Cetacea and two (external) limbs that are modified into flippers. Though not as flexible or agile as seals, cetaceans can swim very quickly, with the killer whale able to travel at in short bursts and the fin whale able to cruise at . Dolphins are able to make very tight turns while swimming at high speeds. The hindlimbs of cetaceans are internal, and are thought to be vestigial. Baleen whales have short hairs on their mouth, unlike the toothed whales. Cetaceans have well-developed senses—their eyesight and hearing are adapted for both air and water, and baleen whales have a tactile system
Children of the Whales Children of the Whales The story focuses on a boy called Chakuro, who lives on a giant vessel called a Mud Whale that drifts over the sea of sand. In the Mud Whale, society is divided into two kinds of people: the Marked, who can move objects with their minds using a strange power called "thymia", at the expense of shortened lifespans, and the Unmarked, people who lack thymia but enjoy longer lifespans. Chakuro and his friends have never seen anyone from the outside world, and they spend their days yearning to explore and learn about it. In year 93