Hector’s Dolphins, (or Cephalorhynchus Hectori , for those of you with an affinity for Latin) are the friendly creatures that grace the waters near New Zealand shores. Native to Aotearoa, and commonly found along the coast of Banks Peninsula, these dolphins have sparked excitement in local scientists for the past 30 or so years, and now we know more about them than ever. Here are ten things about Hector’s Dolphins you may not have known:
10. Under the Radar
The way Hector’s Dolphins communicate is often inaudible to the human ear. Except for the occasional squeal or cry, their sounds just don’t register to us. They communicate through short, high frequency clicks which last about 1/7000th of a second and are usually at about 120 kHz – 6 times higher than the human ear can hear. These are emitted as pulses in the water, and they become more frequent when they get closer to a target.
9. Lone Wolves Making Packs
From research, it seems that although Hector’s Dolphins are inclined to stick together in groups, they don’t really have strong family ties or set packs that they are always associated with. Although mothers stick with their children to show them the ropes as they grow up, and the occasional dolphin has a ‘best friend’ or two, relationships between males and females are far from monogamous and researchers usually find that the same dolphins are not often seen together.
We now know that Hector’s Dolphins on average live into their early twenties. How? Their teeth. When they are born, they start out with hollow cone-like teeth and every year, two more layers will grow up into them to fill out the cone – one in summer, and one in winter. Scientists count the layers, like rings on a tree, to find the age of a dolphin.
7. Massive brains
Hector’s Dolphins have one of the largest brain-to-body weight ratios in the animal kingdom, and the largest amongst dolphins. With 1.7% of their body weight residing in their brain, it’s really no wonder they have a reputation for being intelligent. The average human ratio is 1.9%, which doesn’t seem to be particularly far ahead. And not only are they catching up to us in size, but in the way we value our smarts too; the areas of the dolphin brain associated with reason and creativity are surprisingly well developed.
6. Dolphins just play for fun
Unlike many creatures in the animal kingdom that learn to fight or hunt through play amongst their group, Hector’s Dolphins just play for the fun of it. They’re really friendly around humans, and you’ll often see them surfing in the wake of a passing boat, or tossing around a twig, some seaweed, or leaves near the surface of the water. When they’re enjoying themselves, they blow bubbles under the water to show their excitement. Many scientists believe that the fact that they seem to play just for the pleasure of it is a sign of their intelligence.
5. Punks and Sharkbait
Since New Zealand scientists started studying Hector’s Dolphins in the ‘80s, they’ve gotten to know quite a few characters. Identifying features and repeat visits mean that they’re quite familiar with dolphins like Biggus Nickus, whose name was inspired by the nick in his dorsal fin (and the Monty Python film, Life of Brian). Others include Punk, who had a calf every two years from 2000-2008, and Sharkbait, who researchers met when he had a fresh wound on his back from an attack.
4. No Tagging
In 2004, the Department of Conservation tagged three Hector’s Dolphins in the Banks Peninsula area. This was met with much outrage from scientists, conservationalists, and dolphin enthusiasts alike. As Hector’s Dolphins are so friendly and so willing to come up to researchers time and time again, key scientists, Professors Slooten and Dawson want to keep them free from tags. They believe that it is unethical to tag animals if it means putting them through stress for research that can be done through other means. Tagging can also change the behaviour of an animal due to human intervention, which would skew observational findings. And of course, scientists have the ability to monitor the dolphins through the photographic records they keep, so they can learn about Hector’s Dolphins without causing them unnecessary harm. Therefore the scientists like to keep a tag-free policy when it comes to Hector’s Dolphins.
3. A Different Dorsal
It’s easy to tell the difference between your standard dolphins from other waters and New Zealand’s own Hector’s Dolphin. Aside from the fact that Hector’s Dolphins are predominantly grey and quite small in comparison to their international counterparts, they have a very rounded dorsal fin. Other species you may spot in New Zealand waters that aren’t natives will have a sickle or triangular shaped fin, meaning it’s pretty easy for a Hector’s Dolphin to stand out from the crowd. In fact, they are sometimes known as the ‘Mickey Mouse Dolphin’ – it’s easy to see why.
2. Hungry Dolphins
Being warm-blooded creatures in a very cool environment, it’s important that dolphins eat as much as they can to keep their energy levels up with the activity they do. A typical male Hector’s Dolphin will eat about 11% of his body weight in fish each day as long as he can get hold of it. That’s the equivalent of an average adult male eating 37 Big Macs in one day!
1. Hector’s Dolphins are tiny
Relative to the size of other sea dwelling mammals, the native New Zealand dolphin is quite small. Going by length, Hector’s Dolphins are the smallest in the world – the average Hector’s Dolphin is the size of a five year old child, whereas the average Bottlenose is the length of a small family car! However, there’s a little competition for the title, because by weight, the Franciscana dolphin of South America is ten kilograms lighter than a fully grown Hector’s Dolphin.