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145-404: The orca ( Orcinus orca ), or killer whale , is a toothed whale and the largest member of the oceanic dolphin family. It is the only extant species in the genus Orcinus and is recognizable by its black-and-white patterned body. A cosmopolitan species , they are found in diverse marine environments, from Arctic to Antarctic regions to tropical seas. Orcas are apex predators with

290-579: A beached whale, resulting in eight of them developing botulism , with two of the affected requiring mechanical ventilation . This is a possibility for any meat taken from an unpreserved carcass. This is a list of large cetacean strandings (200 or more). On June 23, 2015, 337 dead whales were discovered in a remote fjord in Patagonia , southern Chile , the largest stranding of baleen whales to date. Three hundred and five bodies and 32 skeletons were identified by aerial and satellite photography between

435-965: A better chance of preventing their prey from escaping, which is killed by being thrown around, rammed and jumped on. Arctic orcas may attack beluga whales and narwhals stuck in pools enclosed by sea ice, the former are also driven into shallower water where juveniles are grabbed. By contrast, orcas appear to be wary of pilot whales , which have been recorded to mob and chase them. Nevertheless, possible predation on long-finned pilot whales has been recorded in Iceland , and one study suggests short-finned pilot whales are among Caribbean Orcas' prey. Killer whales have been recorded attacking short-finned pilot whales in Peru as well. Orcas also prey on larger species such as sperm whales , grey whales , humpback whales and minke whales . On three separate occasions in 2019 orcas were recorded to have killed blue whales off

580-426: A broad range of sounds using nasal airsacs located just below the blowhole. Clicks are directional and are used for echolocation, often occurring in a short series called a click train. The click rate increases when approaching an object of interest. Toothed whale biosonar clicks are amongst the loudest sounds made by marine animals . The cetacean ear has specific adaptations to the marine environment. In humans,

725-444: A burst of air into the water and allowing it to rise to the surface, forming a ring, or swimming repeatedly in a circle and then stopping to inject air into the helical vortex currents thus formed. They also appear to enjoy biting the vortex rings, so that they burst into many separate bubbles and then rise quickly to the surface. Dolphins are known to use this method during hunting. Dolphins are also known to use tools. In Shark Bay ,

870-444: A clade of cetaceans that includes dolphins , porpoises , and all other whales with teeth , such as beaked whales and the sperm whales . 73 species of toothed whales are described. They are one of two living groups of cetaceans, the other being the baleen whales (Mysticeti), which have baleen instead of teeth. The two groups are thought to have diverged around 34 million years ago (mya). Toothed whales range in size from

1015-533: A dead stranded animal in the Bay of Greifswald that had attracted a great deal of local interest. The orca is one of 35 species in the oceanic dolphin family , which first appeared about 11 million years ago. The orca lineage probably branched off shortly thereafter. Although it has morphological similarities with the false killer whale , the pygmy killer whale and the pilot whales , a study of cytochrome b gene sequences indicates that its closest extant relatives are

1160-456: A definitive reason for the behavior. However, a link between the mass beaching of beaked whales and use of mid-frequency active sonar has been found. Whales that die due to stranding can subsequently decay and bloat to the point where they can explode , causing gas and their internal organs to fly out. Every year, up to 2,000 animals beach themselves. Although the majority of strandings result in death, they pose no threat to any species as

1305-582: A diverse diet. Individual populations often specialize in particular types of prey. This includes a variety of fish , sharks , rays , and marine mammals such as seals and other dolphins and whales . They are highly social ; some populations are composed of highly stable matrilineal family groups (pods). Their sophisticated hunting techniques and vocal behaviors, often specific to a particular group and passed along from generation to generation, are considered to be manifestations of animal culture . The International Union for Conservation of Nature assesses

1450-439: A few, like the orca , feed on mammals, such as pinnipeds . Males typically mate with multiple females every year, making them polygynous . Females mate every two to three years. Calves are typically born in the spring and summer, and females bear the responsibility for raising them, but more sociable species rely on the family group to care for calves. Many species, mainly dolphins, are highly sociable, with some pods reaching over

1595-425: A male bottlenose dolphin tends to be similar to that of his mother, while the signature whistle of a female bottlenose dolphin tends to be more identifying. Bottlenose dolphins have a strong memory when it comes to these signature whistles, as they are able to relate to a signature whistle of an individual they have not encountered for over twenty years. Research done on signature whistle usage by other dolphin species

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1740-522: A matriline is 5.5 animals. Because females can reach age 90, as many as four generations travel together. These matrilineal groups are highly stable. Individuals separate for only a few hours at a time, to mate or forage. With one exception, an orca named Luna , no permanent separation of an individual from a resident matriline has been recorded. Closely related matrilines form loose aggregations called pods, usually consisting of one to four matrilines. Unlike matrilines, pods may separate for weeks or months at

1885-432: A mirror; then whether the animal shows signs of self-recognition is determined. In 1995, Marten and Psarakos used television to test dolphin self-awareness. They showed dolphins real-time footage of themselves, recorded footage, and another dolphin. They concluded that their evidence suggested self-awareness rather than social behavior. While this particular study has not been repeated since then, dolphins have since "passed"

2030-535: A mistranslation of the Spanish "asesino de ballenas" (literally "whale killer"), reflecting their historical predation on whales. Since the 1960s, the use of "orca" instead of "killer whale" has steadily grown in common use. The genus name Orcinus means "of the kingdom of the dead", or "belonging to Orcus ". Ancient Romans originally used orca (pl. orcae ) for these animals, possibly borrowing Ancient Greek ὄρυξ ( óryx ), which referred (among other things) to

2175-460: A more limited capacity for colour vision than most mammals. Most toothed whales have slightly flattened eyeballs, enlarged pupils (which shrink as they surface to prevent damage), slightly flattened corneas, and a tapetum lucidum ; these adaptations allow for large amounts of light to pass through the eye, and, therefore, a very clear image of the surrounding area. In water, a whale can see around 10.7 m (35 ft) ahead of itself, but they have

2320-536: A more limited repertoire. Individuals likely learn their dialect through contact with pod members. Family-specific calls have been observed more frequently in the days following a calf's birth, which may help the calf learn them. Dialects are probably an important means of maintaining group identity and cohesiveness. Similarity in dialects likely reflects the degree of relatedness between pods, with variation growing over time. When pods meet, dominant call types decrease and subset call types increase. The use of both call types

2465-473: A notice to mariners concerning the test. His report was published in March ;1998. Peter Tyack, of Woods Hole Oceanographic Institute , has been researching noise's effects on marine mammals since the 1970s. He has led much of the recent research on beaked whales ( Cuvier's beaked whales in particular). Data tags have shown that Cuvier's dive considerably deeper than previously thought, and are in fact

2610-410: A population of Indo-Pacific bottlenose dolphins put sponges on their beak to protect them from abrasions and sting ray barbs while foraging in the seafloor. This behaviour is passed on from mother to daughter, and it is only observed in 54 female individuals. Self-awareness is seen, by some, to be a sign of highly developed, abstract thinking. Self-awareness, though not well-defined scientifically,

2755-454: A protective circle around their calves with their flukes facing outwards, using them to repel the attackers. There is also evidence that humpback whales will defend against or mob orcas who are attacking either humpback calves or juveniles as well as members of other species. Prior to the advent of industrial whaling , great whales may have been the major food source for orcas. The introduction of modern whaling techniques may have aided orcas by

2900-438: A small bulge sitting on top of its skull, whereas a sperm whale's head is filled mainly with the melon. Directional asymmetry in the skull has been seen amongst many generations, used for echolocation. This asymmetry is useful in focusing the use of bio sonar effectively when deep diving for prey. Odontocetes are well adapted to hear sounds at ultrasonic frequencies, as opposed to mysticetes who generally hear sounds within

3045-570: A smaller range above water. They also have glands on the eyelids and outer corneal layer that act as protection for the cornea. The olfactory lobes are absent in toothed whales, and unlike baleen whales, they lack the vomeronasal organ , suggesting they have no sense of smell. Toothed whales are not thought to have a good sense of taste, as their taste buds are atrophied or missing altogether. However, some dolphins have preferences between different kinds of fish, indicating some sort of attachment to taste. Toothed whales are capable of making

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3190-541: A specific individual. These whistles are used in order for dolphins to communicate with one another by identifying an individual. It can be seen as the dolphin equivalent of a name for humans. These signature whistles are developed during a dolphin's first year; it continues to maintain the same sound throughout its lifetime. An auditory experience influences the whistle development of each dolphin. Dolphins are able to communicate to one another by addressing another dolphin through mimicking their whistle. The signature whistle of

3335-575: A thousand individuals. Once hunted for their products, cetaceans are now protected by international law. Some species are very intelligent . At the 2012 meeting of the American Association for the Advancement of Science , support was reiterated for a cetacean bill of rights, listing cetaceans as nonhuman persons . Besides whaling and drive hunting , they also face threats from bycatch and marine pollution. The baiji , for example,

3480-439: A threat to humans, and no fatal attack has ever been documented in their natural habitat. There have been cases of captive orcas killing or injuring their handlers at marine theme parks. Orcas also feature strongly in the mythologies of indigenous cultures, and their reputation in different cultures ranges from being the souls of humans to merciless killers. Orcas, despite being dolphins, are commonly called "killer whales" due to

3625-475: A time, then eating them one by one. Carousel feeding has been documented only in the Norwegian orca population, as well as some oceanic dolphin species. In New Zealand, sharks and rays appear to be important prey, including eagle rays , long-tail and short-tail stingrays , common threshers , smooth hammerheads , blue sharks , basking sharks , and shortfin makos . With sharks, orcas may herd them to

3770-794: A time. DNA testing indicates resident males nearly always mate with females from other pods. Clans, the next level of resident social structure, are composed of pods with similar dialects, and common but older maternal heritage. Clan ranges overlap, mingling pods from different clans. The highest association layer is the community, which consists of pods that regularly associate with each other but share no maternal relations or dialects. Transient pods are smaller than resident pods, typically consisting of an adult female and one or two of her offspring. Males typically maintain stronger relationships with their mothers than other females. These bonds can extend well into adulthood. Unlike residents, extended or permanent separation of transient offspring from natal matrilines

3915-538: A variety of techniques designed to stop them, such as the use of unbaited lines as decoys. Once, fishermen placed their boats several miles apart, taking turns retrieving small amounts of their catch, in the hope that the whales would not have enough time to move between boats to steal the catch as it was being retrieved. The tactic worked initially, but the orcas figured it out quickly and split into groups. In other anecdotes, researchers describe incidents in which wild orcas playfully tease humans by repeatedly moving objects

4060-452: A way that the animal's body shape is restored, and infection of such large wounds are rare. Toothed whales are fully aquatic creatures, which means their birth and courtship behaviours are very different from terrestrial and semiaquatic creatures. Since they are unable to go onto land to calve, they deliver their young with the fetus positioned for tail-first delivery. This prevents the calf from drowning either upon or during delivery. To feed

4205-450: A weight of over 10 t (9.8 long tons; 11 short tons). Calves at birth weigh about 180 kg (400 lb) and are about 2.4 m (7 ft 10 in) long. The skeleton of the orca is typical for an oceanic dolphin, but more robust. With their distinctive pigmentation, adult orcas are seldom confused with any other species. When seen from a distance, juveniles can be confused with false killer whales or Risso's dolphins . The orca

4350-496: A whale is beached near an inhabited locality, the rotting carcass can pose a nuisance as well as a health risk. Such very large carcasses are difficult to move. The whales are often towed back out to sea away from shipping lanes, allowing them to decompose naturally, or they are towed out to sea and blown up with explosives. Government-sanctioned explosions have occurred in South Africa, Iceland, Australia and United States. If

4495-414: A whale species, perhaps a narwhal . As part of the family Delphinidae , the species is more closely related to other oceanic dolphins than to other whales. They are sometimes referred to as "blackfish", a name also used for other whale species. "Grampus" is a former name for the species, but is now seldom used. This meaning of "grampus" should not be confused with the genus Grampus , whose only member

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4640-568: A whole. Only about ten cetacean species frequently display mass beachings, with ten more rarely doing so. All frequently-involved species are toothed whales (Odontoceti), rather than baleen whales (Mysticeti). These species share some characteristics which may explain why they beach. Body size does not normally affect the frequency, but both the animals' normal habitat and social organization do appear to influence their chances of coming ashore in large numbers. Odontocetes that normally inhabit deep waters and live in large, tightly knit groups are

4785-646: A year, dependency until one to two years, and maturity around seven to 10 years, all varying between the species. This mode of reproduction produces few offspring, but increases the survival probability of each one. Females, referred to as "cows", carry the responsibility of childcare, as males, referred to as "bulls", play no part in raising calves. Beached whale Several explanations for why cetaceans strand themselves have been proposed, including changes in water temperatures, peculiarities of whales' echolocation in certain surroundings, and geomagnetic disturbances, but none have so far been universally accepted as

4930-428: Is Risso's dolphin . Orcinus orca is the only recognized extant species in the genus Orcinus , and one of many animal species originally described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae . Konrad Gessner wrote the first scientific description of an orca in his Piscium & aquatilium animantium natura of 1558, part of the larger Historia animalium , based on examination of

5075-677: Is a behaviour in which a whale holds its head above water to view its surroundings. Resident orcas swim alongside porpoises and other dolphins . Orcas will engage in surplus killing , that is, killing that is not designed to be for food. As an example, a BBC film crew witnessed orca in British Columbia playing with a male Steller sea lion to exhaustion, but not eating it. Orcas are notable for their complex societies. Only elephants and higher primates live in comparably complex social structures . Due to orcas' complex social bonds, many marine experts have concerns about how humane it

5220-408: Is believed to be the precursor to more advanced processes like metacognitive reasoning (thinking about thinking) that are typical of humans. Research in this field has suggested that cetaceans, among others, possess self-awareness. The most widely used test for self-awareness in animals is the mirror test , in which a temporary dye is placed on an animal's body, and the animal is then presented with

5365-674: Is between single and multiple strandings. Many theories, some of them controversial, have been proposed to explain beaching, but the question remains unresolved. Whales have beached throughout human history, with evidence of humans salvaging from stranded sperm whales in southern Spain during the Upper Magdalenian era some 14,000 years before the present. Some strandings can be attributed to natural and environmental factors, such as rough weather, weakness due to old age or infection, difficulty giving birth, hunting too close to shore, or navigation errors. In 2004, scientists at

5510-867: Is called biphonation. The increased subset call types may be the distinguishing factor between pods and inter-pod relations. Dialects also distinguish types. Resident dialects contain seven to 17 (mean = 11) distinctive call types. All members of the North American west coast transient community express the same basic dialect, although minor regional variation in call types is evident. Preliminary research indicates offshore orcas have group-specific dialects unlike those of residents and transients. Norwegian and Icelandic herring -eating orcas appear to have different vocalizations for activities like hunting. A population that live in McMurdo Sound , Antarctica have 28 complex burst-pulse and whistle calls. Orcas have

5655-716: Is clearly in need of review, and it is likely that O. orca will be split into a number of different species or at least subspecies over the next few years." Although large variation in the ecological distinctiveness of different orca groups complicate simple differentiation into types, research off the west coast of North America has identified fish-eating "residents", mammal-eating "transients" and "offshores". Other populations have not been as well studied, although specialized fish and mammal eating orcas have been distinguished elsewhere. Mammal-eating orcas in different regions were long thought likely to be closely related, but genetic testing has refuted this hypothesis. A 2024 study supported

5800-603: Is common, with juveniles and adults of both sexes participating. Some males become "rovers" and do not form long-term associations, occasionally joining groups that contain reproductive females. As in resident clans, transient community members share an acoustic repertoire, although regional differences in vocalizations have been noted. As with residents and transients, the lifestyle of these whales appears to reflect their diet; fish-eating orcas off Norway have resident-like social structures, while mammal-eating orcas in Argentina and

5945-474: Is considered functionally extinct by IUCN , with the last sighting in 2004, due to heavy pollution to the Yangtze River . Whales sometimes feature in literature and film, as in the great white sperm whale of Herman Melville 's Moby-Dick . Small odontocetes, mainly dolphins, are kept in captivity and trained to perform tricks. Whale watching has become a form of tourism around the world. The tube in

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6090-587: Is difficult to estimate, but they clearly prefer higher latitudes and coastal areas over pelagic environments. Areas which serve as major study sites for the species include the coasts of Iceland , Norway, the Valdés Peninsula of Argentina, the Crozet Islands , New Zealand and parts of the west coast of North America, from California to Alaska . Systematic surveys indicate the highest densities of orcas (>0.40 individuals per 100 km) in

6235-440: Is herding, where a pod squeezes a school of fish into a small volume, known as a bait ball . Individual members then take turns plowing through the ball, feeding on the stunned fish. Coralling is a method where dolphins chase fish into shallow water to catch them more easily. Orcas and bottlenose dolphins have also been known to drive their prey onto a beach to feed on it, a behaviour known as beach or strand feeding. The shape of

6380-811: Is likely to be the result of scavenging remains dumped by whalers. One orca was also attacked by its companions after being shot. Although resident orcas have never been observed to eat other marine mammals, they occasionally harass and kill porpoises and seals for no apparent reason. Some dolphins recognize resident orcas as harmless and remain in the same area. Orcas do consume seabirds but are more likely to kill and leave them uneaten. Penguin species recorded as prey in Antarctic and sub-Antarctic waters include gentoo penguins , chinstrap penguins , king penguins and rockhopper penguins . Orcas in many areas may prey on cormorants and gulls . A captive orca at Marineland of Canada discovered it could regurgitate fish onto

6525-439: Is mainly limited to surfacing activities and milling (slow swimming with no apparent direction) after a kill. All members of a resident pod use similar calls, known collectively as a dialect . Dialects are composed of specific numbers and types of discrete, repetitive calls. They are complex and stable over time. Call patterns and structure are distinctive within matrilines. Newborns produce calls similar to their mothers, but have

6670-427: Is mostly black but with sharply bordered white areas. The entire lower jaw is white and from here, the colouration stretches across the underside to the genital area; narrowing and expanding some, and extending into lateral flank patches close to the end. The tail fluke (fin) is also white on the underside, while the eyes have white oval-shaped patches behind and above them, and a grey or white "saddle patch" exists behind

6815-412: Is one of the most accessible species for early cetologists , because it could be seen very close to land, inhabiting shallow coastal areas of Europe. Many of the findings that apply to all cetaceans were therefore first discovered in the porpoises. One of the first anatomical descriptions of the airways of the whales on the basis of a harbor porpoise dates from 1671 by John Ray. It nevertheless referred to

6960-449: Is only a single set of functional teeth (monophyodont dentition). Except for the sperm whale, most toothed whales are smaller than the baleen whales. The teeth differ considerably among the species. They may be numerous, with some dolphins bearing over 100 teeth in their jaws. At the other extreme are the narwhals with their single long tusks and the almost toothless beaked whales with tusk-like teeth only in males. In most beaked whales

7105-405: Is relatively limited. The research on other species done so far has yielded varied outcomes and inconclusive results. Sperm whales can produce three specific vocalisations: creaks, codas, and slow clicks. A creak is a rapid series of high-frequency clicks that sounds somewhat like a creaky door hinge. It is typically used when homing in on prey. A coda is a short pattern of 3 to 20 clicks that

7250-425: Is to keep them in captivity . Resident orcas in the eastern North Pacific live in particularly complex and stable social groups. Unlike any other known mammal social structure, resident whales live with their mothers for their entire lives. These family groups are based on matrilines consisting of the eldest female (matriarch) and her sons and daughters, and the descendants of her daughters, etc. The average size of

7395-400: Is used in social situations to identify one another (like a signature whistle), but it is still unknown whether sperm whales possess individually specific coda repertoires or whether individuals make codas at different rates. Slow clicks are heard only in the presence of males (it is not certain whether females occasionally make them). Males make a lot of slow clicks in breeding grounds (74% of

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7540-464: Is well adapted for both air and water, so much so that some can survive even if they are blind. Some species are well adapted for diving to great depths. Almost all have a layer of fat, or blubber , under the skin to keep warm in the cold water, with the exception of river dolphins . Toothed whales consist of some of the most widespread mammals, but some, as with the vaquita, are restricted to certain areas. Odontocetes feed largely on fish and squid, but

7685-519: Is well-adapted for hunting Arctic whales and calves. Bears are known to use sit-and-wait tactics, as well as active stalking and pursuit of prey on ice or water. Whales lessen the chance of predation by gathering in groups. This, however, means less room around the breathing hole as the ice slowly closes the gap. When out at sea, whales dive out of the reach of surface-hunting orca. Polar bear attacks on belugas and narwhals are usually successful in winter, but rarely inflict any damage in summer. For most of

7830-537: The Crozet Islands behave more like transients. Orcas of the same sex and age group may engage in physical contact and synchronous surfacing. These behaviours do not occur randomly among individuals in a pod, providing evidence of "friendships". Like all cetaceans , orcas depend heavily on underwater sound for orientation, feeding, and communication. They produce three categories of sounds: clicks, whistles, and pulsed calls. Clicks are believed to be used primarily for navigation and discriminating prey and other objects in

7975-507: The Crozet Islands , mothers push their calves onto the beach, waiting to pull the youngster back if needed. In March 2023, a female orca was spotted with a newborn pilot whale in Snæfellsnes . People who have interacted closely with orcas offer numerous anecdotes demonstrating the whales' curiosity, playfulness, and ability to solve problems. Alaskan orcas have not only learned how to steal fish from longlines , but have also overcome

8120-399: The Crozet Islands , orcas feed on South American sea lions and southern elephant seals in shallow water, even beaching temporarily to grab prey before wriggling back to the sea. Beaching, usually fatal to cetaceans, is not an instinctive behaviour, and can require years of practice for the young. Orcas can then release the animal near juvenile whales, allowing the younger whales to practice

8265-586: The Faroe Islands . In the Antarctic, orcas range up to the edge of the pack ice and are believed to venture into the denser pack ice, finding open leads much like beluga whales in the Arctic. However, orcas are merely seasonal visitors to Arctic waters, and do not approach the pack ice in the summer. With the rapid Arctic sea ice decline in the Hudson Strait , their range now extends deep into

8410-508: The Gulf of Penas and Puerto Natales , near the southern tip of South America . They may have been sei whales . This is one of only two or three such baleen mass stranding events in the last hundred years. It is highly unusual for baleen whales to strand other than singly, and these Patagonia strandings are tentatively attributed to an unusual cause such as ingestion of poisonous algae. In November 2018, over 140 whales were witnessed stranded on

8555-498: The Norwegian and Greenland sea specialize in herring and follow that fish's autumnal migration to the Norwegian coast. Salmon account for 96% of northeast Pacific residents' diet, including 65% of large, fatty Chinook . Chum salmon are also eaten, but smaller sockeye and pink salmon are not a significant food item. Depletion of specific prey species in an area is, therefore, cause for concern for local populations, despite

8700-574: The Spanish Navy was conducting exercises. Conversely, there were no mass strandings at other times. They did not propose a theory for the strandings. Fernández et al. in a 2013 letter to Nature reported that there had been no further mass strandings in that area, following a 2004 ban by the Spanish government on military exercises in that region. In May 1996, there was another mass stranding in West Peloponnese , Greece . At

8845-603: The University of Tasmania linked whale strandings and weather, hypothesizing that when cool Antarctic waters rich in squid and fish flow north, whales follow their prey closer towards land. In some cases predators (such as killer whales) have been known to panic other whales, herding them towards the shoreline. Their echolocation system can have difficulty picking up very gently-sloping coastlines. This theory accounts for mass beaching hot spots such as Ocean Beach, Tasmania and Geographe Bay , Western Australia where

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8990-401: The artiodactyl order (even-toed ungulates). They are closely related to the hippopotamus , sharing a common ancestor that lived around 54 million years ago (mya). The primitive cetaceans, or archaeocetes , first took to the sea approximately 49 mya and became fully aquatic by 5–10 million years later. The ancestors of toothed whales and baleen whales diverged in the early Oligocene. This

9135-613: The colossal squid , octopuses , and fish like demersal rays , but their diet is mainly medium-sized squid . Some prey may be taken accidentally while eating other items. A study in the Galápagos found that squid from the genera Histioteuthis (62%), Ancistrocheirus (16%), and Octopoteuthis (7%) weighing between 12 and 650 grams (0.026 and 1.433 lb) were the most commonly taken. Battles between sperm whales and giant squid or colossal squid have never been observed by humans; however, white scars are believed to be caused by

9280-413: The middle ear works as an impedance equalizer between the outside air's low impedance and the cochlear fluid's high impedance. In whales, and other marine mammals, no great difference exists between the outer and inner environments. Instead of sound passing through the outer ear to the middle ear, whales receive sound through the throat, from which it passes through a low-impedance, fat-filled cavity to

9425-475: The nominate subspecies . Four types have been documented in the Antarctic , Types A–D. Two dwarf species, named Orcinus nanus and Orcinus glacialis , were described during the 1980s by Soviet researchers, but most cetacean researchers are skeptical about their status. Complete mitochondrial sequencing indicates the two Antarctic groups (types B and C) should be recognized as distinct species, as should

9570-528: The 1.4 m (4 ft 7 in) and 54 kg (119 lb) vaquita to the 20 m (66 ft) and 100 t (98 long tons; 110 short tons) sperm whale . Several species of odontocetes exhibit sexual dimorphism , in that there are size or other morphological differences between females and males. They have streamlined bodies and two limbs that are modified into flippers. Some can travel at up to 20 knots. Odontocetes have conical teeth designed for catching fish or squid. They have well-developed hearing that

9715-505: The 1990s was controversially attributed by some scientists to orca predation, although with no direct evidence. The decline of sea otters followed a decline in seal populations, which in turn may be substitutes for their original prey, now decimated by industrial whaling. Orcas have been observed preying on terrestrial mammals , such as moose swimming between islands off the northwest coast of North America. Orca cannibalism has also been reported based on analysis of stomach contents, but this

9860-732: The 2000s that 2,321 orcas were in the seas around Japan. Orcas are apex predators , meaning that they themselves have no natural predators. They are sometimes called "wolves of the sea", because they hunt in groups like wolf packs. Orcas hunt varied prey including fish, cephalopods , mammals, seabirds , and sea turtles . Different populations or ecotypes may specialize, and some can have a dramatic impact on prey species. However, whales in tropical areas appear to have more generalized diets due to lower food productivity. Orcas spend most of their time at shallow depths, but occasionally dive several hundred metres depending on their prey. Fish-eating orcas prey on around 30 species of fish. Some populations in

10005-575: The Bahamas in March 2000 following a United States Navy sonar exercise. The Navy accepted blame agreeing that the dead whales experienced acoustically induced hemorrhages around the ears. The resulting disorientation probably led to the stranding. Ken Balcomb, a cetologist , specializes in the killer whale populations that inhabit the Strait of Juan de Fuca between Washington and Vancouver Island . He investigated these beachings and argues that

10150-765: The North Pacific transients, leaving the others as subspecies pending additional data. A 2019 study of Type D orcas also found them to be distinct from other populations and possibly even a unique species. Orcas are the largest extant members of the dolphin family. Males typically range from 6 to 8 m (20 to 26 ft) long and weigh in excess of 6 t (5.9 long tons; 6.6 short tons). Females are smaller, generally ranging from 5 to 7 m (16 to 23 ft) and weighing about 3 to 4 t (3.0 to 3.9 long tons; 3.3 to 4.4 short tons). Orcas may attain larger sizes as males have been recorded at 9.8 m (32 ft) and females at 8.5 m (28 ft). Large males can reach

10295-465: The age of 10 and reach peak fertility around 20, experiencing periods of polyestrous cycling separated by non-cycling periods of three to 16 months. Females can often breed until age 40, followed by a rapid decrease in fertility. Orcas are among the few animals that undergo menopause and live for decades after they have finished breeding. The lifespans of wild females average 50 to 80 years. Some are claimed to have lived substantially longer: Granny (J2)

10440-434: The average human brain which averages 1,450 cm (88 in ) in mature males. The brain to body mass ratio in some odontocetes, such as belugas and narwhals, is second only to humans. Dolphins are known to engage in complex play behaviour , which includes such things as producing stable underwater toroidal air-core vortex rings or " bubble rings ". Two main methods of bubble ring production are: rapid puffing of

10585-451: The brain homologous to where they are found in humans, suggesting they perform a similar function. Brain size was previously considered a major indicator of the intelligence of an animal. Since most of the brain is used for maintaining bodily functions, greater ratios of brain to body mass may increase the amount of brain mass available for more complex cognitive tasks. Allometric analysis indicates that mammalian brain size scales around

10730-678: The carcass is older, it is buried. In New Zealand, which is the site of many whale strandings, treaties with the indigenous Māori people allow the tribal gathering and customary (that is, traditional) use of whalebone from any animal which has died as a result of stranding. Whales are regarded as taonga (spiritual treasure), descendants of the ocean god, Tangaroa , and are as such held in very high respect. Sites of whale strandings and any whale carcasses from strandings are treated as tapu sites, that is, they are regarded as sacred ground. A beached whale carcass should not be consumed. In 2002, fourteen Alaskans ate muktuk (whale blubber) from

10875-399: The concentration of myoglobin than haemoglobin. Before going on long dives, many toothed whales exhibit a behaviour known as sounding; they stay close to the surface for a series of short, shallow dives while building their oxygen reserves, and then make a sounding dive. Toothed whale eyes are relatively small for their size, yet they do retain a good degree of eyesight. Also, the eyes are on

11020-470: The decline of these as well. Other marine mammal prey includes seal species such as harbour seals , elephant seals , California sea lions , Steller sea lions , South American sea lions and walruses . Often, to avoid injury, orcas disable their prey before killing and eating it. This may involve throwing it in the air, slapping it with their tails, ramming it, or breaching and landing on it. In steeply banked beaches off Península Valdés , Argentina, and

11165-431: The deepest-diving species of marine mammal yet known. At shallow depths Cuvier's stop vocalizing, either because of fear of predators, or because they don't need vocalization to track each other at shallow depths, where they have light adequate to see each other. Their surfacing behavior is highly unusual, because they exert considerable physical effort to surface by a controlled ascent, rather than passively floating to

11310-468: The difficult capture technique on the now-weakened prey. In the Antarctic, type B orcas hunt Weddell seals and other prey by "wave-hunting". They "spy-hop" to locate them on resting on ice floes, and then swim in groups to create waves that wash over the floe. This washes the prey into the water, where other orcas lie in wait. In the Aleutian Islands , a decline in sea otter populations in

11455-441: The dolphin to the sperm whale's spermaceti organ . These send out high-frequency clicks through the sound-modifying organs of the extramandibular fat body, intramandibular fat body and the melon . The melon consists of fat, and the skull of any such creature containing a melon will have a large depression. The melon size varies between species, the bigger it is, the more dependent they are on it. A beaked whale, for example, has

11600-640: The dorsal fin and across the back. Males and females also have different patterns of black and white skin in their genital areas. In newborns, the white areas are yellow or orange coloured. Antarctic orcas may have pale grey to nearly white backs. Some Antarctic orcas are brown and yellow due to diatoms in the water. Both albino and melanistic orcas have been documented. Orca pectoral fins are large and rounded, resembling paddles, with those of males significantly larger than those of females. Dorsal fins also exhibit sexual dimorphism , with those of males about 1.8 m (5 ft 11 in) high, more than twice

11745-491: The dorsal fin and the pattern of white or grey in the saddle patch are unique. Published directories contain identifying photographs and names for hundreds of North Pacific animals. Photographic identification has enabled the local population of orcas to be counted each year rather than estimated, and has enabled great insight into life cycles and social structures. Orcas are found in all oceans and most seas. Due to their enormous range , numbers, and density, relative distribution

11890-524: The effect. A 2017 study by scientists from Germany 's University of Kiel suggests that large geomagnetic disruptions of the Earth's magnetic field , brought on through solar storms , could be another cause for whale beachings. The authors hypothesize that whales navigate using the Earth's magnetic field by detecting differences in the field's strength to find their way. The solar storms cause anomalies in

12035-526: The elevation of Eastern North American resident and transient orcas as distinct species, O. ater and O. rectipinnus respectively. The Society for Marine Mammalogy declined to recognize the two species, citing uncertainty as to whether the types constituted unique species or subspecies. "Pending a more complete global review and revision", the Society provisionally recognized them as subspecies Orcinus orca ater and O. o. rectipinnus , with O. o. orca as

12180-409: The exception sperm whales), and eyes placed on the sides of their heads. Toothed whales range in size from the 4.5 ft (1.4 m) and 120 lb (54 kg) vaquita to the 20 m (66 ft) and 55 t (61-short-ton) sperm whale. Overall, they tend to be dwarfed by their relatives, the baleen whales (Mysticeti). Several species have sexual dimorphism, with the females being larger than

12325-641: The field, which may disturb the whales' ability to navigate, sending them into shallow waters where they get trapped. The study is based on the mass beachings of 29 sperm whales along the coasts of Germany, the Netherlands , the UK and France in 2016. Some strandings may be caused by larger cetaceans following dolphins and porpoises into shallow coastal waters. The larger animals may habituate to following faster-moving dolphins. If they encounter an adverse combination of tidal flow and seabed topography ,

12470-475: The front, and a tail fin. These flippers contain four digits. Although toothed whales do not possess fully developed hind limbs, some, such as the sperm whale, possess discrete rudimentary appendages, which may contain feet and digits. Toothed whales are fast swimmers in comparison to seals, which typically cruise at 5–15 knots, or 9–28 km/h (5.6–17.4 mph); the sperm whale, in comparison, can travel at speeds of up to 35 km/h (22 mph). The fusing of

12615-484: The harsh climate. Calves are born with only a thin layer of blubber, but some species compensate for this with thick lanugos . Toothed whales have also evolved the ability to store large amounts of wax esters in their adipose tissue as an addition to or in complete replacement of other fats in their blubber. They can produce isovaleric acid from branched chain fatty acids (BCFA). These adaptations are unique, are only in more recent, derived lineages and were likely part of

12760-551: The head, through which this kind fish takes its breath and spitting water, located in front of the brain and ends outwardly in a simple hole, but inside it is divided by a downward bony septum, as if it were two nostrils; but underneath it opens up again in the mouth in a void. –John Ray, 1671, the earliest description of cetacean airways In Aristotle 's time, the fourth century BC, whales were regarded as fish due to their superficial similarity. Aristotle, however, could already see many physiological and anatomical similarities with

12905-412: The high diversity of prey. On average, an orca eats 227 kilograms (500 lb) each day. While salmon are usually hunted by an individual whale or a small group, herring are often caught using carousel feeding : the orcas force the herring into a tight ball by releasing bursts of bubbles or flashing their white undersides. They then slap the ball with their tail flukes, stunning or killing up to 15 fish at

13050-522: The humans are trying to reach, or suddenly start to toss around a chunk of ice after a human throws a snowball. The orca's use of dialects and the passing of other learned behaviours from generation to generation have been described as a form of animal culture . The complex and stable vocal and behavioural cultures of sympatric groups of killer whales ( Orcinus orca ) appear to have no parallel outside humans and represent an independent evolution of cultural faculties. Female orcas begin to mature at around

13195-406: The inner ear. The ear is acoustically isolated from the skull by air-filled sinus pockets, which allow for greater directional hearing underwater. Odontocetes generate sounds independently of respiration using recycled air that passes through air sacs and phonic (alternatively monkey) lips. Integral to the lips are oil-filled organs called dorsal bursae that have been suggested to be homologous in

13340-900: The large squid. A 2010 study suggests that female sperm whales may collaborate when hunting Humboldt squid . The orca is known to prey on numerous other toothed whale species. One example is the false killer whale . To subdue and kill whales, orcas continually ram them with their heads; this can sometimes kill bowhead whales , or severely injure them. Other times, they corral their prey before striking. They are typically hunted by groups of 10 or fewer orca, but they are seldom attacked by an individual. Calves are more commonly taken by orca, but adults can be targeted, as well. Groups even attack larger cetaceans such as minke whales , gray whales , and rarely sperm whales or blue whales . Other marine mammal prey species include nearly 20 species of seal , sea lion and fur seal . These cetaceans are targeted by terrestrial and pagophilic predators. The polar bear

13485-445: The larger species may become trapped. Sometimes following a dolphin can help lead a whale out of danger: In 2008, a local dolphin was followed out to open water by two pygmy sperm whales that had become lost behind a sandbar at Mahia Beach , New Zealand. Pods of killer whales – predators of dolphins and porpoises – very rarely strand. It might be that killer whales have learned to stay away from shallow waters, and that heading to

13630-598: The liver of sharks. In one case a single orca was observed killing and eating a great white shark on its own. Orcas are sophisticated and effective predators of marine mammals . They are recorded to prey on other cetacean species, usually smaller dolphins and porpoises such as common dolphins , bottlenose dolphins , Pacific white-sided dolphins , dusky dolphins , harbour porpoises and Dall's porpoises . While hunting these species, orcas usually have to chase them to exhaustion. For highly social species, orca pods try to separate an individual from its group. Larger groups have

13775-465: The lungs meets cold air, so it does not form in warmer climates, as with river dolphins. Almost all cetaceans have a thick layer of blubber , except for river dolphins. In species that live near the poles, the blubber can be as thick as 11 in (28 cm). This blubber can help with buoyancy, protection to some extent as predators would have a hard time getting through a thick layer of fat, energy for fasting during leaner times, and insulation from

13920-423: The males. One exception is with the sperm whale, which has males larger than the females. Odontocetes possess teeth with cementum cells overlying dentine cells. Unlike human teeth, which are composed mostly of enamel on the portion of the tooth outside of the gum, whale teeth have cementum outside the gum. Only in larger whales, where the cementum is worn away on the tip of the tooth, does enamel show. There

14065-431: The melon-shaped forehead, reflected off objects, and retrieved through the lower jaw. Skulls of Squalodon show evidence for the first hypothesized appearance of echolocation. Squalodon lived from the early to middle Oligocene to the middle Miocene , around 33-14 mya. Squalodon featured several commonalities with modern Odontocetes. The cranium was well compressed, the rostrum telescoped outward (a characteristic of

14210-528: The military to detect submarines is the loudest sound ever put into the seas. Yet the U.S. Navy is planning to deploy LFA sonar across 80 percent of the world ocean. At an amplitude of two hundred forty decibels, it is loud enough to kill whales and dolphins and has already caused mass strandings and deaths in areas where U.S. and/or NATO forces have conducted exercises. The large and rapid pressure changes made by loud sonar can cause hemorrhaging . Evidence emerged after 17 cetaceans were hauled out in

14355-403: The mirror test. Dolphins make a broad range of sounds using nasal airsacs located just below the blowhole. Roughly three categories of sounds can be identified: frequency modulated whistles, burst-pulsed sounds and clicks. Dolphins communicate with whistle-like sounds produced by vibrating connective tissue, similar to the way human vocal cords function, and through burst-pulsed sounds, though

14500-462: The modern parvorder Odontoceti ), giving Squalodon an appearance similar to that of modern toothed whales. However, it is thought unlikely that squalodontids are direct ancestors of living dolphins. Toothed whales have torpedo-shaped bodies with usually inflexible necks, limbs modified into flippers, no outer ears, a large tail fin, and bulbous heads (with the exception of the sperm whale family ). Their skulls have small eye orbits, long beaks (with

14645-638: The most susceptible. This includes the sperm whale , oceanic dolphins, usually pilot and Orcas , and a few beaked whale species. The most common species to strand in the United Kingdom is the harbour porpoise ; the common dolphin ( Delphinus delphis ) is second-most common, and after that long-finned pilot whales ( Globicephala melas ). Solitary species naturally do not strand en masse. Cetaceans that spend most of their time in shallow, coastal waters almost never mass strand. Strandings can be grouped into several types. The most obvious distinction

14790-420: The mouth is closed. The firm middle and back teeth hold prey in place, while the front teeth are inclined slightly forward and outward to protect them from powerful jerking movements. Orcas have good eyesight above and below the water, excellent hearing, and a good sense of touch. They have exceptionally sophisticated echolocation abilities, detecting the location and characteristics of prey and other objects in

14935-403: The nature and extent of that ability is not known. The clicks are directional and are for echolocation, often occurring in a short series called a click train. The click rate increases when approaching an object of interest. Dolphin echolocation clicks are amongst the loudest sounds made by marine animals. Bottlenose dolphins have been found to have signature whistles, a whistle that is unique to

15080-536: The neck vertebrae, while increasing stability when swimming at high speeds, decreases flexibility, rendering them incapable of turning their heads; river dolphins, however, have unfused neck vertebrae and can turn their heads. When swimming, toothed whales rely on their tail fins to propel them through the water. Flipper movement is continuous. They swim by moving their tail fin and lower body up and down, propelling themselves through vertical movement, while their flippers are mainly used for steering. Some species log out of

15225-416: The newborn, toothed whales, being aquatic, must squirt the milk into the mouth of the calf. Being mammals, they have mammary glands used for nursing calves; they are weaned around 11 months of age. This milk contains high amounts of fat which is meant to hasten the development of blubber; it contains so much fat, it has the consistency of toothpaste. Females deliver a single calf, with gestation lasting about

15370-604: The next, evidenced by older individuals nudging juveniles towards the shore, and can sometimes also be a play activity. There is evidence that active sonar leads to beaching. On some occasions cetaceans have stranded shortly after military sonar was active in the area, suggesting a link. Theories describing how sonar may cause whale deaths have also been advanced after necropsies found internal injuries in stranded cetaceans. In contrast, some who strand themselves due to seemingly natural causes are usually healthy prior to beaching: The low frequency active sonar (LFA sonar) used by

15515-534: The northeast Atlantic around the Norwegian coast, in the north Pacific along the Aleutian Islands , the Gulf of Alaska and in the Southern Ocean off much of the coast of Antarctica . They are considered "common" (0.20–0.40 individuals per 100 km) in the eastern Pacific along the coasts of British Columbia , Washington and Oregon , in the North Atlantic Ocean around Iceland and

15660-809: The northwest Atlantic. Occasionally, orcas swim into freshwater rivers. They have been documented 100 mi (160 km) up the Columbia River in the United States. They have also been found in the Fraser River in Canada and the Horikawa River in Japan. Migration patterns are poorly understood. Each summer, the same individuals appear off the coasts of British Columbia and Washington. Despite decades of research, where these animals go for

15805-416: The operating area of Neo Tapon, an international naval exercise, about four hours after the activation of mid-frequency sonar. The team of scientists found acute tissue damage from gas-bubble lesions, which are indicative of decompression sickness. The precise mechanism of how sonar causes bubble formation is not known. It could be due to cetaceans panicking and surfacing too rapidly in an attempt to escape

15950-451: The orca's conservation status as data deficient because of the likelihood that two or more orca types are separate species . Some local populations are considered threatened or endangered due to prey depletion, habitat loss , pollution (by PCBs ), capture for marine mammal parks , and conflicts with human fisheries . In late 2005, the southern resident orcas were placed on the U.S. Endangered Species list . Orcas are not usually

16095-536: The original sound. In larger groups, individual whistle sounds are less prominent. Dolphins tend to travel in pods, sometimes of up to 600 members. Cetaceans are known to communicate and therefore are able to teach, learn, cooperate, scheme, and grieve. The neocortex of many species of dolphins is home to elongated spindle neurons that, prior to 2007, were known only in hominids. In humans, these cells are involved in social conduct, emotions, judgement, and theory of mind. Dolphin spindle neurons are found in areas of

16240-662: The porpoise as a fish.   Sperm whales (Physeteridae) [REDACTED]   Dwarf sperm whales (Kogiidae) [REDACTED]   South Asian river dolphins (Platanistidae) [REDACTED]   Beaked whales (Ziphiidae) [REDACTED]   Yangtze river dolphin (Lipotidae) [REDACTED]   Pontoporiidae [REDACTED]   Iniidae [REDACTED]   Oceanic dolphins (Delphinidae) [REDACTED]   Porpoises  (Phocoenidae) [REDACTED]   Belugas , narwhals (Monodontidae) [REDACTED] Toothed whales, as well as baleen whales, are descendants of land-dwelling mammals of

16385-494: The powerful sonar pulses resonated with airspaces in the dolphins, tearing tissue around the ears and brain. Apparently not all species are affected by sonar. Another means by which sonar could be hurting cetaceans is a form of decompression sickness . This was first raised by necrological examinations of 14  beaked whales stranded in the Canary Islands . The stranding happened on 24 September 2002, close to

16530-438: The range of infrasonic frequencies. Bottlenose dolphins have been found to have signature whistles unique to each individual. Dolphins use these whistles to communicate with one another by identifying an individual. It can be seen as the dolphin equivalent of a name for humans. Because dolphins generally live in groups, communication is necessary. Signal masking is when other similar sounds (conspecific sounds) interfere with

16675-417: The rest of the year remains unknown. Transient pods have been sighted from southern Alaska to central California. Worldwide population estimates are uncertain, but recent consensus suggests a minimum of 50,000 (2006). Local estimates include roughly 25,000 in the Antarctic, 8,500 in the tropical Pacific, 2,250–2,700 off the cooler northeast Pacific and 500–1,500 off Norway. Japan's Fisheries Agency estimated in

16820-487: The sea by a combination of their own impetus and retreating water, and have to wait for the next wave to re-float them and carry them back to sea. In Argentina, killer whales are known to hunt on the shore by intentionally beaching themselves and then lunging at nearby seals before riding the next wave safely back into deeper waters. This was first observed in the early 1970s, then hundreds times more since within this pod. This behavior seems to be taught from one generation to

16965-518: The second-heaviest brains among marine mammals (after sperm whales , which have the largest brain of any animal). Orcas have more gray matter and more cortical neurons than any mammal, including humans. They can be trained in captivity and are often described as intelligent, although defining and measuring "intelligence" is difficult in a species whose environment and behavioural strategies are very different from those of humans. Orcas imitate others, and seem to deliberately teach skills to their kin. Off

17110-581: The shallows offers the smaller animals some protection from predators. However, killer whales in Península Valdés , Argentina, and the Crozet Islands in the Indian Ocean have learned how to operate in shallow waters, particularly in their pursuit of seals. The killer whales regularly demonstrate their competence by chasing seals up shelving gravel beaches, up to the edge of the water. The pursuing whales are occasionally partially thrust out of

17255-478: The shore, making them difficult to study in the wild. Prior to the interest raised by the sonar controversy, most of the information about them came from stranded animals. The first to publish research linking beachings with naval activity were Simmonds and Lopez-Jurado in 1991. They noted that over the past decade there had been a number of mass strandings of beaked whales in the Canary Islands, and each time

17400-418: The sides of the head, so their vision consists of two fields, rather than a binocular view as humans have. When a beluga surfaces, its lenses and corneas correct the nearsightedness that results from the refraction of light; they contain both rod and cone cells, meaning they can see in both dim and bright light. They do, however, lack short wavelength-sensitive visual pigments in their cone cells, indicating

17545-418: The size of the female's, with the male's fin more like an elongated isosceles triangle , whereas the female's is more curved. In the skull, adult males have longer lower jaws than females, as well as larger occipital crests . The snout is blunt and lacks the beak of other species. The orca's teeth are very strong, and its jaws exert a powerful grip; the upper teeth fall into the gaps between the lower teeth when

17690-449: The slope is about half a degree (approximately 8 m [26 ft] deep one km [0.62 mi] out to sea). The University of Western Australia Bioacoustics group proposes that repeated reflections between the surface and ocean bottom in gently sloping shallow water may attenuate sound so much that the echo is inaudible to the whales. Stirred up sand as well as long-lived microbubbles formed by rain may further exacerbate

17835-475: The smaller species of dolphins, only a few of the larger sharks, such as the bull shark , dusky shark , tiger shark , and great white shark , are a potential risk, especially for calves. Dolphins can tolerate and recover from extreme injuries (including shark bites) although the exact methods used to achieve this are not known. The healing process is rapid and even very deep wounds do not cause dolphins to hemorrhage to death. Even gaping wounds restore in such

17980-423: The snout may correlate with tooth number and thus feeding mechanisms. The narwhal, with its blunt snout and reduced dentition, relies on suction feeding . Sperm whales usually dive between 300 and 800 metres (980 and 2,620 ft), and sometimes 1 to 2 kilometres (3,300 to 6,600 ft), in search of food. Such dives can last more than an hour. They feed on several species, notably the giant squid , but also

18125-811: The snubfin dolphins of the genus Orcaella . However, a more recent (2018) study places the orca as a sister taxon to the Lissodelphininae, a clade that includes Lagenorhynchus and Cephalorhynchus . In contrast, a 2019 phylogenetic study found the orca to be the second most basal member of the Delphinidae, with only the Atlantic white-sided dolphin ( Leucopleurus acutus ) being more basal. The three to five types of orcas may be distinct enough to be considered different races , subspecies , or possibly even species (see Species problem ). The IUCN reported in 2008, "The taxonomy of this genus

18270-478: The sonar pulses. There is also a theoretical basis by which sonar vibrations can cause supersaturated gas to nucleate , forming bubbles, which are responsible for decompression sickness. The overwhelming majority of the cetaceans involved in sonar-associated beachings are Cuvier's beaked whales ( Ziphius cavirostrus ). Individuals of this species strand frequently, but mass strandings are rare. Cuvier's beaked whales are an open-ocean species that rarely approach

18415-404: The sound of exploding harpoons indicating the availability of prey to scavenge, and compressed air inflation of whale carcasses causing them to float, thus exposing them to scavenging. However, the devastation of great whale populations by unfettered whaling has possibly reduced their availability for orcas, and caused them to expand their consumption of smaller marine mammals, thus contributing to

18560-403: The south coast of Western Australia, including an estimated 18–22-meter (59–72 ft) individual. Large whales require much effort and coordination to kill and orcas often target calves. A hunt begins with a chase followed by a violent attack on the exhausted prey. Large whales often show signs of orca attack via tooth rake marks. Pods of female sperm whales sometimes protect themselves by forming

18705-461: The strength of response of individual animals may depend on whether they had prior exposure to sonar, and that symptoms of decompression sickness have been found in stranded whales that may be a result of such response to sonar. It noted that no more mass strandings had occurred in the Canary Islands once naval exercises where sonar was used were banned, and recommended that the ban be extended to other areas where mass strandings continue to occur. If

18850-472: The surface and strike them with their tail flukes, while bottom-dwelling rays are cornered, pinned to the ground and taken to the surface. In other parts of the world, orcas have preyed on broadnose sevengill sharks , small whale sharks and even great white sharks . Competition between orcas and white sharks is probable in regions where their diets overlap. The arrival of orcas in an area can cause white sharks to flee and forage elsewhere. Orcas appear to target

18995-461: The surface as sperm whales do. Every deep dive is followed by three or four shallow dives. The elaborate dive patterns are assumed to be necessary to control the diffusion of gases in the bloodstream. No data show a beaked whale making an uncontrolled ascent, or failing to do successive shallow dives. This behavior suggests that the Cuvier's are in a vulnerable state after a deep dive – presumably on

19140-457: The surface, attracting sea gulls, and then eat the birds. Four others then learned to copy the behaviour. Day-to-day orca behaviour generally consists of foraging , travelling, resting and socializing. Orcas frequently engage in surface behaviour such as breaching (jumping completely out of the water) and tail-slapping. These activities may have a variety of purposes, such as courtship, communication, dislodging parasites , or play . Spyhopping

19285-480: The surrounding environment, but are also commonly heard during social interactions. Northeast Pacific resident groups tend to be much more vocal than transient groups in the same waters. Residents feed primarily on Chinook and chum salmon, which are insensitive to orca calls (inferred from the audiogram of Atlantic salmon). In contrast, the marine mammal prey of transients hear whale calls well and thus transients are typically silent. Vocal behaviour in these whales

19430-501: The teeth are seen to erupt in the lower jaw, and primarily occurs at the males sexual maturity. Not all species are believed to use their teeth for feeding. For instance, the sperm whale likely uses its teeth for aggression and showmanship. Breathing involves expelling stale air from their one blowhole , forming an upward, steamy spout, followed by inhaling fresh air into the lungs. Spout shapes differ among species, which facilitates identification. The spout only forms when warm air from

19575-523: The terrestrial vertebrates, such as blood (circulation), lungs, uterus, and fin anatomy. His detailed descriptions were assimilated by the Romans, but mixed with a more accurate knowledge of the dolphins, as mentioned by Pliny the Elder in his Natural history . In the art of this and subsequent periods, dolphins are portrayed with a high-arched head (typical of porpoises) and a long snout. The harbor porpoise

19720-542: The time), both near the surface and at depth, which suggests they are primarily mating signals. Outside breeding grounds, slow clicks are rarely heard, and usually near the surface. All whales are carnivorous and predatory . Odontocetes, as a whole, mostly feed on fish and cephalopods , and then followed by crustaceans and bivalves . All species are generalist and opportunistic feeders. Some may forage with other kinds of animals, such as other species of whales or certain species of pinnipeds . One common feeding method

19865-443: The time, it was noted as "atypical" both because mass strandings of beaked whales are rare, and also because the stranded whales were spread over such a long stretch of coast, with each individual whale spatially separated from the next stranding. At the time of the incident, there was no connection made with active sonar; A. Frantzis, the marine biologist investigating the incident, made the connection to sonar because he discovered

20010-425: The toothed whale lineage. Modern toothed whales do not rely on their sense of sight, but rather on their sonar to hunt prey. Echolocation also allowed toothed whales to dive deeper in search of food, with light no longer necessary for navigation, which opened up new food sources. Toothed whales (Odontocetes) echolocate by creating a series of clicks emitted at various frequencies. Sound pulses are emitted through

20155-449: The transition for species to become deeper divers as the families of toothed whales (Physeteridae, Kogiidae, and Ziphiidae) that have the highest quantities of wax esters and BCFAs in their blubber are also the species that dive the deepest and for the longest amount of time. Toothed whales have a two-chambered stomach similar in structure to terrestrial carnivores. They have fundic and pyloric chambers. Cetaceans have two flippers on

20300-439: The two-thirds or three-quarters exponent of the body mass. Comparison of a particular animal's brain size with the expected brain size based on such allometric analysis provides an encephalization quotient that can be used as another indication of animal intelligence. Sperm whales have the largest brain mass of any animal on earth, averaging 8,000 cm (490 in ) and 7.8 kg (17 lb) in mature males, in comparison to

20445-418: The verge of decompression sickness – and require time and perhaps the shallower dives to recover. De Quirós et al. (2019) published a review of evidence on the mass strandings of beaked whale linked to naval exercises where sonar was used. It concluded that the effects of mid-frequency active sonar are strongest on Cuvier's beaked whales but vary among individuals or populations. The review suggested

20590-572: The water by emitting clicks and listening for echoes, as do other members of the dolphin family. The mean body temperature of the orca is 36 to 38 °C (97 to 100 °F). Like most marine mammals, orcas have a layer of insulating blubber ranging from 7.6 to 10 cm (3.0 to 3.9 in) thick beneath the skin. The pulse is about 60 heartbeats per minute when the orca is at the surface, dropping to 30 beats/min when submerged. An individual orca can often be identified from its dorsal fin and saddle patch. Variations such as nicks, scratches, and tears on

20735-504: The water, which may allow them to travel faster. Their skeletal anatomy allows them to be fast swimmers. Most species have a dorsal fin . Most toothed whales are adapted for diving to great depths, porpoises are one exception. In addition to their streamlined bodies, they can slow their heart rate to conserve oxygen; blood is rerouted from tissue tolerant of water pressure to the heart and brain among other organs; haemoglobin and myoglobin store oxygen in body tissue; and they have twice

20880-614: Was due to a change in the climate of the southern oceans that affected where the environment of the plankton that these whales ate. The adaptation of echolocation and enhanced fat synthesis in blubber occurred when toothed whales split apart from baleen whales, and distinguishes modern toothed whales from fully aquatic archaeocetes. This happened around 34 mya. Unlike toothed whales, baleen whales do not have wax ester deposits nor branched fatty chain acids in their blubber. Thus, more recent evolution of these complex blubber traits occurred after baleen whales and toothed whales split, and only in

21025-404: Was estimated by some researchers to have been as old as 105 years at the time of her death, though a biopsy sample indicated her age as 65 to 80 years. It is thought that orcas held in captivity tend to have shorter lives than those in the wild, although this is subject to scientific debate. Toothed whale The toothed whales (also called odontocetes , systematic name Odontoceti ) are

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