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Facts About Hector's and Maui's Dolphins: Animals of Concern

Linda Crampton is a writer and experienced science teacher with an honors degree in biology. She enjoys writing about science and nature.

Unique Dolphins in New Zealand

The Hector’s dolphin and the Maui’s dolphin are found only off the coast of New Zealand. The population of the Hector’s dolphin is estimated to be around 15,000 individuals. The animals are classified as "nationally vulnerable." The critically endangered Maui’s dolphin is thought to have a population of around 54 animals older than a year. The pressure to protect and conserve these marine mammals is becoming intense, especially in the case of the Maui’s dolphin. Its population may require an emergency intervention in order for the animal to survive.

The two animals are subspecies of the same species. They are relatively small members of the order Cetacea, which includes whales, dolphins, and porpoises. The animals look quite similar, but despite this fact there are significant differences between them. They are light grey and have black and white markings. The animals have a uniquely-shaped dorsal fin along their backs. The fin is rounded instead of being sickle-shaped as in other dolphins. It's often said to look like one of Micky Mouse's ears.

New Zealand consists of two sections—the North Island and the South Island. Dolphins can be found by both islands.

Biological Classification of the Animals

Hector's and Maui's dolphins are classified in the same genus and species (the first two parts of a scientific name). Scientists have decided that the genetics and skeleton of Maui’s dolphins are sufficiently different from those of Hector’s dolphins to warrant placing the animals in different subspecies.

The scientific name of the Hector's dolphin is Cephalorhynchus hectori hectori, while the Maui's dolphin is classified as Cephalorhynchus hectori maui. The first subspecies is found in three separate areas around the South Island of New Zealand. The second lives on the west side of the North Island. The animals that are seen in this location are sometimes referred to as Maui or Māui dolphins or as North Island ones.

Physical Features of a Hector's Dolphin

The Hector's dolphin is named after Sir James Hector (1834–1907). Hector qualified as a surgeon but worked mainly as a geologist. He was the first director of the Geological Survey of New Zealand as well as the first director of the Colonial Museum. This museum is now known as the Museum of New Zealand, or Te Papa Tongarewa.

Hector's dolphins are one of the smallest marine dolphins in the world and reach a maximum length of about 1.5 meters (4.9 feet). They weigh between 40 and 60 kilograms (88 to 132 pounds). They are attractive animals.

The animals’ bodies are generally light grey in color but also have black and white areas. Their flippers, dorsal fin, and tail flukes are black, and their face has a black mask. The dorsal flipper is rounded. The pectoral fins are sometimes described as “paddle-like.” The lower surface of the animals is white. A white stripe extends upwards from the lower surface to each side of the body.

Unlike the familiar bottlenose dolphins that are sometimes kept in captivity, Hector's dolphins lack a "beak." The beak is a projection formed by the extension of the jaws beyond the rounded upper head.

The video below was made in 2016 and refers to a previous estimate of the Hector's dolphin population size.

Daily Life of the Cetacean

Hector's dolphins live mostly in shallow water less than 100 meters deep and are found close to the shore. Recent research suggests that more of the animals live further away from the shore than was previously realized, however. The animals live in groups called pods, which consist of two to twelve individuals. Pods sometimes join to form larger groups.

The dolphins feed mainly on fish and squid, which they catch in dives lasting about ninety seconds. Food is caught on the ocean floor, in the water, or at the surface of the water. Like all mammals, the dolphins breathe air and must periodically surface to obtain oxygen.

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Hector's and Maui's dolphins find their prey by echolocation. During this process, an animal emits very high frequency sounds, also known as ultrasonic sounds. The sound waves bounce off solid objects and return to the animal, enabling it to judge the size, shape, distance, and direction of the objects. The animals also produce audible clicks and whistles as they communicate with each other.

Hector's and Maui's dolphins are active, curious, and confident animals. Maui's dolphins have been observed playing with seaweed, blowing bubbles, chasing each other, jumping out of the water, and fighting. Both animals like to swim close to boats. Some Hector's dolphins will swim next to humans in the water.

Reproduction and Lifespan

Hector's and Maui's dolphins are slow breeders. The females don't reproduce until they are about 7 to 9 years of age. They have only one calf (the name for a dolphin baby) every 2 to 4 years. The gestation period is about ten to eleven months. The calf stays with its mother for as long as two years.

The latest research suggests that Hector's dolphins live for around twenty years, so a female may have a maximum of four calves in her lifetime. This slow rate of reproduction means that the death of a few animals could have a serious effect on the population. The New Zealand Department of Conservation (a government organization) says that twenty years is a short lifespan compared to that of other dolphins.

Facts About Maui's Dolphins

Until relatively recently, Hector's dolphins in New Zealand were classified into four groups, including the three groups around the South Island and the group beside the North Island. In 2002, research carried out by Dr. Alan Baker determined that the North Island dolphins were genetically distinct from the South Island ones. The North Island animals were placed in a different subspecies and given the name Maui's dolphins, while all the animals around the South Island continued to be known as Hector's dolphins.

The Maui's dolphin is the most endangered marine dolphin in the world. It isn't the most endangered cetacean, however. Only ten to fifteen vaquitas exist. This species is on the edge of extinction. The vaquita is classified as a porpoise, not a dolphin.

The Maui's dolphin looks very similar to the Hector's dolphin. It has a bigger skull and a slightly longer snout, however. It also has differences in its DNA, the molecule that contains its genes. If the animal becomes extinct, some of the genetic diversity of its species will disappear.

Hector’s Dolphin Numbers

It's thought that close to 30,000 Hector's dolphins lived around New Zealand in the 1970s. This number is greatly reduced today. The IUCN (International Union for Conservation of Nature) says that around 7,381 mature animals exist and classifies the Hector's dolphin population as endangered. This status is based on a 2008 population assessment, however. Thankfully, according the the Department of Conservation and its more recent data, the population is approximately double that of the IUCN's claim, so the situation doesn't seem to be quite so serious today.

Some otherwise useful sources of information still refer to the IUCN's assessment of the animal's status as "endangered." The IUCN is a respected organization. I wish it would update the dolphin's status or if necessary say why it disagrees with other assessments.

Though the status of the subspecies appears to be better than it was in 2008 and its population seems to have stabilized, the dolphins still need some help. Monitoring the number and condition of the animals is important.

A recent population estimate showed that there are only about 54 individuals over the age of 1 year remaining. There is 95% certainty that this number is between 48 and 64.

— Department of Conservation, New Zealand, with respect to the Maui's dolphin

Maui’s Dolphin Numbers

In the first edition of this article, the Maui's dolphin population was estimated to be approximately 63 animals over the age of one. This is now considered to be very close to the upper limit of the population size. As the quote above says, the New Zealand's Department of Conservation suspects that only around 54 adults exist. The number of calves is unknown.

The estimated population of the Maui's dolphin is so small that the loss of even one animal would be a serious event for the subspecies. The animal's population is classified as critically endangered by all of the sources that I've seen, including the New Zealand Department of Conservation. "Critically" endangered means that the animals are in serious danger of extinction.

Threats: fishing, toxoplasmosis and other disease, oil and gas exploration, boat strike, mining, tourism, noise

— Department of Conservation, New Zealand, with respect to both subspecies of Cephalorhynchus hectori

Population Threats

Entrapment in Fishing Nets

The biggest threat to both dolphins is fishing by set (gill) nets and trawling nets. The animals seem to have difficulty detecting gill nets, which generally have a fine mesh. It's possible that the mammals can detect the nets but find the source of trapped fish worth any risk in approaching them. Another contribution to the problem might be that they use echolocation only some of the time while they're swimming. The Department of Conservation (DOC) says this is a possibility with respect to Maui's dolphins.

Maui's dolphins live closer to shore than Hector's dolphins, making them more susceptible to danger from fishing nets. The animals become entangled in the mesh of the nets. This stops them from reaching the surface to breathe and causes them to drown.

Boat Strikes

Some dolphins are struck by boats. Youngsters are particularly susceptible to being damaged by boat propellers because they swim more slowly than adults and also tend to swim closer to the surface of the water. Pollution and coastal developments hurt the dolphins' population as well.

Mining Activities

Another potential danger for Maui's dolphins is seabed mining in the area where they live. A marine mammal sanctuary has been established in the area, however. Seabed mining is prohibited close to shore within the sanctuary. Set nets and trawling nets are also prohibited close to shore.


When I wrote the previous edition of this article, the DOC stated “disease” as a cause of the dolphins’ problems. They have now become more specific, as the quote above shows. Toxoplasmosis is an infection caused by a single-celled microbe called Toxoplasma gondii. The microbe infects other mammals as well as dolphins, including humans. In us, it may not cause problems except in people with specific pre-existing conditions. This limitation is not the same for all mammal species that are infected.

Some people might think that losing the Maui's dolphin would be sad but not tragic because the similar South Island dolphins still exist. Even if people support this idea, the situation is still serious because the South Island subspecies is also a concern with respect to its population size.

Conservation of the Animals

The restrictions that have been put in place to protect the Maui's dolphin sound like a good beginning. Some conservationists who are familiar with the area where the dolphin lives are unhappy, however. They say that the protection measures don't cover enough of the animal's habitat. The conservationists are pressing for new fishing regulations. The fishing industry says that the livelihood of their workers is threatened by the proposed regulations because the rules would reduce their catch.

The debates and disagreements are taking up valuable time that is needed to prevent the extinction of the Maui's dolphin and allow its population to increase. I think that protecting both of the subspecies of Cephalorhynchus hectori is important. I hope a compromise is reached that is acceptable for conservationists and the fishing industry and that a suitable plan is put into action soon.


  • Information about Hector's dolphins from the Department of Conservation, Government of New Zealand (The article contains links to other government sources of information about the animal.)
  • The Hector's dolphin entry on the Red List of the IUCN
  • Maui dolphin information from the Department of Conservation
  • The Maui's dolphin entry on the IUCN’s Red List
  • Species directory entry for Cephalorhynchus hectori from NOAA (National Oceanic and Atmospheric Administration)

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2012 Linda Crampton


Linda Crampton (author) from British Columbia, Canada on August 02, 2014:

I agree, ologsinquito. I think that extinction is especially sad when it's the result of human action. Thanks for the visit.

ologsinquito from USA on August 02, 2014:

It's very good that efforts are being made to protect these magnificent creatures. No animal should become extinct. It isn't right.

Linda Crampton (author) from British Columbia, Canada on July 07, 2012:

Thank you for the visit, Bill. I appreciate your comment very much. Dolphins are certainly incredible animals. It's a great shame that some of them are in trouble.

Bill Holland from Olympia, WA on July 07, 2012:

Dolphins are such incredible creatures. It really saddens me, the loss of numbers due to nets. This is a wonderful hub that hopefully will bring awareness. Thank you!

Linda Crampton (author) from British Columbia, Canada on July 06, 2012:

Hi, PetMemorialWorld. It must be so enjoyable for you to see the dolphins and so sad for you that they are in trouble. Thanks for visiting and commenting.

Dean from New Zealand on July 06, 2012:

It is sad to see the demise of our dolphins, they really are a joy to experience.

Linda Crampton (author) from British Columbia, Canada on July 06, 2012:

Hi, CMHypno. What a wonderful trip to New Zealand that must have been! I agree, we do need to find effective ways to protect endangered animals such as Hector's and Maui's dolphins, and the solution to their population decline needs to be found quickly.

CMHypno from Other Side of the Sun on July 06, 2012:

I was lucky enough to see a pod of Hector's dolphins when I was on a whale watching tour at Kaikoura and they were enchanting to watch. I hope that they are protected and survive and we do urgently need to find a much better way of conserving our precious marine species

Linda Crampton (author) from British Columbia, Canada on July 06, 2012:

Hi, Wesman. Yes, it does seem that we need to have a completely different mindset about our role in the environment and about how we should lead our lives. Sadly, this doesn't look like it's going to happen anytime soon.

Wesman Todd Shaw from Kaufman, Texas on July 06, 2012:

I think the real solution to the world's problems to stop chasing the dollars, and grow your own garden.

Sounds awfully simplistic, but deciding to do one changes the mind's priority so it can finally be at ease, and the other would reduce so much industry as to slow the tide of awful we are doing to the planet.

Linda Crampton (author) from British Columbia, Canada on July 06, 2012:

I hope that an effective law is passed to protect the dolphins too, teaches. It's a sad situation, especially with respect to the Maui's dolphin. Thank you for the visit.

Linda Crampton (author) from British Columbia, Canada on July 06, 2012:

Hi, Chrissie. It is sad that there are so many animals on the edge of extinction, especially when this is due to the activity of humans. Thanks for the visit and the comment.

Dianna Mendez on July 06, 2012:

It is so sad that these beautiful creatures are endangered through man's carelessness. I hope that they pass the law to protect these animals.

chrissieklinger from Pennsylvania on July 06, 2012:

I loved all the videos this article had. Amazing that there are still so many animals that could become extinct in a few short years.

Linda Crampton (author) from British Columbia, Canada on July 05, 2012:

Thank you for the comment, Augustine. I agree, the dolphins are beautiful animals. I very much hope that they survive.

Augustine A Zavala from Texas on July 05, 2012:

I nver knew this species existed till now. Such beautiful specimens. I love learning about nature, especially the rare or endangered animals you write about in your hubs. Thank you for making me aware.

Linda Crampton (author) from British Columbia, Canada on July 05, 2012:

Hi, GoodLady. It is a worrying situation. I hope it's resolved in the best possible way, with the dolphin populations surviving and rebuilding and the fisherman finding alternate ways to catch fish. Thanks for the visit and the interesting comment.

Penelope Hart from Rome, Italy on July 05, 2012:

Lets hope they do get trawling fishing banned in their area. We built fish houses just off our coast here in the Maremma in Tuscany to prevent trawling. It upset the fishermen but in the long run, we will have some fish left!

Interesting and worrying Hub.

Linda Crampton (author) from British Columbia, Canada on July 05, 2012:

I would love to swim with bottlenose dolphins, drbj! It sounds like a wonderful experience. I'm sure that the setup was great for both humans and dolphins. I'm not sure about the advisability of swimming with Hector's dolphins, though (from the dolphins' point of view). It may not be a good idea to get dolphins that are endangered by human actions used to humans.

drbj and sherry from south Florida on July 05, 2012:

Thank you, Alicia, for this fascinating introduction to Hector's and Maui's dolphins. I hope the new Zealand government can be convinced of the importance of saving these intelligent mammals.

I have had the pleasure of swimming with bottlenose dolphins in the Caribbean and they are unique and wonderful, too. Much better swimmers than me though!

Linda Crampton (author) from British Columbia, Canada on July 05, 2012:

Thank you, Tom. I always appreciate your visits and kind comments! Thanks for the votes, too.

Thomas Silvia from Massachusetts on July 05, 2012:

Hi my friend, this is all great and interesting information about these dolphins . It will be very helpful to make everyone aware that they are close to becoming extinct and help to prevent that . Well done !

Vote up and more !!!

Linda Crampton (author) from British Columbia, Canada on July 05, 2012:

Hi, Nettlemere. I agree - these dolphins are a fabulous species! Thank you for the comment and the pin.

Nettlemere from Burnley, Lancashire, UK on July 05, 2012:

Very interesting and well researched. What a fabulous species, I loved the video of them swimming in the wild, could have just dived in their with them. Thank you for bringing their plight to my attention. Pinned

Linda Crampton (author) from British Columbia, Canada on July 04, 2012:

Thank you very much for the comment, clairemy. I appreciate your visit. Yes, I am very concerned about the fate of dolphins. They are fascinating animals with advanced brains, and it seems very wrong to me that an animal is endangered by human action when there is a way to avoid this.

Claire on July 04, 2012:

Great article, great information and obviously written by you because you really care. Voted up and up.

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