Scientific Classification: Order & Genus. The scientific order of all types of whales is Cetacea. This large order is broken down into three further groups as well: the toothed whales or Odontoceti, which includes killer whales, dolphins, porpoises, beluga whales, and sperm whales, the baleen whales or Mysticeti, which include blue whales, humpback whales, gray whales, and right whales, and the Archaeoceti order, which are all now extinct. The genus of these species is Orcinus orca. Family. The killer whale is the largest in its family of delphinid. Bottlenose dolphins, common dolphins, and Pacific white-sided dolphins are included in this group as well. The scientific name for this family is Delphinidae. Fossil Record. Modern forms of both odontocetes and mysticetes can be seen in the fossil record of five to seven million years ago. Scientists believe that early whales arose about fifty-five to sixty-five million years ago from, now extinct, ancient land mammals that happened to venture back into the sea. Habitat And Distribution: Distribution. Killer whales can be found in all oceans of the world. They are the most numerous in the Arctic Ocean and the Antarctic. However, their distribution is limited by seasonal pack ice. Habitat. The main living environment for killer whales is open oceans but they can also be found in coastal waters as well. Migration. Killer whales are very important in the oceans because they cause much of the migration of many fish and other prey. The movements of the killer whale to and from certain areas cause the other prey to move as well. Population. The worldwide population of killer whales is unknown, however they are not endangered whatsoever. Specific populations in a few areas have been estimated in recent years and some areas of the Antarctic alone have about 180,000 killer whales. The population can be distinguished because killer whales travel in pods, or groups.