There was a time when beaver pelts were in high demand for hats and such. The man with many pelts could count on rich rewards when he sold them. But times change, hats which were once made of beaver pelt were then being made out of silk and there was no longer a demand for the pelts. As a result, prices offered dropped substantially and the trappers who trapped beaver had to look elsewhere to make a living. Nothing is forever except the mighty Dao.