The European beaver is currently an endangered species. It was hunted almost to extinction. This was done because of its fur, and because of castoreum. Castoreum is made by a certain gland, which is also responsible for the smell of the animal. People are currently (2007) reintroducing the beaver, because the important role of the beaver for the ecology of rivers was discovered. Beaver dams (or the small lakes that form) provide a habitat for many species.