Dolphins and whales are marine mammals. Like us, they breathe air, are warm-blooded, give birth to live young and nurse them with milk.
Whales, dolphins and porpoises are known as cetaceans. They belong to the scientific order of Cetacea, which comes form the Latin word cetus meaning ''large sea creature''.
Scientifically, all cetaceans are whales, but smaller whales are referred to as dolphins, and one family of small whales, are known as porpoises.
Around the world there are more than 80 species of cetaceans, almost half of which are found living or moving through New Zealand waters. Find out more about these animals - from the world's smallest dolphins to the world's largest whales - below: