# North American Beaver (*Castor canadensis*)

> The North American beaver is a large rodent that fells trees and builds dams and lodges, creating wetlands that benefit fish, birds, and other wildlife. Adults weigh 16–32 kg (35–70 lb), have webbed feet and a flat tail, and can stay underwater for up to 15 minutes.

- **Category:** Mammal
- **Conservation status (IUCN):** Least Concern
- **Range:** Rivers, lakes, and ponds across Canada, the United States, and northern Mexico; reintroduced to parts of Europe where the Eurasian beaver also occurs.
- **Canonical page:** https://globalanimalguide.org/animals/beaver/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Mammalia
- **Order:** Rodentia
- **Family:** Castoridae
- **Genus:** Castor

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Castor canadensis |
| Diet | Herbivore — bark, twigs, aquatic plants, and roots |
| Habitat | Rivers, lakes, and ponds across North America |
| Lifespan | 10–20 years in the wild |
| Weight | 16–32 kg (35–70 lb) |
| Top speed | Up to 55 km/h (34 mph) swimming; clumsy on land |
| Conservation status | Least Concern (IUCN) |

## Dam building

Beavers cut trees with powerful incisors and weave branches into dams that raise water levels, protecting lodge entrances and creating ponds. These wetlands filter water, reduce flooding downstream, and provide habitat for hundreds of species — beavers are considered ecosystem engineers.

## Lodges and family life

Beaver families live in dome-shaped lodges with underwater entrances. Kits are born in spring and stay with parents for up to two years, helping maintain dams and learn construction skills. Castoreum from scent glands marks territory.

## Recovery from trapping

Beavers were trapped nearly to extinction for fur hats in the 1800s but rebounded after protection and reintroduction. Today they are Least Concern, though conflicts with landowners over flooded roads and timber prompt relocation or flow-device management in many states.

## Keystone role

By slowing water and creating ponds, beavers increase biodiversity, store carbon in sediments, and improve drought resilience. Reintroduction projects in the UK and Europe aim to restore these benefits after centuries of local extinction.

## Frequently asked questions

### Why do beavers build dams?

Dams raise water around lodge entrances, making predators harder to reach and giving beavers safe access to food stores in winter.

### How long can beavers hold their breath?

Up to about 15 minutes underwater, aided by transparent eyelids and valves that close ears and nostrils.

### Are beavers rodents?

Yes — beavers are the second-largest rodents after capybaras, in the family Castoridae.

### Do beavers eat fish?

No. Beavers are herbivores that eat bark, twigs, and aquatic plants. They do not hunt fish.

### Are beavers good for the environment?

Yes. Beaver wetlands increase biodiversity, improve water quality, and can reduce downstream flooding — reasons for active reintroduction in Europe.

## Sources

- [IUCN Red List — Castor canadensis.](https://www.iucnredlist.org/search?query=Castor%20canadensis&searchType=species)
- [Animal Diversity Web — Castor canadensis. University of Michigan Museum of Zoology.](https://animaldiversity.org/accounts/Castor_canadensis/)

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Source: Global Animal Guide (https://globalanimalguide.org/animals/beaver/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.