Beaver, no. As most of my students, in my previous life, know, I hate beavers, destroyers of trout streams & bad examples for humans, too busy. But otters, on the other hand, are very cool, funny, inquisitive & good all around non-humans. This is an interesting find.
"But scientists are reporting today that they have uncovered fossils of a swimming, fish-eating mammal that lived in China fully 164 million years ago, well before it was thought that some mammals could have spent much of their lives in water.
The extinct species appears to have been an amalgam of animals. It had a broad, scaly tail, flat like a beaver's. Its sharp teeth seemed ideal for eating fish, like an otter's. Its likely lifestyle — burrowing in tunnels on shore and dog-paddling in water — reminds scientists of the modern platypus.
Its skeleton suggests that it was about 20 inches long, from snout to the tip of its tail, about the length of a small house cat."