Hector's Dolphin

## About

A pair of Hector's dolphins.

Hector's dolphin ***(Cephalorhynchus hectori)*** is the smallest dolphin in the Delphinidae family, and one of the only mammals native to New Zealand. Hector's dolphin are extremely identifiable and uniquely small when compared to other dolphins, having silver dorsums and sides with black and white accented heads, fins and sides. Hector's dolphins were named after Sir James Hector (1834-1907), who examined the first dolphin specimen, and was one of the most influential scientists in New Zealand at the time. Hector's dolphins are often confused with Māui's dolphins ***(Cephalorhynchus hectori maui)*** for their similar range and appearance however, Hector's are slightly smaller being 1.2m (4ft) in length and weighing 40-60kg (88-132lbs). This makes the Hector's dolphin the smallest dolphin species on Earth.

## Diet

Hector's dolphins are opportunistic predators that eat mainly fish. They will deliberately target larger individuals of the fish species they hunt and will even stick close to the coastal breeding grounds of these fish during mating season, in order to acquire larger food sources. Hector's dolphins are also known to eat small squid species.

## Conservation Status

Hector's dolphins are recognised to be endangered by the IUCN. Hector's dolphins are majorly threatened by the increasing use of gillnets in the area in which it lives. These gillnets often tangle up the dolphins, trapping them which leads to eventual drowning. These nets are not visible to dolphins making it incredibly hard for them to evade them, causing them to swim directly into them and getting entangled. Hector's dolphins are further threatened by the increasing costal industrialisations which are occurring on New Zealand's maritime fronts. Hector's dolphins also often come into contact with humans and are known to collide with boats like fishing vessels. This increased boat to dolphin interaction is due to the coastal development in New Zealand.

## Range and Population

Hector's dolphins are present in sparse numbers on both north and south Islands of New Zealand. The population of the Hector's dolphin is decreasing due to the factors described above and they now have a population of 7,000-7,381 individuals. The range of the Hector's dolphin overlaps with the Māui's dolphin's range in the coastal regions of the Western North Island. Hector's dolphins prefer to live in coastal regions and shallow waters. The exact depth at which the Hector's dolphin lives in varies but is usually 100m (328ft), around 15km (9.3mi) off shore. Hector's dolphins are more likely to stay situated closer to the coast in Summer months (corresponding with the mating and spawning season of their prey fish), and during Winter they typically disperse into further open waters. Some individual Hector's dolphins can be found in drastically varying locations year round, with one individual being photographed twice in two areas that are separated by 106km (65.8mi).

## Behaviour

Hector's dolphins are extremely expressive Cetaceans, conveying a wide variety of emotion through movements and posture. Hector's dolphins will breach sporadically and often when they are excited, they will also flap their caudal (tail) fins when happy however, this can also be a sign of irritation. The most identifiable movement the Hector's dolphins is known to do is splashing and blowing bubbles, which is an obvious sign of aggression. Hector's dolphins travel in pods with members ranging from 2-10 individuals, and both genders are allowed by their pods to join other pods. Amon the large pods there are also smaller 'mini pods' which mostly consist of pairs. Hector's dolphins are also relatively slow swimming dolphins, making them susceptible to predation by shark species in the area.

### Relationship with Humans

Hector's dolphins are generally pretty skittish towards humans and similarly to other dolphin species exposed to human industrialisation, they will usually avoid motorised vessels or humans if able. Hector's dolphins are much more secluded and shy when compared to other marine Delphinids, which is part of the reason why it is so hard to research these mysterious dolphins.

## In Captivity

There are no Hector's dolphins in any form of marine institute or zoo. This is mostly because the captive keeping of Cetaceans is generally frown upon by the general public as well as many animal welfare associations.

## Sources

* IUCN Red List of Threatened Species - https://www.iucnredlist.org/species/4162/44199757
* Hector's Dolphin | WWF - https://www.worldwildlife.org/species/hector-s-dolphin
* Hector's Dolphin | DOLPHINS-WORLD - https://www.dolphins-world.com/hectors-dolphin/