Melon-headed whale

The Melon-headed Whale ("Peponocephala electra") is a mammal of the oceanic dolphin family. 
It is closely related to the Pygmy Killer Whale and the Pilot Whale. These dolphin species are known by the common name "Blackfish". The Melon-headed Whale is widespread throughout the world's tropical waters, although it is not often seen by humans because it prefers to live in deep water.