what are cetaceans

Cetaceans are an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. They are known for their fully aquatic lifestyle, streamlined body shape, large size, and exclusively carnivorous diet. Cetaceans propel themselves through the water with powerful up-and-down movement of their tail, using their flipper-shaped forelimbs to maneuver. They have a cartilaginous fluke at the end of their tails that is used for propulsion, and their physiology allows for effective distribution of blood oxygen and maintenance of a nearly constant body temperature. Most cetaceans are social animals, living in groups known as pods, and they are known to teach, learn, cooperate, scheme, and grieve. Cetaceans are entirely carnivorous and are entirely aquatic, meaning they spend all of their time in water. They are warm-blooded, give birth to live young, produce milk, and have hair, all features of mammals. Cetaceans are divided into two distinct types: Mysticeti (baleen whales) and Odonotoceti (toothed whales), with baleen whales being the larger whales and toothed whales including dolphins, porpoises, and beaked whales. Cetaceans have evolved around 50 million years ago and are known for their intelligence and social behavior.