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Wildlife Wednesdays: The American Beaver

Did you hear that someone stole a bunch of prime timber?

Authorities eventually tracked it down to a group of beavers. Not everyone was convinced, but the evidence was damming.

The American Beaver, or Castor canadensis, is the largest rodent in North America and the second largest in the world, behind the Capybara of South America. They are largely nocturnal animals, doing most of their “busy” work over 12 hours through the night keeping up their territories.

Since they are quite elusive to us during the day, we’d like to give you some clues to identify a beaver’s territory when you come across it.

Tree cut by beaver teeth. The cut is in the shape of a heart.

Felled Trees

Felled trees, like the example pictured above, are probably the easiest identifier of beaver activity. Using only their four front teeth, Beavers can down a small tree within a few minutes. While they will cut larger trees they have learned to use the wind to their advantage by chewing the base just enough to let the breeze take over. Along with these gnawed-off stumps, beaver slides (the tracks of a tree dragged through the mud) are usually nearby.

Beaver Tracks

The next clue you might spot would be their unique tracks whose front and back feet are different sizes and shapes. The front feet are usually around 2 to 3 inches long while the hind, webbed feet come in at around 6 to 7 inches long! Compare to other common Maryland critters here.

Castor Piles

Getting closer to a Beaver’s home you might see some curious castor piles. These piles, made of mud and plant materials, are scent markers for a Beaver’s territory and are often found surrounding a pond or river’s edge where a dam or lodge is nearby. There can be hundreds of these mounds per lodge depending on how close their neighbors are so be careful not to step on these stinky landmines.

Warning Slap

If you are lucky to see a Beaver near its home you may get a warning slap. When threatened, Beavers will slap the water with their tails which is thought to scare off potential predators and possibly warn family members that there is danger nearby. Check it out here.

Dams and Lodges

Finally, you might come across the exquisite engineering feats of the American Beaver, dams and lodges.

A lodge is a large mound made from mud and sticks with an underwater entrance where a life-long couple may spend their time sleeping and raising young.

A dam is multifunctional, calming river flow to prevent lodges from getting swept away as well as deepening and widening the waters of their territory to encourage new wetland plant growth which eventually encourages more wildlife to show up such as fish and birds.

The beneficial impacts of beaver dams are staggering. They can reduce erosion, decrease flood damage downstream, filter impurities from reaching lakes, increase nutrients, encourage riparian growth, and provide crucial habitats for other wildlife.

However, they have been known to build their dams in problematic areas causing damage to farmland and privately owned homeland, but we’ll let you be the judge on what that means for Maryland’s ecosystem.


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