Right whale dolphin

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Right whale dolphins
Northern right whale dolphin.jpg
Northern species, Lissodelphis borealis
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Delphinidae
Subfamily: Lissodelphininae
Genus: Lissodelphis
Gloger, 1841
Type species
Lissodelphis peronii
Species

L. borealis Peale, 1848
L. peronii Lacépède, 1804

Cetacea range map Right Whale Dolphin.png
Northern and southern right whale dolphin ranges

Right whale dolphins are cetaceans belonging to the genus Lissodelphis. It contains the northern right whale dolphin (Lissodelphis borealis) and the southern right whale dolphin (Lissodelphis peronii). These cetaceans are predominantly black, white beneath, and some of the few without a dorsal fin or ridge. They are smaller members of the delphinid family, oceanic dolphins, and very slender. Despite scientists being long acquainted with the species (the Northern species was identified by Titian Peale in 1848 and the Southern by Bernard Germain de la Cépède in 1804), little is known about them in terms of life history and behaviour.

Contents

Physical description

Size comparison with a human (northern species) Northern right whale dolphin size.svg
Size comparison with a human (northern species)

Both species have slender bodies, small, pointed flippers and a small fluke. Conspicuously, neither species has a dorsal fin; nor do right whales and this may explain the dolphins' name. The northern right whale dolphin is the only dolphin in the Pacific with this property. Similarly, the Southern is the only finless dolphin in the southern hemisphere. The two species can be readily distinguished (apart from the geographical separation in their ranges) by the extent of the whiteness on the body. Both have white bellies; however, the area of white coloration on the Southern species covers much more of the body — including the flanks, flippers, beak and forehead.

Northern males are about 220 cm (87 in) long at sexual maturity. Females are 200 cm (79 in). Both sexes become mature at about 10 years. New-born right whale dolphins are about half the length of their parents. The southern species is typically larger (up to 250 cm (98 in)) and heavier (up to 100 kg (220 lb) compared with the Northern's maximum of 80–90 kg (180–200 lb)). The dolphins live for about 40 years.

Distribution

The northern right whale dolphin is widely distributed in the temperate North Pacific in a band running from Kamchatka and mainland Japan in the west to British Columbia down to the Baja California Peninsula in the east. It is not known with certainty if they follow a migratory pattern. However, individuals have been observed close to the Californian shore following their main food source, squid, in winter and spring. Such sightings have not been recorded in summer. Otherwise these dolphins are pelagic. No global population estimates exist. There are an estimated 14,000 individuals close to the North American shoreline.

The southern right whale dolphin has a circumpolar distribution running from about 40° to 55°. They are sighted in the Tasman Sea in particular.

Behaviour

Right whale dolphins lack dorsal fins. Shown is the northern species, so the only white parts are the bellies, hidden from this angle. Anim1749 - Flickr - NOAA Photo Library.jpg
Right whale dolphins lack dorsal fins. Shown is the northern species, so the only white parts are the bellies, hidden from this angle.

Both species are highly gregarious. They move in pods of several hundred individuals and sometimes congregate in groups of 3000. [1] The groups may also contain dusky dolphins and pilot whales (in the south) and Pacific white-sided dolphins (in the north). These dolphins are some of the fastest swimmers (in excess of 40 km/h). They can by turns become very boisterous and breach and tail-slap or become very quiet and almost undetectable at sea. At high speed they can leap up to 7 metres across the ocean's surface in a graceful bouncing motion.

The species will generally avoid boats, but bow-riding has been recorded on occasion.

A single and rare stranding has been recorded for the northern species. On 9 June 2018, a 5.5-foot female was found deceased on Manzanita Beach on the coast of Oregon. There has been one recorded instance of 77 southern right whale dolphins stranding on Chatham Island.

Conservation

The southern species is under pressure from Peruvian whaling operations. The northern species has never been commercially targeted. However, tens of thousands of the northern species were killed in the 1980s due to their becoming caught in oceanic drift gillnets introduced at that time. Gillnets were banned by the United Nations in 1993. Conservation campaigners work vigorously to try to ensure these bans are retained.

Attempts to keep right whale dolphins in aquaria have all ended in failure and death. In all cases but one, they have died within three weeks.

Related Research Articles

Cetacea Whales, dolphins, and porpoises

Cetaceans are aquatic mammals constituting the infraorder Cetacea, including whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel themselves through the water with powerful up-and-down movement of their tail which ends in a paddle-like fluke, using their flipper-shaped forelimbs to maneuver.

Antarctic minke whale Species of mammal

The Antarctic minke whale or southern minke whale is a species of minke whale within the suborder of baleen whales. It is the second smallest rorqual after the common minke whale and the third smallest baleen whale. Although first scientifically described in the mid-19th century, it was not recognized as a distinct species until the 1990s. Once ignored by the whaling industry due to its small size and low oil yield, the Antarctic minke was able to avoid the fate of other baleen whales and maintained a large population into the 21st century, numbering in the hundreds of thousands. Surviving to become the most abundant baleen whale in the world, it is now one of the mainstays of the industry alongside its cosmopolitan counterpart the common minke. It is primarily restricted to the Southern Hemisphere and feeds mainly on euphausiids.

Rissos dolphin Species of marine mammal

Risso's dolphin is a dolphin, the only species of the genus Grampus. Some of the closest related species to these dolphins include: pilot whales, pygmy killer whales, melon-headed whales, and false killer whales.

White-beaked dolphin Species of mammal

The white-beaked dolphin is a marine mammal belonging to the family Delphinidae in the suborder Odontoceti.

Spectacled porpoise Species of mammal

The spectacled porpoise is a small to midsize porpoise indigenous to the Southern Ocean. It is one of the most poorly studied cetaceans, partly due to its remote range in the southern ocean. What little is known about this porpoise species has been gathered mainly from stranded individuals, and a few observations of living animals made at sea.

Hubbs beaked whale Species of mammal

Hubbs' beaked whale was initially thought to be an Andrews' beaked whale when discovered by ichthyologist Carl Hubbs; however, it was named in his honor when it was discovered to be a new species. This species has the typical dentition found in the genus, but its main outstanding features are a white "cap" on the head and very extensive scarring. The species is known from 31 strandings, a few at-sea sightings, and observations of two stranded whales that were kept in captivity for 16-25 days.

Trues beaked whale Species of mammal

True's beaked whale is a medium-sized whale in the genus Mesoplodon. It is native to the northern Atlantic Ocean. The common name is in reference to Frederick W. True, a curator at the United States National Museum.

Short-finned pilot whale Species of mammal

The short-finned pilot whale is one of the two species of cetaceans in the genus Globicephala, which it shares with the long-finned pilot whale. It is part of the oceanic dolphin family (Delphinidae).

Long-finned pilot whale Species of mammal

The long-finned pilot whale is a large species of oceanic dolphin. It shares the genus Globicephala with the short-finned pilot whale. Long-finned pilot whales are known as such because of their unusually long pectoral fins.

Sei whale Large species of baleen whale

The sei whale is a baleen whale, the third-largest rorqual after the blue whale and the fin whale. It inhabits most oceans and adjoining seas, and prefers deep offshore waters. It avoids polar and tropical waters and semi-enclosed bodies of water. The sei whale migrates annually from cool, subpolar waters in summer to temperate, subtropical waters in winter with a lifespan of 70 years.

Arnouxs beaked whale Species of whale

Arnoux's beaked whale, southern four-toothed whale, southern beaked whale, New Zealand beaked whale, southern giant bottlenose whale, or southern porpoise whale is one of the species of Berardius. Arnoux's and Baird's beaked whales are so similar that researchers have debated whether or not they are simply two populations of the same species, until genetic evidence and their wide geographical separation led them to be classified as separate. Little is known about their behavior because they only live in the ocean about 3,300 feet.

Shepherds beaked whale Species of mammal

Shepherd's beaked whale, also commonly called Tasman's beaked whale or simply the Tasman whale, is a cetacean of the family Ziphiidae. The whale has not been studied extensively. Only four confirmed at sea sightings have been made and 42 strandings recorded. It was first known to science in 1937, being named by W. R. B. Oliver after George Shepherd, curator of the Wanganui Museum, who collected the type specimen near Ohawe on the south Taranaki coast of New Zealand's North Island, in 1933.

False killer whale Species of oceanic dolphin in the genus Pseudorca but

The false killer whale is a species of oceanic dolphin that is the only extant representative of the genus Pseudorca. It is found in oceans worldwide but mainly frequents tropical regions. It was first described in 1846 as a species of porpoise based on a skull, which was revised when the first carcasses were observed in 1861. The name "false killer whale" comes from the similar skull characteristics to the killer whale.

Melon-headed whale Species of mammal

The melon-headed whale, also, less commonly, known as the electra dolphin, little killer whale, or many-toothed blackfish, is a small- to medium-sized toothed whale of the oceanic dolphin family (Delphinidae). The common name is derived from the head shape. Melon-headed whales are widely distributed throughout deep tropical/subtropical waters worldwide, however they are rarely encountered at sea. They are found near shore mostly around oceanic islands, such as Hawaii, French Polynesia, and the Philippines.

Northern right whale dolphin Species of mammal

The northern right whale dolphin is a small, slender and finless species of cetacean found in cold/temperate waters of the North Pacific Ocean. It is one of two species of right whale dolphins.

Southern right whale dolphin Species of mammal

The southern right whale dolphin is a small and slender species of cetacean, found in cool waters of the Southern Hemisphere. It is one of two species of right whale dolphin. This genus is characterized by the lack of a dorsal fin. The other species, the northern right whale dolphin, is found in deep oceans of the Northern Hemisphere and has a different pigmentation pattern than the southern right whale dolphin.

Hourglass dolphin Species of mammal

The hourglass dolphin is a small dolphin in the family Delphinidae that inhabits offshore Antarctic and sub-Antarctic waters. It is commonly seen from ships crossing the Drake Passage, but has a circumpolar distribution.

Striped dolphin Species of mammal

The striped dolphin is an extensively studied dolphin found in temperate and tropical waters of all the world's oceans. It is a member of the oceanic dolphin family, Delphinidae.

References

Notes

  1. Leatherwood, Stephen; Walker, William A (1979). "The northern right whale dolphin Lissodelphis borealis in the eastern North Pacific". In Winn, Howard Elliott; Olla, Bori L (eds.). Behavior of Marine Animals: Cetaceans. Vol. 3. Plenum Press. pp. 85–141. ISBN   9780306375736.

Other sources