Hector's & Maui's Dolphin Factsheet

 Factsheet

  • Hector’s dolphins are the smallest and one of the rarest marine dolphin in the world.
     
  • A marine mammal, they live in the sea but breathe air.
     
  • Hector's dolphin is only found off the coast of New Zealand, which means it is endemic to New Zealand.
     
  • The Hector’s dolphin was named after Sir James Hector, who was the curator of the Colonial Museum in Wellington (now Te Papa). He examined the first specimen found of the dolphin. Sir James lived from 1834 to 1907. He was the most influential New Zealand scientist of his time.
     
  • Of all the dolphins seen in New Zealand waters, Hector’s dolphins are the only ones with a rounded dorsal fin – all other species of dolphin found in New Zealand waters have crescent shaped fins that are more pointed than the Hector's.
     
  • They also have distinctive black markings on their fins, tails, flippers and faces.
     
  • While common dolphins reach about 2.6 metres in length, Hector's dolphins grow to a diminutive 1.2 - 1.6 metres, and weigh about 35 to 50 kilograms (males are smaller than females). They are so small you could fit them into a bathtub!
     
  • Hector's dolphins live for up to 20 years.
     
  • They swim in pairs, or in groups of up to 12.
     
  • Once distributed in waters all around the New Zealand coast line, these very special animals have now declined to just above 7000 individuals and have been fragmented to a degree that threatens their survival.
     
  • Hector’s dolphin is divided into genetically distinct North Island and South Island sub-species:
     
  • Both the South Island Hector’s dolphin and the North Island Maui's dolphin are listed internationally as Species Threatened with Extinction. Maui’s dolphin are listed as “Critically Endangered”, as there are only an estimated 55 individuals left!
     
  • They prefer shallow water (usually less than 100m) and usually stay within a home range of about 30 km of coastline all their lives.
     
  • They feed on fish throughout the water column, including fish that dwell near the seafloor in shallow, often sandy bottomed waters, making frequent short dives to find food, such as flounder, red cod, mackerel, crabs and squid.
     
  • They use echo-location to locate their prey – it’s like seeing with sound. Dolphins send out a stream of high frequency clicking noises and when the sound strikes an object it bounces back and the dolphin can tell by listening what the object is - what kind of fish it is, how far away it is and how fast it is moving. In familiar areas, their echo-location is ‘turned off’, which means they cannot always detect dangers.
     
  • Hector's dolphins are similar to the endangered parrot the kakapo, in that they do not breed very often, which causes problems for the species' survival. Female dolphins only produce one calf every 2-4 years and do not start breeding until they are seven to nine years old. This slow rate of reproduction makes Hector's dolphin populations particularly vulnerable to deaths caused by human activities such as fishing.
     
  • The single biggest threat to Hectors dolphins is gill nets. Dolphins are accidentally caught in nets and drown.
     
  • The lungs of Hector’s dolphin are small, only about the size of human lungs, so they drown in about the same period of time a human would if they get tangled in set nets.
     
  • Hector's dolphin deaths from fishing must be zero to ensure the species' survival. Set nets are banned or heavily restricted in many countries worldwide, including Australia, the UK and USA.