The beaver is the largest rodent in North America (and the second-largest in the world after South America’s capybara). They are found in ponds, lakes, rivers, marshes, streams and adjacent wetland areas throughout the U.S. and Canada, with the exception of the California and Nevada deserts and parts of Utah and Arizona.

These quirky creatures have short, stocky bodies with a yellow-brown to almost black coat and a broad, flat, scaly tail. A beaver’s long, dark-orange, self-sharpening incisors grow nonstop throughout its lifetime and need to be worn down through daily use. If not, they can prevent the beaver’s mouth from closing enough for its grinding molars to meet, which can lead to malnutrition or even starvation.

As one of the few species that significantly modify their environment, beavers put their unique teeth to great use. By building watertight dams, beavers reduce stream erosion as they form slow-moving ponds that provide habitat for dozens of species.

Beavers have webbed rear feet and digitated front paws that help them regularly move between aquatic and terrestrial environments. On land, they are pretty awkward, making them vulnerable to predators. But in water, beavers can swim up to 6 mph and stay submerged for up to 15 minutes!

Despite their resourcefulness, these talented and productive animals almost went extinct about a century ago. Read on to find out how the colonization of North American by European settlers threatened to put the industrious beaver out of business, and how they’ve gnawed their way back from the brink. 

A Conservation Success Story

When the first white European colonizers arrived in North America in the late 1400s and early 1500s, there were as many as 400 million beavers (Castor canadensis) spread across the continent. But by 1900, the species was nearing extinction. For centuries, beavers they were trapped for their pelts, as their water-resistant furs made for some very warm items. Their thick fur was transported across Canada and New England for manufacture into coats, shawls, blankets and hats. They were even traded in China for tea and spices.

1890s Colin Fraser, trader at Fort Chipewyan (Alberta), sorts fox, beaver, mink & other precious furs. Alberta Canada

1890s fur trader at Fort Chipewyan (Alberta, Canada). Photos by C.W. Mathers and Ernest Brown.

Beaver fur was so in-demand that the animal is often touted as the very reason Canada exists. Between 1826 and 1834, Hudson’s Bay Company trappers in present-day northeastern Washington killed an average of 3,000 beavers per year. Around the same time, the European species (Castor fiber) faced a similar sad plight, dropping to just 1,200 individuals.

Thankfully, in the early 1900s, the fur trade went out of vogue. The American population skyrocketed, and today, there are an estimated 15 million beavers in North American waterways.

Skull and fur of European beaver (Castor fiber) in Rur river in North Eifel territory of Eifel Region in Germany, Europe

Skull and fur of European beaver (Castor fiber) in Rur river in North Eifel, Germany.

Why Do Some People Still Want to Eradicate Beavers?

To some, the beaver is an important symbol of North America’s diverse wildlife. Others revere the animal for its productivity. (You’ve no doubt heard the phrase “busy as a beaver!”)

To others, though, the beaver is simply a pest to be dealt with. Over the years, this bucktoothed critter has gained a bad reputation among landowners for its tendency to chew down trees and craft intricate dams capable of stopping a rushing river and flooding agricultural land. 

A beaver in the forest eating, closeup

Although people sometimes complain about beavers chewing down trees, they actually create more habitats than they destroy. Landowners have also voiced fears that beavers can damage valuable salmon stocks in local rivers. Beavers don’t eat fish—though plenty of people think they do—and landowners mistakenly imagine their dams could cause problems.

Want to learn more? We discuss the unfortunate reputation of the beaver in detail on this episode of our Daily Dose of Nature Webinar.

What Roles Do Beavers Play in Their Ecosystems?

Not only do beaver-built waterworks create habitats for wildlife, but they also improve water quality and mitigate the threats of climate change, such as drought and flooding. American Indians referred to the beaver as the “sacred center” of the land, because this magnificent critter creates such rich, watery habitat for other mammals, fish, turtles, frogs, birds and ducks.

Two beavers sitting on top of their nest dam site in autumn

“They are the quintessential ecosystem engineers,” says ecologist James Byers of the University of New Hampshire. “And they’ll do this work for free.”

Beavers prefer to dam streams in shallow valleys, where the flooded area gets turned into productive wetlands. These cradles of life support a level of biodiversity that rivals that of tropical rain forests. In the American West, for example, wetlands cover just 2% of the total land area but support about 80% of the biodiversity. Almost half of the endangered and threatened species in North America rely upon wetlands, and freshwater wetlands have been rated as the world’s most valuable land-based ecosystem.

Huge beaver dam along a hike in Alaska

Beaver dam in Alaska.

Beavers reliably and economically maintain wetlands that sponge up floodwaters, alleviate droughts and floods (because their dams keep water on the land longer), lessen erosion and raise the water table. Wetlands act as firebreaks and also as the “earth’s kidneys” to purify water. The latter occurs because several feet of silt collect upstream of older beaver dams. Here, toxins like pesticides are broken down by microbes in the wetlands that beavers create. This means that the water downstream of beaver dams is cleaner. One study in Utah found that restoring beavers to a single river basin produced tens of millions of dollars in economic benefits each year.

Beaver Restoration and Conservation

Methow Valley

One of the most ambitious beaver restoration projects is taking place in central Washington’s Methow Valley. Located on the east side of the Cascade Range, it’s a dry place with a lot of wildfires. And the problem is only getting worse, as snowpack and glacial melt from the Cascades declines due to global warming. The Methow Valley is one of the country’s largest apple- and hop-growing regions, so water is especially critical for the area’s agricultural production.

In addition to water shortages, farmers and landowners struggle with beaver conflicts. In their dam-building efforts, the creatures sometimes chew down both fruiting and ornamental trees, as well as other agricultural products such as alfalfa. They’ve also been known to flood roads, pastures and even homes.

The Methow Project traps and removes beavers from private land—where they’re often considered a nuisance—and relocates them to headwater streams on public lands higher in the mountains. By building dams and creating ponds in their new locales, the beavers keep rivers and streams in Central Washington wet throughout the entire year. In this way, the beavers function as a climate adaptation strategy, helping compensate for the loss of snowpack and glacial melt.

Momma and baby beaver chewing branches And swimming in water

Puget Sound

Meanwhile, on the Puget Sound, beavers are being reintroduced to enhance salmon stocks. These are especially important for Native American tribes in the Pacific Northwest. Baby salmon don’t want to live in the main channel, because while they are so little they can get blown downriver. They thrive in a nice, slow-water habitat, like a pool or backwater. Here, they can get out of the current and go after food without expending too much energy. By slowing the waters down, beavers create that ideal baby salmon habitat.

The United Kingdom

Conservationists are also working on restoring beaver populations across the Atlantic. Beavers were completely wiped out in Britain by the late 1700s. But in the last few years, there have been a number of reintroduction efforts, moving beavers from Germany and Norway and relocating them to England and Scotland. Britain is a rainy place with lots of flooding issues, but a research team from Devon has shown that beaver dams absorb up to 30% of the water during a typical big rain, making for impressive flood-damage reduction.

Where Can I See Beavers in the Wild?

We keep an eye out for beavers on most of our U.S. National Parks and Canada and the North trips. Autumn is the most active time of year for beaver as they gather and store their winter food supplies. Beavers are most active at dusk and dawn, when can sometimes spy them cutting branches from trees, dragging them into the water and anchoring them in the mud near their lodges for later use. Not only are the beavers fascinating to observe, but their ponds are magnets for other wildlife as well.

Want to learn more and perhaps question some of your own current beliefs about what you know about wildlife? Our Daily Dose of Nature webinars occur every weekday at 1 p.m. Mountain Time and are engaging and educational webinars from our 150 guides from around the globe. We would love to connect with you there!

Beaver couple meets lovingly on a stone.