Hector's and Maui's Dolphins: Vulnerable and Endangered Animals

Updated on October 3, 2019
AliciaC profile image

Linda Crampton is a writer and teacher with an honors degree in biology. She loves to study nature and write about living things.

A close-up view of a Hector's dolphin
A close-up view of a Hector's dolphin | Source

Unique Dolphins in New Zealand

The Hector’s dolphin and the Maui’s dolphin are found only off the coast of New Zealand. The latest population assessment of Hector’s dolphins estimates that around 15,000 individuals exist. They are classified as "nationally vulnerable". The critically endangered population of Maui’s dolphins likely consists of around 63 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, whose population requires an emergency intervention.

The animals are close relatives. They are relatively small members of the order Cetacea, which includes whales, dolphins, and porpoises. They look quite similar and are light grey animals with black and white markings. The dolphins 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

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 dolphins that are seen in this location are sometimes referred to as Maui or Māui dolphins or as North Island ones.

Another view of a Hector's dolphin
Another view of a Hector's dolphin | Source

Identification of the Hector's Dolphin

The Hector's dolphin is named after Sir James Hector. 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. Their 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. Their lower surface is white. A white stripe extends 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.

Hector's Dolphins Swimming Underwater

Daily Life

Hector's dolphins live mostly in shallow water less than 100 meters deep and are found close to the shore. New 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 animals. 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.

Like other cetaceans, both Hector's and Maui's dolphins find their prey by echolocation. During this process, a dolphin emits very high frequency sounds, also known as ultrasonic sounds. The sound waves bounce off solid objects and return to the dolphin, 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 dolphins like to swim close to boats. Some Hector's dolphins will swim next to humans in the water.

Two Maui's dolphins
Two Maui's dolphins | Source

Reproduction

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 will 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.

An Encounter With Maui's 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 dolphins 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.

A Department of Conservation Video of the Animals

Estimates of Population Size

The population of Hector's dolphins is currently estimated to be around 15,000 individuals. The Maui's dolphin population is estimated to be approximately 63 animals over the age of one. The number of calves is unknown. Different sources give different values for the numbers. The estimated numbers of the Maui's dolphin are so small that the loss of even one animal would be a serious event for the subspecies.

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 and the situation doesn't seem to be quite so serious today.

Though the dolphin's status is better than it was and its population has appeared to stabilize, the animals still need some help, as the zoologists in the video below mention. (The video was posted on the last day of 2018.) Some otherwise useful sources of information, including the maker of the video, still refer to the IUCN's earlier assessment of the animal's status as "endangered". The IUCN is a respected organization. I wish it would update the dolphin's status and if necessary say why it disagrees with other assessments.

There is no disagreement about the plight of the Maui's dolphin. The animal's population is classified as critically endangered by all of the sources that I've seen. "Critically" endangered means that the animals are in serious danger of extinction. I find the situation a little concerning beyond the critically endangered status, though. The estimated population size of the animal has stayed the same for many years, which makes me wonder how accurate it is.

Zoologists Discuss the Hector's Dolphin

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

— New Zealand Department of Conservation (with respect to the Hector's dolphin)

Population Threats

The biggest threat to both dolphins is fishing by set (gill) nets and trawling nets. The dolphins seem to have difficulty detecting gill nets, which generally have a fine mesh. The mammals may be able to detect nets with a coarser mesh 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.

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

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.

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.

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 has a vulnerable status.

Conservation

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 regulations. The debates and disagreements are taking up valuable time that is needed to prevent the extinction of the Maui's dolphins and allow its population to increase.

One of the zoologists in the video above is happy that a protection zone has been established for the Hector's dolphin, allowing its population to stabilize. They also says that if the protection zone was extended, the population would likely increase and be safer. I think that protecting both of the subspecies of Cephalorhynchus hectori is important.

References

Questions & Answers

    © 2012 Linda Crampton

    Comments

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      • AliciaC profile imageAUTHOR

        Linda Crampton 

        5 years ago from British Columbia, Canada

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

      • ologsinquito profile image

        ologsinquito 

        5 years ago from USA

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

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

        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.

      • billybuc profile image

        Bill Holland 

        7 years ago from Olympia, WA

        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!

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

        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.

      • PetMemorialWorld profile image

        Dean 

        7 years ago from New Zealand

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

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

        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 profile image

        CMHypno 

        7 years ago from Other Side of the Sun

        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

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

        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 profile image

        Wesman Todd Shaw 

        7 years ago from Kaufman, Texas

        I think the real solution to the world's problems ...is 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.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

        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.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

        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.

      • teaches12345 profile image

        Dianna Mendez 

        7 years ago

        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 profile image

        chrissieklinger 

        7 years ago from Pennsylvania

        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.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

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

      • A.A. Zavala profile image

        Augustine A Zavala 

        7 years ago from Texas

        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.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

        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.

      • GoodLady profile image

        Penelope Hart 

        7 years ago from Rome, Italy

        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.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

        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 profile image

        drbj and sherry 

        7 years ago from south Florida

        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!

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

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

      • kashmir56 profile image

        Thomas Silvia 

        7 years ago from Massachusetts

        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 !!!

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

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

      • Nettlemere profile image

        Nettlemere 

        7 years ago from Burnley, Lancashire, UK

        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

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 years ago from British Columbia, Canada

        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.

      • clairemy profile image

        Claire 

        7 years ago

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

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