Dolphins

Dolphins are marine 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 m (4 ft) and 40 kg (90 lb) (Maui's dolphin), up to 9.5 m (30 ft) and 10 tonnes (9.8 LT; 11 ST) (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 Cetacean order, and evolved relatively recently, about ten million years ago, during the Miocene. Dolphins are among the most intelligent animals, and their often friendly appearance and seemingly playful attitude have made them popular in human culture. 

 

Etymology

The name is originally from Greek δελφίς (delphís), "dolphin",^[1] which was related to the Greek δελφύς (delphus), "womb".^[2] The animal's name can therefore be interpreted as meaning "a 'fish' with a womb".^[3] The name was transmitted via the Latin delphinus^[4] (the romanization of the later Greek δελφῖνος - delphinos^[5]), which in Middle Latin became dolfinus and in Old French daulphin, which reintroduced the ph into the word. The term mereswine has also historically been used.^[6]

The word is used in a few different ways. It can mean:

• any member of the family Delphinidae (oceanic dolphins),
• any member of the families Delphinidae and Platanistoidea (oceanic and river dolphins),
• any member of the suborder Odontoceti (toothed whales; these include the above families and some others),
• and is used casually as a synonym for bottlenose dolphin, the most common and familiar species of dolphin.

This article uses the second definition and does not describe porpoises (suborder Odontoceti, family Phocoenidae). Orcas and some closely related species belong to the Delphinidae family and therefore qualify as dolphins, even though they are called whales in common language. A group of dolphins is called a "school" or a "pod". Male dolphins are called "bulls", females "cows" and young dolphins are called "calves".

Mythology 

Dolphins have long played a role in human culture. Dolphins are common in Greek mythology and there are many coins from ancient Greece which feature a man or boy or deity riding on the back of a dolphin.^[58] The Ancient Greeks welcomed dolphins; spotting dolphins riding in a ship’s wake was considered a good omen. In Hindu mythology, the Ganges River Dolphin is associated with Ganga, the deity of the Ganges river. 

Popular culture 

In more recent times, the 1963 Flipper movie and the subsequent 1964 television series, popularized dolphins in Western society. The series, created by Ivan Tors, portrayed a dolphin as a kind of seagoing Lassie. Flipper was a Bottlenose Dolphin who understood commands and always behaved heroically. Flipper was remade in 1996. In the 1990s science fiction television series seaQuest DSV featured a bottle-nose named Darwin who could communicate using a vocoder, a fictional invention which translated clicks and whistles to English and back. The 1993 movie Free Willy made a star of the Orca playing Willy, Keiko. The 1977 horror movie Orca paints a less friendly picture of the species. Here, a male Orca takes revenge on fishermen after the killing of his mate. The 1973 movie The Day of the Dolphin portrayed kidnapped dolphins performing a naval military assassination using explosives. This was also explored in the similarly named Simpsons Treehouse of Horror episode, Night of the Dolphin, where Lisa frees a dolphin at a aquarium attraction and unwittingly initiates their plan to overthrow the land-dwellers and live in their place. In The Hitchhiker's Guide to the Galaxy series, dolphins are the second most intelligent species on Earth (after mice). 

http://en.wikipedia.org/wiki/Dolphin