What is a dolphin?All of the whale and dolphin species belong to the order Cetacea. This order is split into two groups. The dolphins belong to the 'toothed whale' group, which also includes the porpoises and some of the 'whales' such as orca and sperm whale. (The other group are the baleen whales, and include most - but not all - of the classic large whales. The toothed whales, including the dolphins, have (as the name suggests), rows of teeth, and generally use these to catch and eat prey, such as fish and sometimes mammals. The size varies considerably; the largest in the family is the Orca, and the smallest is the Hectors, at about a metre in length. Most are generally sleek and torpedo in shape. They usually have obvious dorsal fins and tail flukes, and usually a prominent snout, or at the very least a head that tapers to a point. Most are grey in colour, but many species have bolder patterns of black and white, and this is an important way to identify species. Within this suborder the main family is the Delphinidae. This group has 36 species and includes most of the classic and most familiar species. Some species, such the Bottlenose and the Common, are found all over the world. Other species are more specialized and found in relatively specific regions, such as Hectors Dolphin around New Zealand.
They are very social animals, and some of their pods grow to hundreds of individual animals. The most commmonly seen species in the open waters of the tropical Indo-Pacific would probably be the Spinner (pictured below)
This information includes edited extracts from the book:
"Ocean Surfaces of Australasia"
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