The beluga whale is an Arctic and sub-Arctic whale. It is known simply as the beluga, but is also referred to as melon head or sea canary, due to its high-pitched twitter. It is one of two members of the familyMonodontidae, along with the narwhal, and the only member of the genus Delphinapterus. It is specifically adapted for life in the Arctic. It is all white in color, has a higher percentage of blubber, it has a highly developed sense of hearing, and it also possesses echolocation for detecting blowholes in the ice. They are generally between the size of a dolphin and a true whale, with males reaching up to 18 feet long and 3,500 lbs. They are slow swimmers, but can dive up to 2,300 feet. Their diet consists mainly of fish, crustaceans, and deep sea invertebrates.