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How Many Teeth Does a Beaver Have? 

Beavers are the lumberjacks of the animal kingdom, and they inhabit forests throughout North America and Europe. They have an irreplaceable impact on their environment because of the valuable ecosystem services they provide. From felling trees to damming creeks and rivers, the effects of their behavior spread outwards from waterways and into the surrounding landscapes.

Thanks to their strong incisors and evolutionary adaptations, beavers can make use of trees for building materials. That leads to the main question of this article. How many teeth do beavers have? Keep reading to learn more.

Key Points:

  • Beavers are some of the largest rodents in the world with some of the most recognizable teeth: four curved upper and lower incisors.
  • There are two species of beavers alive today: the North American Beaver and the Eurasian Beaver. Both kinds of beavers have 20 strong teeth, including 4 incisors.
  • Beavers’ teeth are strong and tough because they contain iron compounds, which increase their gnawing power, prevent tooth decay, and give them an orange hue.

How Many Teeth Does a Beaver Have?

Beaver showing its orange teeth
Beaver showing its orange teeth | image by born1945 via Flickr | CC BY 2.0

Beavers have 20 teeth, all of which continue to grow throughout their lives. As mammals, their teeth are heterodont, meaning that they have different shapes to suit different functions. Beavers have four incisors, four premolars, and twelve molars.

How Many Front Teeth Does A Beaver Have?

A beaver has four front teeth – two on top and two on bottom. These buck teeth, called incisors, are orange-yellow and extremely strong.

Over millions of years, beavers adapted to live in semi-aquatic environments. Their bodies are designed to augment the power of their teeth and improve their dam-building efficiency.

Beavers have a space between their incisors and their remaining molars. This space, called a rostrum, gives them an area where sticks, tree trunks, and limbs can settle into when they hold them in their mouths.

They can also close their lips around their front teeth using the rostrum space. This creates a watertight seal so the beaver can carry wood underwater, avoid splinters, and reduce the amount of ingested water in their bodies. They can even gnaw and bite into things while underwater!

Will a Beaver Bite You?

Beaver in riverbank

Like most animals, a beaver will bite when it feels threatened or cornered. Beavers are territorial and will chase off interlopers from their ponds and dams, but they generally stay away from people.

Bears, mountain lions, wolves, coyotes, foxes, and eagles all eat beavers. A beaver’s first instinct is to hide, but if it can’t get back to its den in time, it may lash out.

A man from Belarus was killed by a beaver when he got too close to it while attempting to take a picture. It bit his leg just once, but the bite severed an artery and unfortunately, the man did not survive.

It is crucial to remember that wild animals are wild for a reason. Human contact is not recommended with wild animals, even herbivores like beavers. While all beavers should be left alone, young males can be especially unpredictable and difficult to fend off.

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How Strong are Beaver Teeth?

Beavers rely on their teeth day in and day out. Beavers’ teeth are so strong that they are able to gnaw through trees in just minutes.

It follows that the composition of the bone, roots, and growth strategy of the teeth would be extremely resilient and strong.

First, beavers’ teeth grow continuously. Beavers are the largest species of rodent in North America, and all rodents have continuously-growing teeth. Gnawing is an integral part of their diet and lifestyle.

If the beaver bites down badly on a limb or tree trunk and breaks a tooth, it won’t starve or die. It simply waits for the tooth to regrow. This might inconvenience it or make it more vulnerable to attacks from predators, but it isn’t a death sentence.

Second, the orange color of beaver teeth is due to the presence of iron in the bone. The iron increases the hardness of the teeth and protects them from decay. The beaver becomes a more efficient gnawing machine.

Iron compounds are only on the front of the incisors, but this doesn’t pose a threat to the beavers. The dentin-covered back surface of the teeth wears away quickly. This creates a sharp angled edge that cuts bark and wood more efficiently.

How Hard do Beavers Bite?

beaver in nature
Beaver in nature | image by Deborah Freeman via Flickr | CC BY-SA 2.0

Beavers have a bite force of 180 pounds per square inch (psi). Compared to carnivores like the alligator (2,980 psi) or lion (650 psi), it’s not much, but it’s certainly more than a human’s paltry bite force of 88 psi.

Beavers are herbivorous, so they have no need to be able to bite the throats of animals or chomp through bones. A bite force of 180 psi is just enough for the tasks a beaver needs to accomplish: breaking off plant matter to eat and gnawing at sticks and the trunks of trees.

How Big of a Tree Can A Beaver Chew Through?

Beavers can take down trees ranging from several inches around to as wide around as 33 inches. Since these large rodents grow to a maximum of three to four feet long and sixty pounds, there is a limit to the size of the tree trunk they can munch through.

Beavers are methodical tree fellers that use tried and true methods to fell trees and drag them back to their dams. They are so in tune with the trees that they are able to make them fall in the direction of their dams over 70% of the time!

The rodents accomplish this feat by gnawing in specific places on the tree in order to reduce its structural stability.

  • First, they cut on the side of the tree facing the water.
  • Second, they make a cut higher up on the opposite side.
  • Third, they wait for the tree to grow unstable and fall.

Beavers are more intelligent than other rodents, and their habitual work with felling trees may hold the key to this evolutionary development.