Pygmy right whale
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The pygmy right whale (''Caperea marginata'') is a species of
baleen whale Baleen whales (systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea (whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their ...
. It may be a member of the cetotheres, a family of baleen whales which until 2012 were thought to be
extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
; ''C. marginata'' has otherwise been considered the
monotypic taxon In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...
sole member of the
family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Neobalaenidae and is the only member of the genus ''Caperea''. First described by
John Edward Gray John Edward Gray, FRS (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used for ...
in 1846, it is the smallest of the
baleen whales Baleen whales (systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea (whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their ...
, ranging between in length and in mass. Despite its name, the pygmy right whale may have more in common with the
gray whale The gray whale (''Eschrichtius robustus''), also known as the grey whale,Britannica Micro.: v. IV, p. 693. gray back whale, Pacific gray whale, Korean gray whale, or California gray whale, is a baleen whale that migrates between feeding and bree ...
and
rorqual Rorquals () are the largest group of baleen whales, which comprise the family Balaenopteridae, containing ten extant species in three genera. They include the largest animal that has ever lived, the blue whale, which can reach , and the fin wha ...
s than the bowhead and
right whale Right whales are three species of large baleen whales of the genus ''Eubalaena'': the North Atlantic right whale (''E. glacialis''), the North Pacific right whale (''E. japonica'') and the Southern right whale (''E. australis''). They are clas ...
s. The pygmy right whale is found in temperate waters of the Southern Hemisphere, and feeds on
copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...
s and
euphausiid Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are consi ...
s. Little is known about its population or social habits. Unlike most other baleen whales, it has rarely been subject to exploitation.


Taxonomy

During the 1839-43 voyage of
James Clark Ross Sir James Clark Ross (15 April 1800 – 3 April 1862) was a British Royal Navy officer and polar explorer known for his explorations of the Arctic, participating in two expeditions led by his uncle John Ross, and four led by William Edwa ...
, naturalists found bones and baleen plates resembling a smaller version of the
right whale Right whales are three species of large baleen whales of the genus ''Eubalaena'': the North Atlantic right whale (''E. glacialis''), the North Pacific right whale (''E. japonica'') and the Southern right whale (''E. australis''). They are clas ...
. In his ''Zoology of the Voyage of HMS Erebus and Terror'' (1846),
John Edward Gray John Edward Gray, FRS (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used for ...
described the new species, naming it ''Balaena marginata''. In 1864, Gray established a new genus (''Caperea'') after receiving a skull and some bones of another specimen. Six years later, in 1870, he added the name ''Neobalaena''. He soon realized the three species were one and the same: ''Caperea marginata'' (''caperea'' means "wrinkle" in Latin, "referring to the wrinkled appearance of the ear bone"; while ''marginata'' translates to "enclosed with a border", which "refers to the dark border around the baleen plates of some individuals"). In research findings published on December 18, 2012, paleontologist Felix Marx compared the skull bones of pygmy right whales to those of extinct cetaceans, finding it to be a close relative to the
Cetotheriidae Cetotheriidae is a family of baleen whales (parvorder Mysticeti). The family is known to have existed from the Late Oligocene to the Early Pleistocene before going extinct. Although some phylogenetic studies conducted by recovered the livin ...
, making the pygmy right whale a
living fossil A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossi ...
. In 2012, Italian palaeontologist Michelangelo Bisconti described '' Miocaperea pulchra'', a first fossil pygmy right whale from Peru. This new genus differs from the living genus in some cranial details, but Bisconti's study confirmed the monophyly of the Neobalaenidae and he concluded that the rorqual-like features in ''C. marginata'' must be the result of parallel evolution. The presence of a fossil neobalaenid some north of the known range of ''C. marginata'', suggests that environmental change has caused a southern shift in neobalaenid distribution. A second, undescribed species was tentatively assigned to Neobalaenidae in 2012.


Description

The pygmy right whale is rarely encountered and consequently little studied. However, it is known that it is by far the smallest of the baleen whales. Calves are estimated to be about to at birth (an approximately fetus was reported from a female that had stranded in Perkins Bay, Tasmania, in 1982). By the time they are weaned, they may be about long. It is believed they become sexually mature at about and physically mature at about . The longest male registered, was a individual which had stranded in Cloudy Bay, Tasmania, while the longest female was a individual which had stranded in
Stanley, Tasmania Stanley is a town on the north-west coast of Tasmania, Australia. It is the second-last major township on the north-west coast when travelling west, Smithton being the larger township in the Circular Head municipality. According to the , Stanley ...
in 1981. Pygmy right whales can weigh as much as . A female weighed and a male weighed . Gestation and lactation periods and longevity are all unknown. Part of the reason for the scarcity of data may be the relative inactivity of the whale, making location for study difficult. The blow is small and indistinct and the whale is usually a slow undulating swimmer, although capable of bursts of acceleration. The coloring and shape of the pygmy right whale, dark gray dorsally and lighter gray ventrally, commonly with a pair of chevron-shaped lighter patches behind the eyes, is similar to that of the dwarf minke and
Antarctic minke whale The Antarctic minke whale or southern minke whale (''Balaenoptera bonaerensis'') 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 whal ...
s and at sea the species may easily be confused with these two species, in case the jaw and flippers are not carefully observed. The arched jawline is not as pronounced as other
right whale Right whales are three species of large baleen whales of the genus ''Eubalaena'': the North Atlantic right whale (''E. glacialis''), the North Pacific right whale (''E. japonica'') and the Southern right whale (''E. australis''). They are clas ...
s and may not be sufficient to distinguish a pygmy right whale from a minke whale. The long, narrow cream-coloured baleen plates with a distinctive white gumline are the most effective discriminators. Unlike true right whales, pygmy rights do not have callosities. The
dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...
is falcate (crescent-shaped) and located about three-quarters of the way along the back of the animal. Unlike the minke whales, occasionally the dorsal will not be seen on the whale surfacing. Like the minkes, though, it doesn't raise its flukes when it dives. The skull and skeleton of the pygmy right whale is unlike those of any other extant whale: the
supraoccipital shield The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cereb ...
extends farther posteriorly; the ear bone has a lateral wrinkle and is roughly square in outline. All seven cervical vertebrae are fused, and the pygmy right has only 44 vertebrae. The 18 pairs of ribs are broad and flat, and make up 39–45% of the vertebral column (compared to 33% in other mysticetes). Each thoracic vertebrae has a pair of huge wing-like transverse processes, many of which overlap. The dorsal end of the ribs are remarkably thin and almost fail to make contact with the transverse processes. The reduced tail (or sacrocaudal region) features a vestigial pelvis and small chevron bones. The flippers have four digits. The lungs and heart are relatively small, which suggests that the pygmy right whale is not a deep diver. The larynx is reported to be different from any other cetacean. Like other mysticetes, the pygmy right whale has a large laryngeal sac, but in contrast to other mysticetes, this sac is positioned on the right side of the midline in the pygmy right. The presence of this laryngeal sac can possibly be the explanation for the long thorax and flattened ribs, but the peculiar ribs have led to multiple speculations as to their origin.


Behavior and ecology

Analysis of the stomach contents of dead pygmy right whales indicates that it feeds on
copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...
s and
euphausiid Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are consi ...
s (krill). The social and mating structures are unknown. The whale is typically seen alone or in pairs, sometimes associated with other cetaceans (including dolphins,
pilot whale Pilot whales are cetaceans belonging to the genus ''Globicephala''. The two extant species are the long-finned pilot whale (''G. melas'') and the short-finned pilot whale (''G. macrorhynchus''). The two are not readily distinguishable at sea, a ...
s,
minke whale The minke whale (), or lesser rorqual, is a species complex of baleen whale. The two species of minke whale are the common (or northern) minke whale and the Antarctic (or southern) minke whale. The minke whale was first described by the Danish n ...
s, and once a
sei whale The sei whale ( , ; ''Balaenoptera borealis'') 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 ...
cow and calf). Occasionally larger groups are seen — in 2001 a group of 14 were seen at 46°S in the South Pacific about 450 km southeast of New Zealand, while in 1992 a group of about 80 individuals were seen southwest of
Cape Leeuwin Cape Leeuwin is the most south-westerly (but not most southerly) mainland point of the Australian continent, in the state of Western Australia. Description A few small islands and rocks, the St Alouarn Islands, extend further in Flinders Ba ...
and another group of over 100 individuals were sighted in June 2007 about southwest of
Portland, Victoria Portland is a city in Victoria, Australia, and is the oldest European settlement in the state. It is also the main urban centre in the Shire of Glenelg and is located on Portland Bay. As of the 2021 census the population was 10,016, increasing ...
. The flukes, blubber, and baleen plates of a pygmy right whale calf were found in 7.47 m (24.5 ft)
killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white pa ...
caught by whalers off South Africa.


Population and distribution

The pygmy right whale is among the least studied cetaceans; until 2008, fewer than 25 sightings of the species had been made at sea. The species lives in the Southern Hemisphere and is believed to be
circumpolar Circumpolar may refer to: * Antarctic region ** Antarctic Circle ** the Antarctic Circumpolar Current ** Subantarctic ** List of Antarctic and subantarctic islands ** Antarctic Convergence ** Antarctic Circumpolar Wave ** Antarctic Ocean * Arctic ...
, living in a band from about 30°S to 55°S in areas with surface water temperatures between . Individuals have been found on the coasts of
Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
,
Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of the Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of the main island, Isla G ...
,
Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...
,
South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...
,
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
and
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
. One group may be a year-round resident off
Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...
. The total population is unknown.


Whaling and whale-watching

On account of its relatively small size and sparse distribution, the pygmy right whale has rarely been taken by whalers. A male was taken off South Africa in 1917, and a couple were caught for scientific purposes by
Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
whalers in the
South Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
in 1970. Also a few pygmy right whales are known to have been caught in fishing nets. These factors are not believed to have had a significant impact on the population. Most data about pygmy right whales come from individual specimens washed up on coastlines; they are rarely encountered at sea and so they are not the primary subject of any
whale watching Whale watching is the practice of observing whales and dolphins ( cetaceans) in their natural habitat. Whale watching is mostly a recreational activity (cf. birdwatching), but it can also serve scientific and/or educational purposes.Hoyt, E. 2 ...
cruises.


Conservation

The pygmy right whale is listed on Appendix II Appendix II
" of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008. Effective: 5 March 2009.
of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). It is listed on Appendix II, as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements. The pygmy right whale is also covered by Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region ( Pacific Cetaceans MOU).


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


Further reading

* ''Encyclopedia of Marine Mammals'', Perrin Wursig and Thewissen (eds). * ''Whales, Dolphins and Porpoises'', Mark Carwardine. * ''National Audubon Society Guide to Marine Mammals of the World''.


External links

* {{DEFAULTSORT:pygmy right whale Baleen whales Cetaceans of the Pacific Ocean Mammals described in 1846 Taxa named by John Edward Gray