The Rhinoceros Auklet, Cerorhinca monocerata, is a seabird considered, despite its name, a close relative of the puffins. It ranges widely across the North Pacific feeding on small fish and nesting in seabird colonies. Its name is derived from a horn-like extension of the beak. This horn is only present in breeding adults, and like the elaborate sheath on the bill of puffins is shed every year.