Marine Mammal Spotlight - Hector's Dolphins
Only found in New Zealand’s waters, this distinctive grey dolphin with black and white markings and a round dorsal fin (much like the shape of a Mickey Mouse ear) is the most easily recognised species of dolphin in New Zealand. The Hector’s dolphin is one of the smallest marine dolphins in the world.
Hector’s and Maui’s dolphins are known to Māori by other names, including tutumairekurai (special ocean dweller) & aihe.
Hector’s dolphin was named after James Hector who is believed to be the first person to have examined this species.
Two sub-species of Hector’s dolphins exist: the South Island Hector’s dolphin which is found around the South Island of New Zealand, and the Maui’s dolphin which is found off the west coast of the North Island.
Hector’s dolphins are found around the coast of the South Island but distribution is patchy. There is a population of Hector’s around Banks Peninsula area and also we have a small population in Kaikoura. We can see them at times on our tours in a small pod of between 2-3 individuals sometimes up to a dozen.
Hector’s dolphins are known to live to a maximum of about 20 years.
Like other dolphins, Hector’s use echolocation to find their food. They send out high frequency ‘clicks’ that bounce off surrounding objects and fish, giving the dolphins a detailed picture of their surroundings. This sonar is not used all the time, which may be one of the reasons why the dolphins get caught in nets.
Females reach sexual maturity between seven to nine years of age. They produce just one calf every two to three years, making population increase a very slow process.
Most females only have four or five calves in a lifetime. Calving usually occurs between November and mid-February, and calves stay with their mothers for up to two years.
Traditionally, Māori watched dolphin movements to predict the weather.
Threats to Hector’s dolphin
Dolphins and people have shared our shores and bays for centuries. In recent years, there has been a worldwide increase in awareness of marine mammals and a greater desire to protect them.
Set net fishing poses a major threat to Hector’s and Maui’s dolphins. Like all marine mammals they need to come to the surface regularly to breathe. If they become tangled in set nets, they will hold their breath until they suffocate.
Because these dolphins occur close inshore, often in bays and harbours, they are at risk of being injured by boats. Newborn dolphins are particularly vulnerable as they swim relatively slowly, close to the surface. Some have been killed by boat propellers, when unwary boaties have run them over.
Here are some tips on how you can help them
- Do not littler – rubbish can easily make its way to the sea where a dolphin may get tangled in it or mistakenly think it is food and eat it. Lids off plastic bottles can get stuck in their blowholes and slowly drown then.
- Make sure only water goes down storm water drains – keep pollutants out of the ocean!
- If you visit the beach and see some rubbish, please pick it up and put it in the bin so it doesn’t go in the sea.
- Be an ambassador / mouthpiece for these dolphins and tell others ways we can help keep their environment safe to live in.
QUICK FACTS ABOUT HECTOR’S DOLPHINS
- Hector’s dolphin is a marine mammal which means it breathes air, gives birth to live children, produces milk and is a warm-blooded animal.
- The scientific name for Hector’s dolphin is, “Cephalorhynchus hectori”.
- This marine mammal uses echolocation to search for food and navigate the ocean at night or when swimming in locations that have little to no light.
- These dolphins are a protected species and hunting them could lead to fines and/or jail time.
- Hector’s dolphin makes up one of around 80 known species of cetacea and one of around 40 known dolphin species.
- Aside from Maui’s dolphin this marine mammal is one of the smallest recorded species of cetacea. In fact, some researchers consider this to be the smallest cetacean while others consider Maui’s dolphin to be the smallest.
- Natural predators of Hector’s dolphin include sharks and killer whales.
- These marine mammals are known as conscious sleepers which means they are always aware of their need for oxygen and never fall completely asleep because they could drown if they don’t remain conscious.
- As a species dolphins are extremely intelligent and are able to perform acrobatic feats and complete complex tasks when properly trained. In fact dolphins are one of the most intelligent animals known to mankind aside from chimpanzees, apes and elephants.