Beaver

The beaver is one of the few other creatures that build their homes, rather than us humans. Oh and paper wasps. And termites. And did you know that the outer layer of those big teeth is much stronger than the back of the teeth? So every time a beaver cuts down a tree, its teeth just get sharper and sharper. And guess what? They can make their own ecosystem, because they make those dams. So many creatures can come to the lake, like bass and otters, many different types of frogs, and of course, good old ducks, like the wood duck. And here's the warning signal: when a beaver sights danger, they slap their tails on the water and hopefully many other beavers hear it so they can hide from the danger. Now you might think they just use sticks, sticks, sticks - well if they only used sticks, the dam would bust open and there would be many leaks. But instead they also use mud, to, you know, make the walls nice and secure. And you may think that beavers eat the wood, like their work is also their food - well, it's something like that. Now they don't eat bark, they eat an inner layer of bark. And how a beaver knows where his last work was: he can make a beaver trail.  And hey, those beaver teeth never stop going. If they didn't get worn out by all that chewing wood, ooh, boy - they're teeth would be pretty long.

(photo from animal.discovery.com)