Dolphin — Dolphins are aquatic mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in seventeen genera. They vary in size from 1.2 metres (4 ft) and 40 kilograms (88 lb) (Maui’s Dolphin), up to 9.5 m (30 ft) and ten tonnes (the Orca or Killer Whale). They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating fish and squid. The family Delphinidae is the largest in the Cetacea, and relatively recent: dolphins evolved about ten million years ago, during the Miocene. Dolphins are considered to be amongst the most intelligent of animals and their often friendly appearance and seemingly playful attitude have made them popular in human culture.
Oceanic dolphins are the members of the Delphinidae family of cetaceans. These aquatic mammals are related to whales and porpoises. They are found worldwide, mostly in the shallower seas of the continental shelves. As the name implies, these dolphins tend to be found in the open seas, unlike the river dolphins, although a few species such as the Irrawaddy Dolphin are coastal or riverine.
Six of the larger species in the Delphinidae, the Orca and the Pilot, Melon-headed, Pygmy Killer and False Killer Whales, are commonly called whales, rather than dolphins. They are also sometimes collectively known as “blackfish”.
The Common Dolphin is the name given to up to three species of dolphin making up the genus Delphinus.
Prior to the mid-1990s, most taxonomists only recognised one species in this genus, the Common Dolphin Delphinus delphis. Modern cetologists usually recognise two species – the Short-beaked Common Dolphin, which retains the systematic name Delphinus delphis, and the Long-beaked Common Dolphin D. capensis. Despite its name the common dolphin is not the dolphin of popular imagination – that distinction belongs to the Bottlenose Dolphin, largely due to the television series Flipper.