The Fascinating Reason Why Beavers Slap Their Tails

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Beavers are associated with activity and environmental engineering. If you are “as busy as a beaver,” you are getting things done. These aquatic rodents spend most of their time in the water as they can only manage a kind of ungainly waddle on dry land. It’s not surprising, therefore, that most studies and observations of their behavior have been made in rivers, lakes, and streams. In the above video, you can see a beaver demonstrating just how graceful they are in the water. You also get to see a fascinating beaver behavior called tail slapping. Let’s look at exactly what this is and why beavers do it.  

Beavers and Their Environment

North American beavers (Castor canadensis) are the largest rodent species in the United States and the second largest in the world. They have stocky bodies, weigh between 35 and 65 pounds, and are around four feet long. You can spot them throughout North America except for the very north of Canada and the desert regions of the southern United States and Mexico.

Their close relatives, the Eurasian beavers (Castor fiber), look very similar. However, they are generally a little larger and heavier than their American cousins. They were once found throughout Europe and Asia but over-hunting during the 1800s nearly wiped them out. The good news is that modern conservation efforts have resulted in populations being re-established in Russia and many parts of Europe including France, Germany, and Scotland.

Beaver Tails Have Many Uses

Beavers are perfectly adapted for life in water and even have webbed rear feet. They have two thick, oily coats of fur to keep them warm and dry and both their ears and nostrils are valvular. This means that they can be closed when the beaver dives beneath the surface to prevent water from getting in. Their eyes have nictitating membranes – this is a transparent third eyelid. When the beaver dives under the water, it is drawn across to protect the eye. It’s like having in-built swimming goggles!

Another useful adaption is their flat tail which is covered with black scales. Interestingly, the exact shape of the tail is variable and is a family trait passed down through the generations.  The vertebra (back bones) reach to the end of the tail and the rest is made up of muscles and connective fibers. It comes in very useful when the beaver is swimming. By producing a series of rapid undulations, it provides a helpful forward thrust from the rear!

In addition, it acts like a rudder when changing direction and helps with balance when the beaver is in an upright position on land. As if all of this was not enough, it can also be slapped on the water to create the loud splashing sound. Listen out for it in the above video.

The Purpose of Beaver Tail Slapping

To fully explain why beavers slap their tails we need to look at their social structures. They live in colonies of around 8 to 12 individuals and form strong family bonds. Their home is called a lodge, which is essentially a chamber slightly above the water level. Lodges are located on the banks or shore of a stream or lake. Defending their lodge and the family within it is very important to a beaver and they are highly territorial. If they detect the scent of a potential predator or even of another beaver they will warn their family members by slapping their tails. Beaver predators include wolves and coyotes.

This defensive move may look pretty spectacular in the above video but unfortunately, it does not always work. Studies have shown that older beavers often ignore the warning slaps of younger beavers. That said, research has also shown that if the adult female leader of the family slaps her tail, the rest of the group is more likely to take notice!