What color are the beavers' fur?

Beavers have orange teeth. Wierd, I know! But when they are born they're teeth are white and very soft and not strong at all. But as they get older they start to chew on trees, and logs, and other bigger stuff like that, and accually those kind of things have iron in them. So, when the beaver chews on all tose things it get iron all over their teeth. Then, when they get in the water and swim all the time it makes the iron turn to orange.