Southern Right Whale Dolphin

## Description

The Southern right whale dolphin is a small and slender species of mammal, found in cool waters of the Southern Hemisphere. They can be easily distinguished from other cetacean species within their range as they are the only dolphins without dorsal fins in the Southern Hemisphere. They have streamlined and graceful bodies, a single blowhole, and a short and defined beak. A sharp dividing line separates the black dorsal part from the white ventral part of their body; it runs from the tail stock forward, dipping down to the flipper insertion and sweeping back up, below the eyes, to cross the melon between the blowhole and snout crease. Younger individuals can be grey/brownish dorsally but develop adult coloration within the first year. The flippers of Southern right whale dolphins are small, recurved, predominantly white and located about one-quarter of the way back from the snout tip.

## Distribution

Southern right whale dolphins have a circumpolar distribution across the Southern Hemisphere, generally occurring in cool temperate to Sub-Antarctic waters. They typically occur in offshore and deep waters, with temperatures ranging between 1 and 20 °C. In regions where deep waters approach the coast and in upwelling areas, they have occasionally been observed near shore.

## Behavior

Southern right whale dolphins are generally gregarious and may gather in pods of more than 1000 individuals although small groups of 1 to 10 have also been reported. They typically live in groups of 100-200 individuals but pods of just a few animals have also been observed, often associated with other cetacean species. Southern right whale dolphins are fast and energetic swimmers. Their movement is very graceful and they often move by leaping out of the water continuously. When they swim slowly, they expose only a small area of the head and back while surfacing to breathe. When traveling at higher speeds they may swim just below the surface, surfacing briefly to breathe and then submerge or swim rapidly at the surface, performing low-angle leaps covering much surface distance. While swimming these dolphins may perform breaching, belly-flopping, side-slapping, and lob-tailing (slapping the flukes on the water surface). Some groups will avoid boats, whereas others approach and possibly bow-ride. Southern right whale dolphins communicate with each other using clicks and whistles.

## Diet

Southern right whale dolphins are carnivores (piscivores). They prey on squid and a wide range of fish and may dive to depths in excess of 200 m (660 ft) in search of food.

## Reproduction

Little is known of this species’ reproductive biology. Newborn calves measure around 86 cm (34 in) in length and weigh around 5 kg (11 lb). Research suggests that males reach reproductive maturity at lengths between 212-220 cm (83-87 in) and females between 206-212 cm (81-83 in).

## Population

### Threats

Southern right whale dolphins were taken by whaling operations of the 19th century, primarily for their meat. In the past, they have been infrequently caught off the coasts of Peru and Chile, where their meat and blubber were used as food and crab bait. Large numbers of Southern right whale dolphins are sometimes taken by gillnetting and longline fishing in oceans off the southern coast of Australia. Off the west coast of southern Africa, there may be competition for forage resources with pelagic trawl fisheries due to the pelagic distribution of these dolphins and their squid based diet. The direct and indirect impacts of global climate change on the Southern right whale dolphin might have a cascading effect on the movement and feeding ecology. Seismic activity, for oil and gas, might also be a minor threat.

### Number

The IUCN Red List and other sources don’t provide the number of the Southern right whale dolphin total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.