Whale

Whales are mammals whose ancestors lived on land. The move back into water did not abolish gravity or chemistry; it changed how those forces are felt. At depth, pressure rises about one atmosphere every ten meters.

A whale is also a record of evolution: vestigial pelvis, bone, milk, warm blood, and a body shaped by fluid resistance. Other ocean lives on the map lean toward Whale when they are vast, deep, or mammalian. Dolphin is the nearer cousin.