Perrin's Beaked Whale
Encyclopedia
Perrin's beaked whale is the newest species
of beaked whale
to be described. The first two specimens were found in May 1975 stranded on the California
coast, with two more specimens being found in 1978 and 1979, and the last in September 1997. They were initially identified as Hector's beaked whale
(Mesoplodon hectori), except for the most recent one, which was assumed to be a neonate Cuvier's beaked whale
.
Following inclusion of one of these specimens in a mtDNA sequence
database of beaked whales, it turned out that they seemed well distinct from M. hectori (Dalebout et al. 1998). The other "Hector's" specimens from California were subsequently confirmed to belong to the same undescribed taxon
(Dalebout 2002). The new species was formally described in 2002 by Dalebout et al.; its common and specific names are a tribute to cetologist William F. Perrin.
Despite the superficial similarities to the (entirely allopatric) Hector's beaked whale, this species is closely related to the pygmy beaked whale
, the next most-recently described species, and probably represents its Northern Hemisphere
sister species.
Perrin's beaked whale has not definitely been recorded alive by scientists. However, its appearance is known from the beached specimens, and following resolution of their identity as a new species, it seems highly likely the three supposed Hector's beaked whales, which were seen off California in 1976 (two individuals) and 1978 (one individual), were actually this species (Mead 1981, Dalebout et al. 2002).
This species has a fairly typical body shape for a mesoplodont, with a small head, long body, and deep tail. The rostrum of this whale is shorter than every other mesoplodont other than Hector's and the pygmy beaked whales, especially in young individuals. The mouthline of this species is straight, and the melon forms a small bulge with a crescent-shaped blowhole
with forward-pointing tips. The teeth on this species are fairly large and towards the tip of the mouth. Throat grooves are present on this species. The mature male specimen was 3.9 metres in length (13 feet) and the female was 4.4 metres (14 feet 8 inches) in length; the immature males measured between 2.1 and 2.45 metres (7-7.5 ft).
The coloration is dark gray above and white below in the holotype
male, with a lighter gray underside of the tail fluke. A white patch is present near the navel. The colouration of females is not known, since the only specimen was rather decomposed.
Calves are light to dark gray on top, and white below, including the lower jaw and throat; the underside of the flukes is lighter gray. There is a dark "mask" on the head, from the corners of the mouth to the eye region, the rostrum, and the melon, and there are white stripes on the tail underside. The adult male had the typical white scar-stripes from fights with conspecifics. Only adult males seem to have teeth, and even these only two, in line with other Mesoplodon species. In Perrin's beaked whale, the teeth are located near the tip of the lower jaw and are roughly equilateral triangles when viewed laterally and still placed in the jaw; in this they resemble the foreteeth of Baird's beaked whale more than those of the Mesoplodon species which are otherwise similar.(Dalebout et al. 2002)
A photograph of a possible living specimen - one of the two observed in 1976 - is featured in Rice (1978: 95) as "Mesoplodon carlhubbsi", a distinctly larger species also native to the waters off California. Recordings of the animals' vocalizations were also made on this opportunity.(Mead 1981)
. It likely lives offshore the Pacific coast of North America
- and possibly elsewhere in the northern Pacific - in waters 1,000 meters deep or more. However, evidence is lacking and the northern and southern limits of its range are entirely unknown (though biogeography
of beaked whales suggests it does not reach the Equator
). No population estimate or assessment of conservation status has hitherto been possible. San Clemente Island
holds a sonar
research facility of the US Navy; such research has in the past been implicated in causing strandings
of cetaceans.
The males of this species seem to engage in fights like most other mesoplodonts. Scars from fighting are present on this species, although the precise mechanism of combat is enigmatic: given the teeth's position near the lower jaw tips, it can be expected that the scars consist of two parallel lines; only single scar lines were present on the adult male, however, suggesting glancing blows rather than direct attacks created them.
Few stomach contents were available for analysis. Presumably, this species eats pelagic squid
(such as Octopoteuthis deletron
, remains of which were found in the female's stomach) and possibly small fish
like other beaked whales.
The largest immature LACM 088901, at 2.45 metres of length, was apparently independent from its mother. On the other hand, the smallest known specimen, USNM 504259, had a fringed tongue which indicated it was still suckling. Teeth were not present in the immatures, but they are not needed for feeding. The dates when the specimens were found suggest the young start to feed independently in summer; considering most whales suckle until around one year of age, this suggests the young are born during the summer half of the year. Consequently, as they are all of somewhat similar size, the immatures were probably around one year old. The adults were both an estimated 9 years old when they died.
The causes of death of two animals can be tentatively inferred; the 1997 specimen was starving at the time of death, possibly following a parasite infection (Dalebout et al. 2002). The 1975 female had died around May 14 (Mead 1981); given that the juvenile found on May 22 was apparently its calf and that it was not yet fully weaned, its death seems to be a direct consequence of the loss of its mother.
As with their relatives, cookiecutter shark
s attack this whale to try and bite off chunks of flesh. Such attacks are generally not life-threatening to the whale. It is a host of the thoracica
n barnacle
Conchoderma auritum, and for one or several species of parasitic Phyllobothrium cestodes (possibly Phyllobothrium delphini), this species is either a primary or a dead-end host
.
The 1976 possible sightings took place on July 30, the 1978 one on September 9 - the same day the holotype specimen was discovered (Mead 1981). Altogether, there is a marked concentration of sightings between May and September. It is unknown if this has any significance. Nonetheless, with the scant data at hand, it still appears that looking for small beaked whales during the summer months in the area between Santa Catalina
and San Clemente Island
s and the mainland has the best odds of encountering this enigmatic species.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of beaked whale
Beaked whale
Beaked whales are 21 species of toothed whales, members of the family Ziphiidae, are notable for their elongated beaks. Beaked whales are one of the world's most extreme divers. They can dive for long periods—20 to 30 minutes is common, and 85 minute dives have been recorded—and to...
to be described. The first two specimens were found in May 1975 stranded on the California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
coast, with two more specimens being found in 1978 and 1979, and the last in September 1997. They were initially identified as Hector's beaked whale
Hector's Beaked Whale
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...
(Mesoplodon hectori), except for the most recent one, which was assumed to be a neonate Cuvier's beaked whale
Cuvier's Beaked Whale
Cuvier's beaked whale is the most widely distributed of all the beaked whales. It is the only member of the genus Ziphius. Another common name for the species is goose-beaked whale because its head is said to be shaped like the beak of a goose. Georges Cuvier first described it in 1823 from part...
.
Following inclusion of one of these specimens in a mtDNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
database of beaked whales, it turned out that they seemed well distinct from M. hectori (Dalebout et al. 1998). The other "Hector's" specimens from California were subsequently confirmed to belong to the same undescribed taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
(Dalebout 2002). The new species was formally described in 2002 by Dalebout et al.; its common and specific names are a tribute to cetologist William F. Perrin.
Despite the superficial similarities to the (entirely allopatric) Hector's beaked whale, this species is closely related to the pygmy beaked whale
Pygmy Beaked Whale
The pygmy beaked whale , also known as the bandolero beaked whale, Peruvian beaked whale and lesser beaked whale, is the smallest of the mesoplodonts and one of the newest discoveries. There were at least two dozen sightings of an unknown beaked whale named Mesoplodon sp...
, the next most-recently described species, and probably represents its Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
sister species.
Perrin's beaked whale has not definitely been recorded alive by scientists. However, its appearance is known from the beached specimens, and following resolution of their identity as a new species, it seems highly likely the three supposed Hector's beaked whales, which were seen off California in 1976 (two individuals) and 1978 (one individual), were actually this species (Mead 1981, Dalebout et al. 2002).
Description
Perrin's beaked whales cannot be identified with absolute certainty at sea. However, the combination of small size, appearance and presumed range makes a confusion unlikely. Stranded specimens can be identified as this species by either DNA sequence data and/or anatomical details of the skull.(Dalebout et al. 2002)This species has a fairly typical body shape for a mesoplodont, with a small head, long body, and deep tail. The rostrum of this whale is shorter than every other mesoplodont other than Hector's and the pygmy beaked whales, especially in young individuals. The mouthline of this species is straight, and the melon forms a small bulge with a crescent-shaped blowhole
Blowhole (biology)
In biology, a blowhole is the hole at the top of a cetacean's head through which the animal breathes air. It is homologous with the nostril of other mammals. As whales reach the water surface to breathe, they will forcefully expel air through the blowhole. Not only is air expelled, but mucus and...
with forward-pointing tips. The teeth on this species are fairly large and towards the tip of the mouth. Throat grooves are present on this species. The mature male specimen was 3.9 metres in length (13 feet) and the female was 4.4 metres (14 feet 8 inches) in length; the immature males measured between 2.1 and 2.45 metres (7-7.5 ft).
The coloration is dark gray above and white below in the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
male, with a lighter gray underside of the tail fluke. A white patch is present near the navel. The colouration of females is not known, since the only specimen was rather decomposed.
Calves are light to dark gray on top, and white below, including the lower jaw and throat; the underside of the flukes is lighter gray. There is a dark "mask" on the head, from the corners of the mouth to the eye region, the rostrum, and the melon, and there are white stripes on the tail underside. The adult male had the typical white scar-stripes from fights with conspecifics. Only adult males seem to have teeth, and even these only two, in line with other Mesoplodon species. In Perrin's beaked whale, the teeth are located near the tip of the lower jaw and are roughly equilateral triangles when viewed laterally and still placed in the jaw; in this they resemble the foreteeth of Baird's beaked whale more than those of the Mesoplodon species which are otherwise similar.(Dalebout et al. 2002)
A photograph of a possible living specimen - one of the two observed in 1976 - is featured in Rice (1978: 95) as "Mesoplodon carlhubbsi", a distinctly larger species also native to the waters off California. Recordings of the animals' vocalizations were also made on this opportunity.(Mead 1981)
Distribution and status
This species has only been found off the coast of California between San Diego and MontereyMonterey, California
The City of Monterey in Monterey County is located on Monterey Bay along the Pacific coast in Central California. Monterey lies at an elevation of 26 feet above sea level. As of the 2010 census, the city population was 27,810. Monterey is of historical importance because it was the capital of...
. It likely lives offshore the Pacific coast of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
- and possibly elsewhere in the northern Pacific - in waters 1,000 meters deep or more. However, evidence is lacking and the northern and southern limits of its range are entirely unknown (though biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
of beaked whales suggests it does not reach the Equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
). No population estimate or assessment of conservation status has hitherto been possible. San Clemente Island
San Clemente Island
San Clemente Island is the southernmost of the Channel Islands of California. It is owned and operated by the United States Navy, and is a part of Los Angeles County. Defined by the United States Census Bureau as Block Group 2 of Census Tract 5991 of Los Angeles County, California, it is long and...
holds a sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
research facility of the US Navy; such research has in the past been implicated in causing strandings
Beached whale
A beached whale is a whale that has stranded itself on land, usually on a beach. Beached whales often die due to dehydration, the body collapsing under its own weight, or drowning when high tide covers the blowhole.-Species:...
of cetaceans.
Ecology and behavior
Nothing is known of this species' behavior in life. However, as this is apparently quite similar in all Mesoplodon, a number of well-founded assumptions can be made.The males of this species seem to engage in fights like most other mesoplodonts. Scars from fighting are present on this species, although the precise mechanism of combat is enigmatic: given the teeth's position near the lower jaw tips, it can be expected that the scars consist of two parallel lines; only single scar lines were present on the adult male, however, suggesting glancing blows rather than direct attacks created them.
Few stomach contents were available for analysis. Presumably, this species eats pelagic squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
(such as Octopoteuthis deletron
Octopoteuthis deletron
Octopoteuthis deletron is a species of squid in the genus Octopoteuthis. Found at depths of 400 to 800 m in the Pacific Ocean, they grow to at least 24 cm. Males find it difficult to detect the gender of other individuals they encounter in the dark depths, so they have adopted a strategy of...
, remains of which were found in the female's stomach) and possibly small fish
like other beaked whales.
The largest immature LACM 088901, at 2.45 metres of length, was apparently independent from its mother. On the other hand, the smallest known specimen, USNM 504259, had a fringed tongue which indicated it was still suckling. Teeth were not present in the immatures, but they are not needed for feeding. The dates when the specimens were found suggest the young start to feed independently in summer; considering most whales suckle until around one year of age, this suggests the young are born during the summer half of the year. Consequently, as they are all of somewhat similar size, the immatures were probably around one year old. The adults were both an estimated 9 years old when they died.
The causes of death of two animals can be tentatively inferred; the 1997 specimen was starving at the time of death, possibly following a parasite infection (Dalebout et al. 2002). The 1975 female had died around May 14 (Mead 1981); given that the juvenile found on May 22 was apparently its calf and that it was not yet fully weaned, its death seems to be a direct consequence of the loss of its mother.
As with their relatives, cookiecutter shark
Cookiecutter shark
The cookiecutter shark , also called the cigar shark, is a species of small dogfish shark in the family Dalatiidae. This shark occurs in warm, oceanic waters worldwide, particularly near islands, and has been recorded from as deep as . It migrates vertically up to every day, approaching the...
s attack this whale to try and bite off chunks of flesh. Such attacks are generally not life-threatening to the whale. It is a host of the thoracica
Thoracica
Thoracica is a superorder of crustaceans which contains the most familiar species of barnacles found on rocky coasts, such as Semibalanus balanoides and Chthamalus stellatus. They have six well-developed limbs, and may be either stalked or sessile. The carapace is heavily calcified...
n barnacle
Barnacle
A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have...
Conchoderma auritum, and for one or several species of parasitic Phyllobothrium cestodes (possibly Phyllobothrium delphini), this species is either a primary or a dead-end host
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
.
Specimens
- USNM 504259 - May 22, 1975; 33°15'N, 117°26'W - the smallest specimen, an immature male
- USNM504260 - May 28, 1975; 33°16'N, 117°26'W - an adult, the only female known to date and probably the mother of USNM 504259 (Dalebout et al. 2002)
- USNM504853 - September 9, 1978; 33°07'N, 117°20'W - an adult male, the holotypeHolotypeA holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
- LACM 088901Natural History Museum of Los Angeles CountyThe Natural History Museum of Los Angeles County opened in Exposition Park, Los Angeles, California, USA in 1913 as the Museum of History, Science, and Art. The moving force behind it was a museum association founded in 1910. Its distinctive main building, with fitted marble walls and domed and...
JRH 052 - December 27, 1979; 32°55'N, 117°15'W - an immature male - TMMC-C75Natural History Museum of Los Angeles CountyThe Natural History Museum of Los Angeles County opened in Exposition Park, Los Angeles, California, USA in 1913 as the Museum of History, Science, and Art. The moving force behind it was a museum association founded in 1910. Its distinctive main building, with fitted marble walls and domed and...
- September 18, 1997; 36°37'N, 121°55'W - an immature male
The 1976 possible sightings took place on July 30, the 1978 one on September 9 - the same day the holotype specimen was discovered (Mead 1981). Altogether, there is a marked concentration of sightings between May and September. It is unknown if this has any significance. Nonetheless, with the scant data at hand, it still appears that looking for small beaked whales during the summer months in the area between Santa Catalina
Santa Catalina Island, California
Santa Catalina Island, often called Catalina Island, or just Catalina, is a rocky island off the coast of the U.S. state of California. The island is long and across at its greatest width. The island is located about south-southwest of Los Angeles, California. The highest point on the island is...
and San Clemente Island
San Clemente Island
San Clemente Island is the southernmost of the Channel Islands of California. It is owned and operated by the United States Navy, and is a part of Los Angeles County. Defined by the United States Census Bureau as Block Group 2 of Census Tract 5991 of Los Angeles County, California, it is long and...
s and the mainland has the best odds of encountering this enigmatic species.