On fall day a canoeist rounds a bend in a slough, surprising a swimming beaver. The beaver does what beavers do, it smacks the water with its tail and disappears beneath the surface. That's a warning to other beavers that an intruder is about.
Beavers once pulled another kind of disappearing act on a much larger scale. Beavers are abundant in Alaska, and centuries ago, they were abundant throughout North America, Europe and northern Asia - but that changed. Beavers have long been valued for their fur and for castoreum, a waxy secretion that was used to make perfume and medicine. A desire for pelts and castoreum, and more importantly, competition for habitat, contributed to their disappearance from Europe.
Beavers were once found throughout Europe as far south as Spain and Italy, but disappeared as people claimed the river valleys for agriculture. Beavers disappeared from England in the 13th century. Even the remoter regions of Europe such as Norway, Sweden and Siberia saw the decline of beavers, and by the 1800s, beavers were essentially gone from Europe.
There was no shortage of beaver pelts, however, as the Hudson Bay Fur Company was exporting more than 200,000 pelts a year from North America. By the dawn of the 20th century, the beaver was nearly gone from North America as well.
Since the 1930s, widespread conservation efforts have led to a return of the beaver to much of its former range in America. A small population of beavers in Norway, protected on private land, increased as Norway extended protection to beavers throughout the country. Russia imported beavers from Norway and from America, began captive breeding, and re-introduced beavers, as did Finland and Sweden. Beavers made something of a comeback in Europe, and these animals are a mix of the American and the original European species.