Over 75 species of mammals occur in the range, including the mountain goat that lives in the high alpine tundra. Bird species include the bald eagle, osprey, and harlequin duck. Examples of amphibians occurring in the North Cascades include the western toad, Bufo boreas, and the rough-skinned newt, Taricha granulosa. An unusual feature of the rough-skinned newt populations is that approximately ninety percent of the adult population is perennibranchiate.