The Beaver. The pursuit of this animal's fur caused men to spend years in the wilderness, and almost caused the destruction of the species out. Today, there are once again millions of these guys. Some would say too there are millions too many! Yes, they can cause tremendous damage, but they also change some areas for the good of the entire ecosystem. I, for one, am only too happy to sit and watch these guys as they go about being "busy as Beavers"!