How Dangerous Is the Beaver?

With their oversized front teeth, beady little eyes and funny flat tails, beavers look less like crazed killers and more like the goofballs of the woods. Yet with their distinctive orange-colored incisors, these furry wonders can slash through a finger-sized tree branch with just a single chomp. So that begs the question: Are beavers dangerous to humans?

It turns out that yes, in certain circumstances, beavers might harm people and pets.

In 2013, a man in Belarus approached a beaver hoping to capture a picture of it. But he apparently got too close and the beaver managed to inflict a bite that severed an artery in his leg. He promptly bled to death.

In 2018, a Pennsylvania man ventured out onto a kayak when a beaver attacked his watercraft and attempted to climb aboard. He smacked the beaver multiple times with a paddle to no avail — the beaver merely switched targets, instead attacking the man’s young daughter. He was finally able to beat the beaver to death with a stick.

Sometimes, beavers attack because they’re deliriously sick with rabies. That’s happened multiple times in the past few years, including a 2012 incident in which two Virginia girls were ambushed by a rabid beaver. Both girls survived but received rabies treatments.

But the truth is that beaver attacks make great headlines for one reason — they are incredibly rare.

“Beavers in the wild are not considered dangerous,” emails Michael Callahan, president of the Beaver Institute, which works to reduce beaver-human conflicts using non-lethal methods. “Unless they are threatened, the most aggressive behavior beavers will exhibit is slapping their paddle tail on the water to create a loud noise.”

Beavers are the largest rodents in North America, often weighing between 35 and 65 pounds (16 and 30 kilograms). Although they’re clumsy on land, they’re much more graceful in the water, able to swim about 6 mph (10 kph). Thanks to their larger-than-average lungs, they can hold their breath for around 15 minutes, which means they can swim perhaps half a mile (0.8 kilometer) before they need to resurface for air. They spend their days building dams and lodges (for protection against predators and to store food) not dreaming up ways to dismember humans.

You can find beavers everywhere in North American except desert ecosystems. They’re hard at work cutting down trees, moving logs and building a variety of structures in ponds, creeks and lakes. That might be where the expression “busy as a beaver” comes from. Their long incisors continuously grow throughout life, useful since they’re usually chomping at something. Beaver teeth are orange because they are filled with iron, which makes them stronger, than, say, a rat’s. Those iron teeth allow a beaver to cut through a tree.

They’re strictly herbivores — it’s a misconception that they eat fish or other creatures, says Callahan. Parents care for their young until the babies are 2 years old, after which they move out, find lifelong mates, and build expansive lodges that they use for long-term homes. In fact, beavers are one of the few animals that drastically alter their environments, by adding sticks, branches and mud to their dams.

The results are often a win-win for both beavers and other creatures. “Beavers are tremendously beneficial to the environment. They are North American ‘keystone species‘ meaning their presence on the landscape increases biodiversity,” says Callahan. “Beavers build dams to turn streams into ponds. The new habitats created support innumerable plant, insect, fish and animal species, including salmon and other endangered species.”

He also says that beaver ponds also help fight climate change and wildfires, store precious water and recharge ground water aquifers, improve water quality by removing pollutants from the water, and fix eroded stream channels and restore healthy watersheds. “And beavers perform all these valuable ecosystem services for free!” he adds.

Beaver activity, however, sometimes leaves humans exasperated at the prolific nature of these large rodents.

“The dams that beavers build sometimes flood roads or interfere with human development or other land uses,” says Callahan. “Fortunately, 75 percent of beaver-human conflicts can be resolved without needing to trap or kill the beavers.”

Humans have had a profound impact on beavers and their habitats. Some researchers think that there may have been as many as 400 million beavers before Europeans arrived in North America. But fur traders relentlessly decimated beaver numbers, and their pelts were used to make hats, coats and other clothing that was both warm and stylish for the times.

The trappers and hunters were so efficient that they nearly drove the beaver into extinction. Thanks to modern regulations, their populations rebounded. Now, there are roughly 6 to 12 million of these animals in the United States alone.

With careful management, beaver populations should be safe for decades to come, and their conflicts with humans will remain isolated to a few scattered flooding problems.

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