Dolphins are cetacean 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  (Maui's dolphin), up to 9.5 m  and 10 tonnes  (the orca or killer whale). 


A rescued dolphin in Sea world , Gold Coast , Queensland, Australia. image: R.Conan-Davies

Class: Mammalia
Order: Cetacea
Suborder: Odontoceti

  • Delphinidae
  • Iniidae
  • †Lipotidae
  • Platanistidae
  • Pontoporiidae

They are found worldwide, mostly in the shallower seas of the continental shelves and are carnivores, eating mostly fish and squid. 

The family Delphinidae, the largest in the order Cetacea, evolved relatively recently, about ten million years ago during the Miocene.


Fresco of Dolphins, ca. 1600 BC, from Knossos, Crete. image: wikipedia

Origin of the name

The name is originally from Greek δελφίς (delphís), "dolphin”, which was related to the Greek δελφύς (delphus), "womb”. The animal's name can therefore be interpreted as meaning "a 'fish' with a womb”. 

click image for larger size. image: WikipedianProlific/wikipedia

Source: adapted from
Dolphin. (2014, November 15). In Wikipedia, The Free Encyclopedia. Retrieved 07:15, November 23, 2014, from