Northern Right Whale Dolphin
Encyclopedia
The Northern right whale dolphin (Lissodelphis borealis) is a small and slender species of marine mammal found in the North Pacific Ocean
. The Northern right whale dolphin travels in groups of up to 2000, often with other cetaceans, in deep waters of the North Pacific. The dolphin is one of two species of Right whale dolphin
, the other being found in cooler oceans of the southern hemisphere.
The species has a streamlined body with a sloping forehead, are more slender than other delphinids, and lack any fin or ridge on their smoothly curving backs. The beak is short and well defined, a straight mouthline, and an irregular white patch on chin. The flippers are small, curved, narrow and pointed, the body is mostly black while the underside is partly white or lighter in colour. The tail flukes are triangular and, like the flippers, pointed. Adults weigh between 60–100 kg. They have 74 to 108 thin and sharp teeth, not externally visible. As young calves, these dolphins are greyish brown or sometimes cream. They stay like this for a year, before their body turns mainly black, with a clear white belly, and a white streak to their lower jaw.
Adults range in size from 2 metres in length, females are recorded as 2.3–2.6 m, males at 3.1 m, the sexes are otherwise similar in colour and appearance. Newborns are around 90 centimetres. Northern Right Whale Dolphins have less white on their bodies than the Southern species.
Northern right whale dolphin are found as individuals, or in groups as large as 2000. The group's average number is 110 in the eastern North Pacific and 200 individuals in the western North Pacific. They often associate with Pacific white-sided dolphin
s.
They can reach speeds of up to 30–40 kilometres per hour across the open ocean, never along shallow coasts. They can dive up to 200 metres in search of fish, especially lanternfish
, and squid. They are found in temperate to cold waters, 24 to 8 degrees Celsius, from latitudes 51°N to 31°N between the west coast of North America and Asia.
Targeting of this species by the whaling
industry for food is recorded in the eighteenth century. Records from the late twentieth century show large numbers of Lissodelphis borealis were caught in drift nets, used for large scale squid fishing, which is estimated to have reduced the population by one to three quarters. The current population trend is unknown, IUCN Redlist gives the conservation status as Least Concern
.
The species was first described by Titian Peale
in 1848. The genus Lissodelphis is placed within Delphinidae, the oceanic dolphin family of cetaceans. The epithet of the genus was derived from Greek lisso, smooth, and delphis; the specific epithet, borealis, indicates the northern distribution. The common name
s for the species formerly included Northern right whale porpoise, Snake porpoise, and Pacific right whale porpoise. Both species in the genus are also referred by the name Right whale dolphin
, a name derived from the Right whales Eubalaena, which also lack a dorsal fin.
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. The Northern right whale dolphin travels in groups of up to 2000, often with other cetaceans, in deep waters of the North Pacific. The dolphin is one of two species of Right whale dolphin
Right whale dolphin
Right whale dolphins are cetaceans belonging to the genus Lissodelphis. It contains the Northern Right Whale Dolphin and the Southern Right Whale Dolphin . These cetaceans are predominantly black, white beneath, and one of the few without a dorsal fin or ridge...
, the other being found in cooler oceans of the southern hemisphere.
The species has a streamlined body with a sloping forehead, are more slender than other delphinids, and lack any fin or ridge on their smoothly curving backs. The beak is short and well defined, a straight mouthline, and an irregular white patch on chin. The flippers are small, curved, narrow and pointed, the body is mostly black while the underside is partly white or lighter in colour. The tail flukes are triangular and, like the flippers, pointed. Adults weigh between 60–100 kg. They have 74 to 108 thin and sharp teeth, not externally visible. As young calves, these dolphins are greyish brown or sometimes cream. They stay like this for a year, before their body turns mainly black, with a clear white belly, and a white streak to their lower jaw.
Adults range in size from 2 metres in length, females are recorded as 2.3–2.6 m, males at 3.1 m, the sexes are otherwise similar in colour and appearance. Newborns are around 90 centimetres. Northern Right Whale Dolphins have less white on their bodies than the Southern species.
Northern right whale dolphin are found as individuals, or in groups as large as 2000. The group's average number is 110 in the eastern North Pacific and 200 individuals in the western North Pacific. They often associate with Pacific white-sided dolphin
Pacific White-sided Dolphin
The Pacific White-sided Dolphin is a very active dolphin found in the cool to temperate waters of the North Pacific Ocean.-Taxonomy:...
s.
They can reach speeds of up to 30–40 kilometres per hour across the open ocean, never along shallow coasts. They can dive up to 200 metres in search of fish, especially lanternfish
Lanternfish
Cooper Lanternfishes are small mesopelagic fish of the large family Myctophidae. One of two families in the order Myctophiformes, the Myctophidae are represented by 246 species in 33 genera, and are found in oceans worldwide. They are aptly named after their conspicuous use of bioluminescence...
, and squid. They are found in temperate to cold waters, 24 to 8 degrees Celsius, from latitudes 51°N to 31°N between the west coast of North America and Asia.
Targeting of this species by the whaling
Whaling
Whaling is the hunting of whales mainly for meat and oil. Its earliest forms date to at least 3000 BC. Various coastal communities have long histories of sustenance whaling and harvesting beached whales...
industry for food is recorded in the eighteenth century. Records from the late twentieth century show large numbers of Lissodelphis borealis were caught in drift nets, used for large scale squid fishing, which is estimated to have reduced the population by one to three quarters. The current population trend is unknown, IUCN Redlist gives the conservation status as Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
.
The species was first described by Titian Peale
Titian Peale
Titian Ramsay Peale was a noted American artist, naturalist, entomologist and photographer. He was the sixteenth child and youngest son of noted American naturalist Charles Willson Peale.-Biography:...
in 1848. The genus Lissodelphis is placed within Delphinidae, the oceanic dolphin family of cetaceans. The epithet of the genus was derived from Greek lisso, smooth, and delphis; the specific epithet, borealis, indicates the northern distribution. The common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
s for the species formerly included Northern right whale porpoise, Snake porpoise, and Pacific right whale porpoise. Both species in the genus are also referred by the name Right whale dolphin
Right whale dolphin
Right whale dolphins are cetaceans belonging to the genus Lissodelphis. It contains the Northern Right Whale Dolphin and the Southern Right Whale Dolphin . These cetaceans are predominantly black, white beneath, and one of the few without a dorsal fin or ridge...
, a name derived from the Right whales Eubalaena, which also lack a dorsal fin.