The name transient originated from the belief that these Killer Whales were outcasts from larger resident pods. Researchers later discovered that transients are not born into resident pods or vice-versa. The evolutionary split between the two groups is believed to have begun two million years ago. Recent genetic research has found that the types have not interbred for up to 10,000 years. Three Killer Whale types have recently been documented in the Antarctic. Type A looks like a "typical" Killer Whale, living in open water and feeding mostly on Minke Whales. Type B is smaller than Type A. It has a large white eyepatch and a patch of grey colouring on its back, called a "dorsal cape". It feeds mostly on seals. Type C is the smallest type and lives in larger groups than any other type of Killer Whale. Its eyepatch is distinctively slanted forwards, rather than parallel to the body axis. Like Type B, it has a dorsal cape. Its only prey observed so far is the Antarctic Cod. Type B and C Killer Whales live close to the Antarctic ice pack, and diatoms in these waters may be responsible for the yellowish colouring of both types. Research is ongoing whether Type B and C Killer Whales are different species.