A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance , out of a specific population or collection. Systematic names are usually part of a nomenclature .
76-529: The toothed whales (also called odontocetes , systematic name Odontoceti ) are 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
152-465: A unique identifier . Systematic names often co-exist with earlier common names assigned before the creation of any systematic naming system. For example, many common chemicals are still referred to by their common or trivial names, even by chemists. In chemistry, a systematic name describes the chemical structure of a chemical substance , thus giving some information about its chemical properties. The Compendium of Chemical Terminology published by
228-424: 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,
304-443: 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 ,
380-439: 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
456-437: A human fingerprint; no one animal's appearance exactly like another's. Once Biggs and Ellis found they could recognize certain individuals, they realised that the animals travel in stable groups called pods. Researchers use photo identification to identify specific individuals and pods. The photographic system has also worked well in humpback whale studies. Researchers use the color of the pectoral fins and color and scarring of
532-423: 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
608-430: 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"
684-459: 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
760-408: 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,
836-432: 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
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#1732775282961912-563: 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
988-539: 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
1064-575: 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,
1140-451: 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
1216-428: 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. Systematic name A semisystematic name or semitrivial name
1292-455: Is a name that has at least one systematic part and at least one trivial part, such as a chemical vernacular name . Creating systematic names can be as simple as assigning a prefix or a number to each object (in which case they are a type of numbering scheme ), or as complex as encoding the complete structure of the object in the name. Many systems combine some information about the named object with an extra sequence number to make it into
1368-406: 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
1444-474: 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
1520-436: 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
1596-411: 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
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#17327752829611672-447: 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
1748-499: Is photo-identification. This system was popularized by Michael Bigg , a pioneer in modern orca (killer whale) research. During the mid-1970s, Bigg and Graeme Ellis photographed local orcas in the British Columbian seas. After examining the photos, they realized they could recognize certain individual whales by looking at the shape and condition of the dorsal fin, and also the shape of the saddle patch. These are as unique as
1824-399: 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
1900-474: Is the branch of marine mammal science that studies the approximately eighty species of whales , dolphins , and porpoises in the scientific order Cetacea . Cetologists, or those who practice cetology, seek to understand and explain cetacean evolution , distribution, morphology , behavior, community dynamics, and other topics. Observations about Cetacea have been recorded since at least classical times. Ancient Greek fishermen created an artificial notch on
1976-409: Is through examination of dead carcasses that wash up on the shore. If properly collected and stored, these carcasses can provide important information that is difficult to obtain in field studies. In recent decades, methods of identifying individual cetaceans have enabled accurate population counts and insights into the life cycles and social structures of various species. One such successful system
2052-399: 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
2128-464: 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
2204-518: 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
2280-692: The IUPAC defines systematic name as "a name composed wholly of specially coined or selected syllables, with or without numerical prefixes; e.g. pentane, oxazole." However, when trivial names have become part of chemical nomenclature , they can be the systematic name of a substance or part of it. Examples for some systematic names that have trivial origins are benzene (cyclohexatriene) or glycerol (trihydroxypropane). There are standardized systematic or semi-systematic names for: Cetology Cetology (from Greek κῆτος , kētos , " whale "; and -λογία , -logia ) or whalelore (also known as whaleology )
2356-399: 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
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2432-608: 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
2508-470: The dung of whales often floats and can be collected to tell important information about their diet and about the role they have in the environment. Often cetology involves waiting and paying close attention. Cetologists use equipment including hydrophones to listen to calls of communicating animals, binoculars and other optical devices for scanning the horizon, cameras, notes, and a few other devices and tools. An alternative method of studying cetaceans
2584-437: The medieval texts on cetaceans come mainly from Scandinavia and Iceland, most came about the mid-13th century. One of the better known is Speculum Regale . This text describes various species that lived around the island of Iceland . It mentions orcs that had dog-like teeth and would demonstrate the same kind of aggression towards other cetaceans as wild dogs would to other terrestrial animals . The text even illustrated
2660-413: 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
2736-459: The sperm whale and the common dolphin , stating that they can live for at least twenty-five or thirty years. His achievement was remarkable for its time, because even today it is very difficult to estimate the life-span of advanced marine animals. After Aristotle's death, much of the knowledge he had gained about cetaceans was lost, only to be re-discovered during the Renaissance . Many of
2812-528: 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
2888-569: The Elder stated that they were fish, and it was followed by many naturalists . However, Pierre Belon (1517–1575) and G. Rondelet (1507–1566) persisted on believing they were mammals. They argued that the animals had lungs and a uterus , just like mammals. Not until 1758, when Swedish botanist Carl Linnaeus (1707–1778) published the tenth edition of Systema Naturae , were they seen as mammals. Only decades later, French zoologist and paleontologist Baron Georges Cuvier (1769–1832) described
2964-421: The animals as mammals without any hind legs. Skeletons were assembled and displayed in the first natural history museums , and on a closer look and comparisons with other extinct animal fossils, led zoologists to conclude that cetaceans came from a family of ancient land mammals. Between the 16th and 20th centuries, much of our information on cetaceans came from whalers . Whalers were the most knowledgeable about
3040-464: The animals, but their information was regarding migration routes and outer anatomy, and only little information of behavior. During the 1960s, people began studying the animals intensively, often in dedicated research institutes. The Tethys Institute of Milan, founded in 1986, compiled an extensive cetology database of the Mediterranean. This came from both concern about wild populations and also
3116-430: 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
Toothed whale - Misplaced Pages Continue
3192-449: 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
3268-444: The capture of larger animals such as the orca, and gaining popularity of dolphin shows in marine parks . Studying cetaceans presents numerous challenges. Cetaceans only spend 10% of their time on the surface, and all they do at the surface is breathe. There is very little behavior seen at the surface. It is also impossible to find any signs that an animal has been in an area. Cetaceans do not leave tracks that can be followed. However,
3344-411: 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 the sides of
3420-440: 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
3496-504: The dorsal fin of dolphins entangled in nets so that they could tell them apart years later. Approximately 2,300 years ago, Aristotle carefully took notes on cetaceans while traveling on boats with fishermen in the Aegean Sea . In his book Historia animalium ( History of Animals ), Aristotle was careful enough to distinguish between the baleen whales and toothed whales , a taxonomical separation still used today. He also described
3572-409: 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
3648-474: 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
3724-482: 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
3800-405: 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
3876-551: 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
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#17327752829613952-460: The hunting technique of orcs , which are now called orcas. The Speculum Regale describes other cetaceans, including the sperm whale and narwhal . Many times they were seen as terrible monsters, such as killers of men, and destroyers of ships. They even bore odd names such as "pig whale", "horse whale", and "red whale". But not all creatures described were said to be fierce. Some were seen to be good, such as whales that drove shoals of herring towards
4028-404: 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
4104-894: 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
4180-462: 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
4256-420: 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
4332-430: 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
4408-401: 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
4484-461: 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
4560-402: 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
4636-536: 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
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#17327752829614712-415: 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
4788-532: 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
4864-660: 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
4940-436: 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
5016-538: The shore. This was seen as very helpful to fisherman. Many of the early studies were based on dead specimens and myth . The little information that was gathered was usually about length, and a rough outer body anatomy . Because these animals live in water their entire lives, early scientists did not have the technology to study these animals further. It was not until the 16th century that things would begin to change. Then cetaceans would be proved to be mammals rather than fish. Aristotle argued they were mammals. But Pliny
5092-474: 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
5168-418: 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
5244-499: 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
5320-470: 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
5396-538: 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
5472-420: 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
5548-447: 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
5624-437: 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
5700-501: 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
5776-612: 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
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