Dolphins

Dolphins belong to the Delphinidae and, in some cases, Platanistoidea and Odontoceti families. They evolved about 10 million years ago and there are now in existence about 40 types of dolphin, within 17 genera. They differ in size from the 1.2m and 40kg (Maui's dolphin), to the 9.5m and 10 tons (the orca). Many of the dolphin species are known to weigh about 50 - 200 kg and can be found all over the world. One particular species native to the Great Barrier Reef habitat is the rare irrawaddy inshore dolphin. The irrawaddy dolphin has a rounded head with no beak, and a flexible neck. They can vary in colour from dark and light blue-grey to pale blue. It is grouped as an oceanic dolphin and is carnivorous, living off a diet of fish and squid. Irrawaddy dolphins also carry features which are similar to both the porpoise and the beluga whale, and therefore sometimes prove difficult to define. They have a special relationship with the fishermen at the Great Barrier Reef, helping to guide the fish into their nets.