Answer:
Both the porpoise and dolphins are categorized in similar mammalian order Cetacea. Both exhibit streamlined body, their hindlimbs are vestigial, forelimbs got modified into flippers, and both primarily eat fish.
The porpoises and dolphins are evolutionarily closely associated as both are toothed whales, in comparison to another group of Baleen whales. All the individuals of Cetacea are the progenies of terrestrial ungulates. The primitive ancestors first originated into the sea about fifty million years ago, and about 35 million years ago, there took a partition in the two distinct lines, of these the toothed whales established a strong sense of echolocation.
