Arnoux's beaked whale

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Arnoux's beaked whale
Temporal range: Middle Miocene to present, 11.5–0  Ma
Berardius arnuxii 2.jpg
Arnoux's beaked whale size.svg
Size compared to an average human
CITES Appendix I (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Ziphiidae
Genus: Berardius
Species:
B. arnuxii
Binomial name
Berardius arnuxii
Duvernoy, 1851
Cetacea range map Arnoux 27s Beaked Whale.png
Arnoux's beaked whale range

Arnoux's beaked whale (Berardius arnuxii), also called the southern four-toothed whale, southern beaked whale, New Zealand beaked whale, southern giant bottlenose whale and southern porpoise whale is one of the species of Berardius . [3] Arnoux's and Baird's beaked whales are so similar that researchers 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 due to infrequent encounters with live individuals. [4]

Contents

Etymology

Named Berardius arnuxii in 1851 for the French surgeon, M. Arnoux, who presented the skull to the Paris Museum of Natural History in 1846. [5]

Physical description

Skeleton of Berardius arnuxii, showing a skull adapted to vocalizations Berardius arnuxii skeleton.JPG
Skeleton of Berardius arnuxii, showing a skull adapted to vocalizations

Arnoux's and Baird's beaked whales, have very similar features and would be indistinguishable at sea if they did not exist in disjoint locations. [6] Both whales reach similar sizes, have bulbous melons, and long prominent beaks. Their lower jaw is longer than the upper, and once sexual maturity is reached the front teeth are visible even when the mouth is fully closed. [6] [7] The Baird's and Arnoux's beaked whales are the only whales in the Ziphiidae family where both sexes have erupted teeth. The teeth in the Ziphiidae are presumed to be used by males for fighting and competition for females. Ziphiidae have the most prevalent and pronounced markings caused by teeth scarring among the cetaceans.[ citation needed ] Front-facing teeth may be covered in barnacles after many years. [7]

Baird's and Arnoux's beaked whales have similarly shaped small flippers with rounded tips, and small dorsal fins that sit far back on their bodies. [7] Adult males and females of both species pick up numerous white linear scars all over the body as they age, and these may be a rough indicator of age. These traits are similar in both sexes, as there is little sexual dimorphism in either species. [6] [7] Among the observed differences in the sexes is their size: female Baird's and Arnoux giant beaked whales are slightly larger than the males.

Population and distribution

Arnoux's beaked whale breaching in Antarctica. Arnoux's beaked whale in Antarctica.jpg
Arnoux's beaked whale breaching in Antarctica.

Arnoux's beaked whales inhabit great tracts of the Southern Ocean. Large groups of animals, pods of up to 47 individuals, have been observed off Kemp Land, Antarctica. [8] Beachings in New Zealand and Argentina indicate the whale may be relatively common in the Southern Ocean between those countries and Antarctica; sporadic sightings have been recorded in polar waters, such as in McMurdo Sound. [9] It has also been spotted close to South Georgia and South Africa, indicating a likely circumpolar distribution. The northernmost stranding was at 34 degrees south, indicating the whales inhabit cool and temperate, as well as polar, waters. There is no stock report for the Arnoux's beaked whale to date by NOAA.

An April 2022 sighting in the Weddell Sea prompted a review of 108 prior sightings of 1125 individuals, dating to 1986-1998. This review corroborated their presumed range in the Southern Ocean, and found that Arnoux's beaked whales prefer the coasts of icy landmasses. In temperate regions above 60 degrees South, they can also be found near continents, even in fjords far inland. [10]

Conservation

Arnoux's beaked whale has rarely been exploited, and although no abundance estimates are available, the population is not believed to be endangered. Arnoux's beaked whale is covered by the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU). [11]

Related Research Articles

<span class="mw-page-title-main">Beaked whale</span> Family of mammals

Beaked whales are a family of cetaceans noted as being one of the least-known groups of mammals because of their deep-sea habitat, reclusive behavior and apparent low abundance. Only three or four of the 24 existing species are reasonably well-known. Baird's beaked whales and Cuvier's beaked whales were subject to commercial exploitation, off the coast of Japan, while the northern bottlenose whale was extensively hunted in the northern part of the North Atlantic in the late 19th and early 20th centuries.

<span class="mw-page-title-main">Hubbs' beaked whale</span> 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.

<span class="mw-page-title-main">Ginkgo-toothed beaked whale</span> Species of mammal

The ginkgo-toothed beaked whale is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth. It is a fairly typical-looking species, but is notable for the males not having any scarring.

<span class="mw-page-title-main">Hector's beaked whale</span> Species of mammal

Hector's beaked whale, is a small mesoplodont living in the Southern Hemisphere. This whale is named after Sir James Hector, a founder of the colonial museum in Wellington, New Zealand. The species has rarely been seen in the wild.

<span class="mw-page-title-main">Strap-toothed whale</span> Species of whale

The strap-toothed beaked whale, also known as Layard's beaked whale, is one of the largest members of the Mesoplodon genus, growing to 6.2 m (20 ft) in length and reaching up to 1,300 kg (2,900 lb). The common and scientific name was given in honor of Edgar Leopold Layard, the curator of the South African Museum, who prepared drawings of a skull and sent them to the British taxonomist John Edward Gray, who described the species in 1865.

<span class="mw-page-title-main">True's beaked whale</span> 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.

<span class="mw-page-title-main">Tropical bottlenose whale</span> Species of mammal

The tropical bottlenose whale, also known as the Indo-Pacific beaked whale or Longman's beaked whale, was considered to be the world's rarest cetacean until recently, but the spade-toothed whale now holds that position. As of 2010, the species is now known from nearly a dozen strandings and over 65 sightings. This is the only species in the genus Indopacetus.

<span class="mw-page-title-main">Cuvier's beaked whale</span> Species of whale

Cuvier's beaked whale, goose-beaked whale, or ziphius is the most widely distributed of all beaked whales in the family Ziphiidae. It is smaller in size than most baleen whales—and indeed the larger toothed cetaceans —yet it is large among the beaked whales and smaller cetaceans, appearing somewhat like a bigger and stockier bottlenose dolphin. Cuvier's beaked whale is pelagic, generally inhabiting waters deeper than 300 m (1,000 ft), though it has been observed closer to shore on occasion. In these offshore waters, Cuvier's beaked whale executes some of the deepest, longest recorded dives among whales, and extant mammals, at 2,992 m (9,816 ft), for 222 minutes. While likely diving to forage and hunt prey, such as cephalopods, and potentially evade predators, the frequency and exact reason for these extraordinary dives is unclear. Despite its deepwater habitat, it is one of the most frequently-spotted beaked whales when surfacing.

<i>Berardius</i> Genus of mammals

The four-toothed whales or giant beaked whales are beaked whales in the genus Berardius. They include Arnoux's beaked whale in cold Southern Hemispheric waters, and Baird's beaked whale in the cold temperate waters of the North Pacific. A third species, Sato's beaked whale, was distinguished from B. bairdii in the 2010s.

<span class="mw-page-title-main">Baird's beaked whale</span> Species of mammals

Baird's beaked whale, also known as the northern giant bottlenose whale, North Pacific bottlenose whale, giant four-toothed whale, northern four-toothed whale and the North Pacific four-toothed whale, is a species of whale from the genus Berardius. Baird's and Arnoux's beaked whales are so similar that researchers have debated whether or not they are simply two populations of the same species. However, genetic evidence and their wide geographical separation has led them to be classified as separate. Baird's beaked whale is the second largest living species of toothed whale after the sperm whale.

<span class="mw-page-title-main">Shepherd's beaked whale</span> 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 and the only species in the genus Tasmacetus. 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.

<span class="mw-page-title-main">Hourglass dolphin</span> 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.

<span class="mw-page-title-main">Perrin's beaked whale</span> Species of mammal

Perrin's beaked whale is part of the toothed whale suborder and is one of over 90 known cetaceans in existence today. Beaked whales are part of the family Ziphiidae, which are the second most diverse group out of all marine mammals with over 20 species currently recognized. Although diverse, little is understood about these timid, deep divers that can dive for up to two hours. The whales are partially named after their beak shaped jaw, which extends from their small head. The genus name Mesoplodon comes from the Greek meanings of meso- (middle), - hopla (arms), - odon (teeth), and may be translated as 'armed with a tooth in the center of the jaw'.

<span class="mw-page-title-main">Spade-toothed whale</span> Species of beaked whale

The spade-toothed whale is the rarest species of beaked whale. Most specimens found have been in the South Pacific, mostly in New Zealand, but they have also been found in Chile. It is a species of which there is very little known.

<span class="mw-page-title-main">Southern bottlenose whale</span> Species of mammal

The southern bottlenose whale is a species of whale, in the Ziphiid family, one of two members of the genus Hyperoodon. Seldom observed, the southern bottlenose whale is resident in Antarctic waters. The species was first described by English zoologist William Henry Flower in 1882, based on a water-worn skull from Lewis Island, in the Dampier Archipelago, Western Australia. They live in deep ocean waters over 1000 meters.

References

  1. Brownell Jr., R.L. & Taylor, B.L. (2021) [amended version of 2020 assessment]. "Berardius arnuxii". IUCN Red List of Threatened Species . 2021: e.T2762A197190014. doi: 10.2305/IUCN.UK.2021-1.RLTS.T2762A197190014.en . Retrieved 4 December 2023.
  2. "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. Handbook of marine mammals. Vol. 4. Sam H. Ridgway, Richard J. Harrison. London: Academic Press. 1981–1999. ISBN   0-12-588501-6. OCLC   7819810.{{cite book}}: CS1 maint: others (link)
  4. "Arnoux's Beaked Whale – A Complete Guide to Whales, Dolphins and Porpoises".
  5. Australian Museum, Arnoux's Beaked Whale
  6. 1 2 3 "Arnoux's beaked whale". Archived from the original on 4 February 2016. Retrieved 12 January 2016.
  7. 1 2 3 4 "Baird's beaked whale". WDC, Whale and Dolphin Conservation. Archived from the original on 17 July 2018. Retrieved 2018-06-07.
  8. Rogers, Tracey L.; Brown, Sarah M. (1970). "Acoustic observations of Arnoux's beaked whale (Berardius arnuxii) off Kemp Land, Antarctica". Marine Mammal Science. 15: 192–198. doi:10.1111/j.1748-7692.1999.tb00789.x.
  9. "Mystery Whales Put on Show at Scott Base | EveningReport.nz". Archived from the original on 11 March 2016. Retrieved 11 March 2016.
  10. Feij, Bram; Kühn, Susanne; Meijboom, André; van Franeker, Jan A.; Bornemann, Horst; Kelly, Nat; Schaafsma, Fokje L. (2024-07-13). "Distribution of Arnoux's beaked whales ( Berardius arnuxii )". Marine Mammal Science. doi:10.1111/mms.13158. ISSN   0824-0469.
  11. "CMS Pacific Cetaceans MOU for Cetaceans and their Habitats in the Pacific Islands Region". Archived from the original on 16 March 2016. Retrieved 10 April 2012.