Hector’s dolphins are endemic to New Zealand. The species is divided into two subspecies, one of which occurs principally in South Island waters (Hector’s dolphin), and the other in the waters of the north-west coast of the North Island (Maui’s dolphin).

Hector’s dolphin is considered to be one of the world’s rarest dolphin species. The Department of Conservation threat status of the South Island Hector’s dolphin is “nationally endangered” and Maui’s dolphin is “nationally critical”. The subspecies also appear on the World Conservation Union (IUCN) Red List as endangered and critically endangered, respectively.

Hector’s dolphins are revered as a taonga by Maori. Tutumairekurai is the most common of the Maori names for Hector’s dolphin, meaning ocean dweller. Some Maori believed that the spirits of the dead would become tutumairekurai. Papakanua, tupoupou, hopuhopu and upokohue were names also used.
 

Three genetically distinct and geographically isolated populations of Hector’s dolphin have been identified on the South Island. These are found on the east coast of the South Island, the west coast of the South Island and the south coast of the South Island. The most recent abundance estimate for the South Island subspecies is 7,270 individuals.