Күйірмұрын киттер: Сипаттамасы мен ерекшеліктері

Species of whale

The Cuvier's beaked whale, goose beaked whale, or ziphius (Ziphius cavirostris) 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 (like orca and sperm whales)—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 , 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 , for 222 minutes. While likely diving to forage and hunt prey, such as cephalopods, and potentially evade predators (like the aforementioned orca), 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. Cuvier's beaked whale was named Ziphius cavirostris by Georges Cuvier based on a skull fragment which he believed to be a fossil from an extinct species. He reused the genus name Ziphius from an undetermined species mentioned by historical sources. The species name, cavirostris, comes from the Latin [[:wikt:cavus ("hollow") and [[:wikt:rostrum ("beak"), and refers to the bony cavity of the nares (nasal bones), now known as the prenarial basin. This feature is now known to be unique to male Z. cavirostrus. based on a skull collected on the Mediterranean coast of France at Fos sur mer, Bouches du Rhône, in 1804. He named it Ziphius cavirostris from the Latin cavus for "hollow", or "concave", referring to the prenarial basin, a deep hollow in the skull which is now known from only the males of the species. Cuvier's beaked whale is one of 22 species in the family Ziphiidae, and the only extant member of the genus Ziphius, with the other member being the extinct Ziphius compressus. Uniquely, no other species of ziphiid cetacean develops such dense rostral ossification of its prenarial basin. Sex determination in Cuvier’s beaked whales can be on the basis of genetics, observation of the genital area, the presence or absence of erupted teeth in adults, or presence of a calf. Pigmentation patterns can also give indications of gender. Adult males show a contrasted uniform white cape which usually extends to the dorsal fin zone. Individual coloration in adult males varies from dark to almost white. However, more than a third of adult females show "sharp" pigmentation patterns similar to adult males. Therefore males and females of this pattern cannot be distinguished using pigmentation pattern alone. The majority of adult females show a “soft” cluster of pigmentation features characterized by a brownish coloration and a shorter contrasting white cape. However, similar patterns have been observed in subadult animals of both sexes, so a "soft" pigmentation pattern alone is insufficient evidence to conclude that an animal is female. Cuvier's beaked whales at birth have a weight about and a length of Calves are black or dark blue with a white belly. Females reach maturity at an average length of and males at , weighing about 2 to 3.5 tons. Cuvier's beaked whale is an odontocete — or toothed whale. Erupted teeth are only present in the adult males. The frequency of scarring is higher in males than in females, and tends to increase with age. Cuvier's beaked whale holds the records for both the deepest and the longest dives ever documented for any mammal; in 2014, scientists reported that a Cuvier's beaked whale, off the coast of California, dove to 9816 feet (2992 m) below the ocean's surface, becoming the deepest documented dive for any mammal. A study in 2020 reported a Cuvier's beaked whale making a dive that lasted 222 minutes, the longest dive ever documented for any mammal. Supervising scientist Nicola Hodgkins noted that "the recorded dive time of more than three hours is likely not typical, and instead the result of an individual pushed to its absolute limits". Considering the species' ability to dive to almost 10000 feet (3048 m), and remain underwater for over two hours, at times, there are suggestions that they may likely be able to collapse or flatten their rib cage, and possibly their heart, lungs or other organs, while simultaneously decreasing their heart rate while at depth. They have been observed making a leaping flourish when entering a dive into the pelagic depths. During shallow dives, Cuvier's beaked whales tend to be silent, possibly to avoid predators. Past , they use echolocation as a hunting aid. It appears that Cuvier's beaked whale prefers diving deep and using a suction process to acquire fish. Diving deep to catch prey, Cuvier's beaked whales open their jaws, expand their throat and move their tongue in a way that creates a pressure change and sucks their prey, like squid and deep sea fish, directly into their mouths. This species possess throat pleats, somewhat like a rorqual, that allows its throat to expand, presumably aiding in generating a stronger suction force. Like a dolphin, it appears to wear a permanent smile due to its jaw structure. This means the whale can use sound waves to locate potential sources of food, which is helpful in the deep sea, where there is no sunlight. This deep diving with echolocation seems to help Cuvier's beaked whales avoid competition for their prey. Scientists have used beached specimens to study the whale's eating habits via stomach analysis. Prey of Cuvier’s beaked whales include Cranchiidae, Onychoteuthidae, Brachioteuthidae, Enoploteuthidae, Octopoteuthidae, and Histioteuthidae, as well as deep sea fish. Comparing the stomachs of the whales found in the Pacific Ocean to those found in the Mediterranean found that the Mediterranean whales predominantly ate squid from a 1,000 to 2,000 foot level, whereas in the Pacific, the whales found in Monterey, California in 2015, Taiwan in 1995, Alaska, and Baja California had access to much deeper water. As well as catching prey in the benthopelagic zone, they consumed a mixture of crustaceans and cephalopods further down in the bathypelagic zone. Molluscs and octopus only found in these deep sea regions are also sometimes eaten in the bathypelagic zone. A whale retrieved in Monterey in 2015 was observed to have eaten 200 squids, five fish, and one very deep sea shrimp. The shrimp and most of the squid were seemingly bathypelagic, and the fish were giant grenadiers off the benthopelagic ocean bottoms. The Mediterranean population might be genetically distinct from the North Atlantic population(s). Cuvier's beaked whale may be one of the most common and abundant of the beaked whales, with a worldwide population likely well over 100,000. An estimated 80,000 are in the eastern tropical Pacific, nearly 1,900 are off the west coast of the United States (excluding Alaska), and more than 15,000 are off Hawaii. as of 2019 this was rejected on the basis that there was insufficient scientific evidence to consider them a distinct population segment (DPS) under the Endangered Species Act (ESA).

Before 1955, it is estimated that Japanese whalers caught anywhere from 3 to 35 Cuvier's every year. From 1955 until the 1990s, more than 4,000 Cuvier's beaked whales were reportedly caught. The species has reportedly been caught incidentally in fisheries in Colombia, in the Italian swordfish fishery, and in a drift gillnet fishery off California and Oregon on the U. S. west coast, where between 22 and 44 individuals died each year from 1992 to 1995.

Cuvier's beaked whale seems to have a bad reaction to sonar. Strandings and beachings often occur near naval bases where sonar may have been in use. Cuvier's beaked whale has been observed in Hawaii avoiding diving for food or avoiding an area where sonar is in use. A higher incidence of strandings has been recorded in noisy seas such as the Mediterranean and multiple mass strandings have occurred following operations by the Spanish Navy in the Canary Islands. In 2019, a review of evidence on the mass strandings of beaked whales linked to naval exercises where sonar was used concluded the effects of mid frequency active sonar are strongest on Cuvier's beaked whales but vary among individuals or populations, and the strength of the whales' response may depend on whether the individuals had prior exposure to sonar. The report considered the most plausible explanation of the symptoms of decompression sickness such as gas embolism found in stranded whales to be the whales' response to sonar. It noted no more mass strandings had occurred in the Canary Islands once naval exercises using sonar were banned there, and recommended the ban be extended to other areas such as the Mediterranean, where mass strandings continue to occur.