Cetaceans (from Latin: cetus, lit. 'whale', from Ancient Greek: κῆτος, romanized: kētos, lit. 'huge fish', sea monster) are aquatic mammals constituting the infraorder Cetacea (). Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel themselves through the water with powerful up-and-down movement of their tail which ends in a paddle-like fluke, using their flipper-shaped forelimbs to maneuver.While the majority of Cetaceans live in marine environments, a small number exclusively reside in brackish water or...