True's beaked whale (''Mesoplodon mirus'') is a medium-sized whale in the genus ''
Mesoplodon
Mesoplodont whales are 16 species of toothed whale in the genus ''Mesoplodon'', making it the largest genus in the cetacean order. Two species were described as recently as 1991 (pygmy beaked whale) and 2002 (Perrin's beaked whale), and marine b ...
''. It is native to the northern
Atlantic Ocean
The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...
. The common name is in reference to
Frederick W. True
Frederick William True (July 8, 1858 – June 25, 1914) was an American biologist, the first head curator of biology (1897–1911) at the United States National Museum, now part of the Smithsonian Institution.
Biography
He was born in Middletown ...
, a curator at the United States National Museum (now the Smithsonian).
Taxonomy
The species was first described in 1913 by Frederick W. True from an adult female that had stranded on the outer bank of Bird Island Shoal, Beaufort Harbor,
North Carolina
North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...
, in July 1912.
Previously, this species was thought to have two separate populations representing potential subspecies; one in the North Atlantic, and another in the southern
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...
. However, in 2021 the Indian Ocean population (which was found to have a significantly wider range throughout the
Southern Hemisphere) was described as a distinct species:
Ramari's beaked whale (''M. eueu'').
Physical description
This whale has a normal mesoplodont body, except that it is rotund in the middle and tapering towards the ends. The two distinctive teeth on the males are small and set on the very end of the beak (however additional teeth have been recorded ). The melon is rather bulbous, and leads into a short beak. There is a crease behind the blowhole, and a sharp dorsal ridge on the back near the dorsal fin. The coloration is gray to brownish gray on the back which is lighter below, and notably darker on the "lips", around the eye, and near the dorsal fin. There is sometimes a dark blaze between the head and dorsal fin as well. One female in the Southern Hemisphere was bluish black with a white area between the dorsal fin and tail as well as a light gray jaw and throat, as well as black speckling. One individual from the Canary Islands had an area of white from snout to blowhole. Scars from fighting and
cookiecutter shark
The cookiecutter shark (''Isistius brasiliensis''), also called the cigar shark, is a species of small squaliform shark in the family Dalatiidae. This shark lives in warm, oceanic waters worldwide, particularly near islands, and has been reco ...
s are present on males. This species reaches around with the females weighing and the males weighing . They are around long when born.
Behavior
They have been seen in small groups, and are believed to be squid eaters. The most complete description of recorded live sightings and strandings, as well as the first underwater footage, was published in a 2017 article by
Natacha Aguilar de Soto
Natacha Aguilar de Soto is a Spanish marine biologist at the University of La Laguna (ULL), Tenerife, Canary Islands. She is a Ramón y Cajal research and teaching fellow at ULL and has been a Marie Skłodowska-Curie Actions, Marie Skłodowska ...
in the open access journal
PeerJ
''PeerJ'' is an open access peer-reviewed scientific mega journal covering research in the biological and medical sciences. It officially launched in June 2012, started accepting submissions on December 3, 2012, and published its first articles ...
.
Population and distribution
This species lives in the North Atlantic and has stranded from
Nova Scotia
Nova Scotia is a Provinces and territories of Canada, province of Canada, located on its east coast. It is one of the three Maritime Canada, Maritime provinces and Population of Canada by province and territory, most populous province in Atlan ...
in the western Atlantic to
Ireland
Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...
in the eastern Atlantic and as far south as
Florida
Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...
, the
Bahamas
The Bahamas, officially the Commonwealth of The Bahamas, is an archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of its population. ...
, and
Canary Islands
The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...
. The species does not inhabit the Southern Atlantic and appears to avoid tropical waters.
Conservation
This species has not been hunted and has not been a victim of fishing nets. True's beaked whale is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (
ASCOBANS
Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, often abbreviated to ASCOBANS, is a regional agreement on the protection of small cetaceans that was concluded as the Agreement on the Con ...
) and the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (
ACCOBAMS
The Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic Area, or ACCOBAMS, is a regional international treaty that binds its States Parties on the conservation of Cetacea in their territories. ...
). The species is further included in the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (
Western African Aquatic Mammals MoU) and the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (
Pacific Cetaceans MoU).
Official webpage of the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region
/ref>
See also
*List of cetaceans
Cetacea is an infraorder that comprises the 94 species of whales, dolphins, and porpoises. It is divided into toothed whales (Odontoceti) and baleen whales (Mysticeti), which diverged from each other in the Eocene some 50 mya (unit), million years ...
References
Bibliography
*
*
Rare species found dead
*http://oceanfm.ie/news/2009/03/21/strandhill-whale-one-of-the-worlds-rarest-species/
Dead whale found on Buckroe Beach in Hampton (VA) (Nov. 9, 2009)
Beached whale first of its kind in New Zealand (Feb. 8, 2012)
True’s beaked whale (Mesoplodon mirus) in Macaronesia (Mar. 7, 2017)
External links
Factsheets
Whale & Dolphin Conservation Society (WDCS)
True's Beaked Whale - ARKive bio
*
{{Authority control
Mesoplodont whales
Cetaceans of Europe
Cetaceans of the Atlantic Ocean
Mammals described in 1913
Articles containing video clips