Perrin's beaked whale

Species (main)

Published: May 3, 2011, 12:00 am

Updated: September 7, 2011, 2:53 pm

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Species (main) Marine Ecology (main) Biogeography (main) Oceans and seas (main) Predator and Prey (main) Biodiversity (main) Wildlife (main)

Perrin's beaked whale. Source: Wurtz-Artescienza

Perrin's beaked whale (scientific name: Mesoplodon perrini) is one of 21 species of beaked whales (Hyperoodontidae or Ziphiidae), medium-sized whales with distinctive, long and narrow beaks and dorsal fins set far back on their bodies. They are marine mammals within the order of cetaceans.

Perrin's beaked whale was only identified as a species in recent years as a result of five animals that were stranded on the California coast between 1975 and 1997. They are a rarely seen cetacean and very little is known about the species.

Perrin's beaked whale. Source: Marine Bio

Size comparison of an average human against Hector's beaked whale which is similar in size to Perrin's beaked whale. Source: Chris Huh

Conservation Status: Data Deficient

Scientific Classification Kingdom: Animalia Phylum:--- Chordata Class:------ Mammalia Order:-------- Cetacea Family:-------- Hyperoodontidae Genus:--------- Mesoplodon Species:-------- 'Mesoplodon perrini (Dalebout, Mead, Baker, Baker and van Helden, 2002)

Common Names: California beaked whale Perrin's beaked whale

Physical Description

Overview physical features of the species are: Endothermic metabolism; Homoiothermic metabolism; and bilateral symmetry. Perrin's beaked whale is similar in shape to other members of this genus, with a short head and tail, a long abdomen, and a deep caudal peduncle. Like its closest relatives, Hector's beaked whale and the Peruvian beaked whale, it has a relatively short snout.

It has a crescent-shaped blowhole with the tips facing towards the head. The mouth forms a straight line, and a series of grooves are present along the throat. As adults, M. perrini have dark gray coloration on their backs which grades to white on their undersides. The ventral side of their tail flukes is a lighter shade of grey with striations. Juvenile type specimens have a somewhat different color pattern, with a white area around the throat and a dark grey patch around the rostrum and eyes.

Only the original five beached specimens have been accurately measured. The adult female was approximately 4.4 meters from nose to tail, while the adult male was 3.9 meters in length. The other three specimens were juvenile males, which were measured at 2.1, 2.2, and 2.4 meters. (Dalebout et al., 2002)

Like other Mesoplodon, male Perrin's beaked whales have a set of tusk-like teeth that originate from the lower jaw. These tusks are not present in females. It is thought that these ornamentation features play a role in intrasexual competition, as is evidenced by a series of long, white scars along the flank of the adult male type specimen. The tusks may also help these whales distinguish individuals belonging to their species from those of similar, sympatric species. (Dalebout et al., 2002; MacLeod, 2000)

Perrin's beaked whale is similar in appearance to a related species, Hector's beaked whale In fact, many of the type specimens of this species were originally identified as the latter species, and were only designated as a separate species by Dalebout in 2002. Morphological characteristics that set these two species apart include minor differences in the cranium, teeth, and mandible. (Dalebout et al., 2002)

Most of the characteristics that set Perrin's beaked whale apart from related species are molecular. Substantial differences in mtDNA and cytochrome b form the basis for its diagnosis as a new species. Morphological similarities suggested that the closest relative of Perrin's beaked whale was Hector's beaked whale. However, based on the molecular characters, Dalebout et al. concluded that its true sister species is the Peruvian beaked whale. This conclusion was later supported by analysis of nuclear actin sequences by Dalebout et al. (2004). (Dalebout et al., 2002; Dalebout et al., 2004)

Behaviour

Key species behaviours are: Natatoria and social. Sightings of Perrin's beaked whale or any other mesoplodont whales in the wild are extremely rare, as they spend most of their lives in the open ocean and tend to stay far away from boats on the rare occasions that they are sighted. Consequently, what we know of their behavior comes from a few eyewitness reports and evidence found on type specimens. (Dalebout et al., 2002; MacLeod, 2000)

Mesoplodon tend to be less social than other Odontoceti, such as dolphins or porpoises. Sightings of a related species, Stejneger's beaked whale, reveal that, while these whales are often found alone or in small groups, they can form pods of as many as 15 individuals. Members of these pods tend to stay extremely close to one another, appearing to be almost touching each other, and they surface or dive together. (Loughlin and Perez, 1985)

It is suspected that male Perrin's beaked whales frequently fight with one another, as is the case with other members of their genus. This is supported by parallel linear scars present on the flank of the adult male type specimen. These markings were probably made with a single tooth, which is unusual considering that this species has apical teeth. (Dalebout et al., 2002)

Home Range: Little is currently known about the home ranges of Perrin's beaked whale. There is some evidence that this species is migratory or nomadic, but this has yet to be confirmed. (Dalebout et al., 2002)

Vocalization and Communication

Although little is known about how Perrin's beaked whale communicates, research on other species of Mesoplodon indicates that they have the ability to echolocate. A 2004 study involving tagged Blainvilles beaked whale found that these animals are very vocal, most frequently emitting ultrasonic clicks that are well outside the range of human hearing. This research also revealed that these whales only emit clicks when they are below 200 meters depth, where they most commonly forage. (Johns et al., 2004)

Communication Channels utilized by this species are chiefly acoustic. Perception channels include:' tactile; acoustic; echolocation; and chemical.

Lifespan

Since Perrin's beaked whale is such an elusive species, as is typical of this genus, very little is known about its longevity and life history.

Reproduction

Key reproductive features of the species are: Iteroparous; Gonochoric/gonochoristic/dioecious (sexes separate); Viviparous. There is currently little information available regarding reproductive habits of Perrin's beaked whale or other beaked whales. The two adult type specimens were both sexually mature, and an analysis of the teeth indicated an approximate age of nine years for both of them. (Dalebout et al., 2002)

Relatively little is known about parental investment in Perrin's beaked whale. However, the 2.1 meter type specimen had a fringed tongue, which indicates that it was not yet weaned when it died. Researchers suspect that it was the calf of the adult female type specimen, and that it was still dependent on her when she was stranded. Like all other Cetacea, young are able to swim soon after birth. (Dalebout et al., 2002)

Distribution and Movements

File:Distribution of PerrinAt present, Perrin's beaked whales (Mesoplodon perrini) are only found in the northern Pacific Ocean. Four of the five known specimens of this whale species were found stranded along the coast of southern [[California] ]within 85 kilometers of one another in the late 1970's. Although this suggests an eastern distribution within the North Pacific, there is currently too little information to come to any firm conclusions. Scars attributed to cookie cutter sharks (Isistius) that were found on one of the type specimens indicates thatPerrin's beaked whale may migrate through tropical regions where this shark is found in surface waters. However, it could also indicate a more northern distribution of Isistius. (Dalebout et al., 2002)

Habitat

Like most other Ziphiidae, Perrin's beaked whale is chiefly pelagic, spending the majority of its time in deep oceanic waters over 1000 meters in depth. (Dalebout et al., 2002) The waters inhabited are primarily temperate seas.

Feeding Habits

At present, there is limited information regarding the diet and feeding habits of Perrin's beaked whale. However, it is suspected that these whales feed primarily on certain squid, mollusk and fish species, as do many other Ziphiidae. This is supported by gut content analysis of two of the type specimens. One contained the eye lens of a squid, and the other contained two squid beaks (identifed as Octopoteuthis deletron) and unidentified vertebrate parts. (Dalebout et al., 2002)

Predation

The only known predators ofPerrin's beaked whale are sharks and humans. Scars left bysp cookiecutter shark bites (Isistius) were present on one of the type specimens, but they did not appear to have caused any lasting damage. Although Mesoplodon were never harvested commercially, there have been reports of them being taken by humans from time to time. (Dalebout et al., 2002)

Threats and Conservation Status

Since so little is known about the habits ofPerrin's beaked whale, and so few individuals have been encountered in the wild, it is difficult to adequately evaluate how many individuals are left and what potential threats (if any) there are to the survival of the species. According to the ICUN, this species has the potential to become caught in certain types of fishing gear, such as deepwater gill nets used for capturing large pelagic [[fish] species]. Like other marine mammals, it may also be negatively impacted by navy sonar and loud noises generated by seismic exploration. The IUCN Red List lists the species asNot Evaluated. The USA Federal List states the species as having no special status. CITES lists the species inAppendix II.

References

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Citation

Encyclopedia of Life (2011). Perrin's beaked whale. ed. C.Michael Hogan. Encyclopedia of Earth. National Council for Science and Environment. Washington DC. Retrieved from http://editors.eol.org/eoearth/wiki/Perrin's_beaked_whale