Whales and dolphins are the aquatic animals. They are distributed in the aquatic habitat. Whale is the perfectly marine in habitat where as the dolphin is also found in fresh water as well as in marine habitat.  Both whales and dolphins have got stream-lined body with the paddles and flippers as the locomotary organs. They are excellent divers in the aquatic habitat. Whale is the largest animal of nature. But Dolphin is considered to be the intelligent mammal.They show the secondary aquatic adaptation i.e. they were primarily adapted in the terrestrial habitat but in the course of evolution they migrated from the terrestrial habitat to the aquatic habitat and started tom live permanently in the aquatic habitat.