: The Comeback of Castor canadensis — PBS Nature. Uncover the fascinating ecological importance of North American beavers as PBS Nature follows their reintroduction to habitats and the positive impact on biodiversity.
• Castor: Beavers Transforming the Wild — Smithsonian Channel. Witness stunning footage of beavers at work as Smithsonian Channel explores how their behavior and unique adaptations as semi-aquatic rodents change rivers and forests to support life.
• Beavers: The Land Engineers — National Geographic Wild. See beavers’ construction strategies up close, with dramatic visuals of dam and lodge building, plus discussion of their impact on other animal species and freshwater habitats.
• Wild Canada: The Secret Life of Beavers — BBC Earth. Follow a beaver family through the seasons in a Canadian wilderness, observing intimate moments and natural challenges in their daily life.