Killer whale (Orcinus orca) at the surface at sunset. Killer whales are not whales, but dolphins. They are found throughout the world's seas, mainly in coastal areas. They can reach up to 9 metres in length and the male's fin can be up to 2 metres tall. They are social animals living in groups, or pods, that can number up to 40 individuals. They are ferocious predators and tend to hunt in packs, often displaying advanced strategies and forward planning. They eat a varied diet, comprising fish, squid, birds and other marine mammals. Photographed in the Gulf of California, Mexico.