How little we know about the ocean is staggering. What little we know and understand about orcas, killer whales, is just one example.
For years, there were thought to be two types of orcas — residents and transients. Residents stayed or returned to one area whereas transients were more wide-ranging. In 1988, scientists discovered a previously unknown type of offshore killer whale. Additionally, three types of Antarctic killers were identified, designated A, B, and C. A fourth type with very different body shape and markings was first seen in a mass stranding in New Zealand in 1955, but had not been seen alive by scientists until just recently. Here is a video about the search for this new type, perhaps a new species, of killer whale, referred to as the Type D.