Bumps on their bodies are known as 'stovebolts' Since 1966 it has been illegal to hunt humpback whales. Mammals have a 4-chambered heart. Mammals, as a rule, bear their young alive. Mammals nurse their young with milk. Mammals, at some stage in their development, have hair.
Mammals maintain a stable body temperate, independent of the external environmental temperature.
Cetacea is the scientific term used to describe the Order of all whales. The Scientific term for the suborder is Mysticeti. Modern forms of mysticetes appear in the fossil record five to seven million years ago. Evolutionary scientists hypothesize that whales arose between 55 and 65 million years ago from now extinct land mammals that ventured back into the sea. Baleen was referred to as 'Whalebone' by whalers who apparently thought it was made of bone material.