This animal is one of the most infrequent and smallest marine dolphins. Hector's dolphin is named after Sir James Hector, a New Zealand scientist, who was the first to seriously explore the species. Sexes generally look alike, though males are usually shorter than females. Unlike other dolphins, this animal lacks a beak. The short and stocky body reminds a torpedo by its shape, narrowing towards the tail. The belly is white or cream, whereas the back and the sides are light grey. The dolphins exhibit a gray band, running across the middle of the body. They also have a black patch, stretching from the back of the snout around the eye to the flipper.
Hector’s dolphin is a New Zealand species, typically found around the major part of the South Island. Maui’s dolphin, a sub-species of Hector’s dolphin, has a very limited range, restricted to off the west coast of the North Island. The animal occurs in shallow seashore waters within 7 km off the coast (generally, less than half a mile off the shoreline) at depths of up to 100 meters. At certain times of year, when prey items change their location, the dolphin can be seen right at the seashore.
Hector's dolphins usually gather into small groups, consisting of 2 - 10 animals, which occasionally unite into larger temporary groups, found in close proximity to each other. Individuals normally associate with each other for less than a few days. These diurnal animals generally live in the same area, sometimes, throughout their lives. Hector's dolphins are known to be active and playful animals: bow-riding and playing with seaweed are common activities in this species. Hector's dolphins typically spend their time swimming along the coastline, coming to the surface to breathe, diving to forage as well as playing. They can frequently be observed leaping out of the water and landing on their side with a loud splash. In addition, sometimes they flex their body at the surface and can swim on their sides while feeding. In order to show aggression, these dolphins usually splash water with their tail, chase, bite or make bubble-blows.
Hector’s dolphins are carnivores (piscivores). They usually feeds in shallow waters with sandy bottom, consuming various species of fish such as flounder, red cod and mackerel, complementing its diet with crabs and squid.
Hector's dolphins have polygynandrous (promiscuous) mating system, where both males and females mate with multiple mates. During the courtship, the animals practice close contact, leaping chasing as well as belly displays. The breeding season occurs during the austral summer. Usually, a female yields a single baby every 2 - 4 years with the gestation period, lasting 10 - 12 months. The calves are typically born in the late spring and summer. The offspring stay with their mother for the first 1 - 2 years of their lives. During this period, the female does not breed. Females and their young are known to separate from non-breeding conspecifics, gathering into calf-cow groups. By the age of 2 years, the young are independent, often joining groups, consisting exclusively of young dolphins. Males of this species are sexually mature at 6 - 9 years old, whereas females reach maturity by 7 - 9 years of age.
Hector's dolphin is often caught in commercial and recreational fishiers across the area of its habitat, being entangled in gillnets, which pose a serious threat to this animal's population. Living in coastal areas, the animal suffers from a number of factors, including pollution, vessel traffic as well as modification of its natural range.
According to the IUCN Red List, the total population size of the Hector’s dolphin is about 7,000 mature individuals, including the North Island subspecies with population of 111 individuals. Overall, numbers of Hector’s dolphin population are decreasing today, and the species is currently classified as Endangered (EN) on the IUCN Red List.
Due to their diet, Hector's dolphins likely play an important role in controlling local fish populations.