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A dolphin is an aquatic mammal of the order Cetacea, which also includes the whales and porpoises.
The word is used in a few different ways. It can mean:
- Family Delphinidae (oceanic dolphins),
- Both Delphinidae and Platanistoidae (oceanic and river dolphins),
- Or all of suborder Odontoceti (toothed whales).
A porpoise (suborder Odontoceti, family Phocoenidae) is distinct from a dolphin.
There are almost 40 species of true dolphin in 17 genera. They vary in size from 1.2 metres and 40 kilos (Heaviside's Dolphin), up to 7 metres and 4.5 tonnes (the Killer Whale which, despite the name, is a dolphin). Most species weigh between about 50 and about 200 kilos. They are found worldwide, mostly in the shallower seas of the continental shelves, and all are carnivores, mostly taking fish and squid.
The dolphin family is the largest in the Cetacea, and relatively recent: dolphins evolved about 10 million years ago, during the Miocene.
List of dolphins
Delphinidae Oceanic Dolphins
- Long-Beaked Common Dolphin, Delphinus capensis
- Short-Beaked Common Dolphin, Delphinus delphis
- Northern Rightwhale Dolphin, Lissodelphis borealis
- Southern Rightwhale Dolphin, Lissiodelphis peronii
- Tucuxi, Sotalia fluviatilis
- Indo-Pacific Hump-backed Dolphin or Chinese White Dolphin, Sousa chinensis; Sousa plumbea
- Atlantic Humpbacked Dolphin, Sousa teuszii
- Atlantic Spotted Dolphin, Stenella frontalis
- Clymene Dolphin, Stenella clymene
- Pantropical Spotted Dolphin, Stenella attenuata
- Spinner Dolphin, Stenella longirostris
- Striped Dolphin, Stenella coeruleoalba
- Rough-Toothed Dolphin, Steno bredanensis
- Bottlenose Dolphin, Tursiops truncatus
- Chilean Dolphin, Cephalorhynchus eutropia
- Commerson's Dolphin, Cephalorhynchus commersonii
- Heaviside's Dolphin, Cephalorhynchus heavisidii
- Hector's Dolphin, Cephalorhynchus hectori
- Risso's Dolphin, Grampus griseus
- Fraser's Dolphin, Lagenodelphis hosei
- Atlantic White-Sided Dolphin, Lagenorhynchus acutus
- Dusky Dolphin, Lagenorhynchus obscurus
- Hourglass Dolphin, Lagenorhynchus cruciger
- Pacific White-Sided Dolphin, Lagenorhynchus obliquidens
- Peale's Dolphin, Lagenorhynchus australis
- White-Beaked Dolphin, Lagenorhynchus albirostris
- Irrawaddy Dolphin, Orcaella brevirostris
- Boto (Amazon River Dolphin,)Inia geoffrensis
- Chinese River Dolphin (Baiji) Lipotes vexillife
- Ganges River Dolphin Platanista gangetica
- Indus River Dolphin Platanista minor
- La Plata Dolphin (Franciscana) Pontoporia blainvillei
See also military dolphin.
External link
Dolphin (or more properly, dolphinfish) is also used to describe a species of fish which is unrelated to the mammal. The name is being used more and more infrequently and is has generally been replaced with the name mahi-mahi to avoid confusion with the mammal, especially since the fish is commonly eaten.