While canoeing at Brush Lake, I spotted a beaver swimming in the water and was surprised at how long the beaver stayed underwater. American beavers (Castor canadensis) are amazing creatures and here are ten reasons why:
1. Beavers are the largest rodent in North America. They are the second largest rodent in the world with the capybara being first.
2. Beavers can swim underwater for up to 15 minutes. They have valves in their ears and nose that close when they dive to seal out water. While swimming underwater they can reduce their heart rate and increase the flow of oxygen to their brain.
3. Beavers have swim goggles and safety googles built in! A set of transparent eyelids allows them to see underwater and provides protection from debris.
4. Beavers can swim up to five miles per hour. Beavers propel themselves with their large, webbed hind feet and use their front feet to carry mud and sticks while swimming.
5. Beavers can gnaw underwater without swallowing water. Beavers close their upper lips behind their four front incisors to gnaw underwater which prevents them from swallowing water and getting splinters in their mouth.
6. A beaver’s front teeth never stop growing! The two pairs of front incisors grow constantly which allows them to gnaw on wood continuously. The orange iron-rich enamel is harder than the layer of soft dentin behind it. The dentin wears down faster than the enamel when gnawing which results in sharp, chisel-shaped incisors.
7. A beaver’s skin remains dry in the water! A combination of dense, woolly underfur and a water-repellent oil applied by the beaver keeps the skin dry.
8. Beavers comb their fur! On each hind foot one nail is split which enables the beaver to comb debris and parasites from its fur. The split nail also allows the beaver to spread a waterproofing oil on its fur.
9. Beavers have a good sense of smell. They can smell a “tasty” tree! They also use scent as a primary means of communication by leaving chemicals on scent mounds. Beavers create scent mounds by piling mud and vegetation together and then marking it with oil and castoreum.
10. A beaver’s big tail is used for more than slapping a warning. The broad, flat tail acts like a rudder while swimming, stores body fat, acts like a tripod leg when the beaver is sitting up gnawing wood, and helps regulate the beaver’s body temperature. The tail is not used for carrying mud or packing it down for lodges or dams.
