Ask most people which dolphins live in Hawaiian waters, and the answer you will almost always hear is spinner dolphins. The spinners are there, and they are remarkable, but Hawaii is home to more cetacean species than most visitors ever realize. One of the more unusual is a deep-ocean animal that most people have never heard of. The rough-toothed dolphin lives year-round in the offshore waters around the Hawaiian Islands, and it looks, behaves, and lives so differently from everything else out there that spending a few minutes learning about it changes the way you see the ocean.