Dolphin in ocean
Dolphins are marine mammals closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from 1.2 m and 40 kg, up to 9.5 m and 10 tonnes (the orca or killer whale). They are found worldwide, mostly in the shallower seas of the continental shelves, they are carnivores, eating mostly fish and squid.