These grooves enable them to expand during huge intakes of water during 'filter feeding'. Individual humpbacks are identified by their fluke patterns. 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.