Slap!

In the thousands of hours of wildlife documentaries I have watched in my lifetime, I don't recall ever seeing any footage of a beaver slapping the water with its tail - nor have I seen a photograph of that tail up close. I offer the photos above and a video here. They slap their tails to signal alarm and although they have poor vision, their finely tuned ears pick up the sound above and under the water.

Beavers (using the appropriate definition, of course) come in 2 varieties: North American and European, and are the 2nd largest rodents in the world - although the Roman Catholic Church ruled it a "fish" in the 17th c., so that it could be eaten on Fridays. In addition to their value as a food source, beavers were trapped for their pelts (used to make coats) and for their secretions (used to make perfume). The animals mate for life, but the 2 species cannot interbreed.

I do remember swimming in a river in Connecticut as a teenager and seeing a beaver swimming along the opposite shore, but all that was visible was its head. Speaking of heads, the beaver skull in my bones collection (which happens to be my Mom's favorite) is notable for its big orange teeth, which they have to wear down by gnawing or they will continue to grow. They eat and build dams with the trees they cut down. But their favorite food is lily pads.