mgsv whale | i speak whale dory
Whales are descendants of land-dwelling mammals of the artiodactyl order (even-toed ungulates). They are relevant to the Indohyus, an extinct chevrotain-like ungulate, from which they split approximately 48 , 000, 000 years ago.|19||20| Primitive cetaceans, or archaeocetes, first took to the sea about 49 million years ago to become fully aquatic 5-10 million years later. What defines an archaeocete is the existence of anatomical features unique to cetaceans, alongside different primitive features not found in modern cetaceans, such as noticeable legs or asymmetrical teeth.|21||22||23||9| Their features started to be adapted for living in the marine environment. Major anatomical changes included their hearing set-up that channeled heurt from the jaw to the earbone (Ambulocetus 49 mya), a streamlined body and the regarding flukes on the tail (Protocetus 43 mya), the migration of the nostrils toward the best of the cranium (blowholes), as well as the modification of the forelimbs in to flippers (Basilosaurus 35 mya), and the shrinking and later disappearance of the hind arms and legs (the first odontocetes and mysticetes 34 mya).|24||25||26|
Whale morphology shows a number of examples of concourant evolution, the most obvious being the streamlined fish-like body shape.|27| Other examples include the utilization of echolocation for hunting in low light conditions - which can be the same hearing adaptation employed by bats - and, inside the rorqual whales, jaw adaptations, similar to those found in pelicans, that enable engulfment feeding.|28|
Today, the closest living relatives of cetaceans are the hippopotamuses; these show a semi-aquatic ancestor that branched off from other artiodactyls some 60 mya.|9| Around 40 mya, a common ancestor between the two branched off into cetacea and anthracotheres; nearly all anthracotheres became extinct at the end of the Pleistocene 2 . 5 mya, eventually leaving only one living lineage - the hippopotamus.|29|
Whales split into two separate parvorders around 34 mya - the baleen whales (Mysticetes) and the toothed whales (Odontocetes).
Whales have torpedo shaped physiques with non-flexible necks, limbs modified into flippers, non-existent external ear flaps, a big tail fin, and level heads (with the exclusion of monodontids and ziphiids). Whale skulls have tiny eye orbits, long snouts (with the exception of monodontids and ziphiids) and eyes placed on the attributes of its head. Whales range in size from the 2 . 6-metre (8. 5 ft) and 135-kilogram (298 lb) dwarf sperm whale for the 34-metre (112 ft) and 190-metric-ton (210-short-ton) blue whale. Overall, they tend to dwarf other cetartiodactyls; the rare whale is the largest person on earth. Several species have got female-biased sexual dimorphism, with all the females being larger than the males. One exception is by using the sperm whale, that has males larger than the females.|33||34|
Odontocetes, such as the sperm whale, possess tooth with cementum cells overlying dentine cells. Unlike individuals teeth, which are composed mostly of enamel on the component of the tooth outside of the gum, whale teeth include cementum outside the gum. Just in larger whales, where the cementum is worn aside on the tip of the tooth, does enamel show. Mysticetes have large whalebone, instead of teeth, made of keratin. Mysticetes have two blowholes, although Odontocetes contain only one.|35|
Breathing involves expelling stale air from the blowhole, forming an upward, steamy spout, followed by inhaling fresh air into the lungs; a humpback whale's lungs can hold about 5, 000 litres of air. Spout shapes differ among species, which facilitates recognition.|36||37|
The center of a whale weighs about 180-200 kg. It is 640 times bigger than a human heart. The heart of the green whale is the largest of any animal,|38| and the walls of the arteries in the heart have been described as being "as thick while an iPhone 6 Plus is definitely long".|39|
All whales have a thick level of blubber. In varieties that live near the poles, the blubber can be as thick because 11 inches. This blubber can help with buoyancy (which is helpful for a 100-ton whale), protection to some extent as predators might have a hard time getting through a thick layer of fat, and energy for fasting once migrating to the equator; the main usage for blubber is usually insulation from the harsh weather conditions. It can constitute as much as 50 percent of a whale's body weight. Calf muscles are born with just a thin layer of blubber, sometimes species compensate for this with thick lanugos.|40||41|
Whales have a two- to three-chambered stomach that is certainly similar in structure to terrestrial carnivores. Mysticetes contain a proventriculus as an extension from the oesophagus; this contains gallstones that grind up food. They also have fundic and pyloric chambers.
Whales have two flippers for the front, and a tail fin. These flippers consist of four digits. Although whales do not possess fully developed hind limbs, some, such as the ejaculate whale and bowhead whale, possess discrete rudimentary appendages, which may contain feet and digits. Whales are fast swimmers in comparison to seals, which usually typically cruise at 5-15 kn, or 9-28 kilometres per hour (5. 6-17. four mph); the fin whale, in comparison, can travel by speeds up to 47 kilometres per hour (29 mph) as well as the sperm whale can reach speeds of 35 kilometres per hour (22 mph). The fusing of the neck backbone, while increasing stability when ever swimming at high speeds, decreases flexibility; whales are unable to turn their heads. When ever swimming, whales rely on the tail fin propel all of them through the water. Flipper activity is continuous. Whales move by moving their tail fin and lower body up and down, propelling themselves through vertical movement, while their particular flippers are mainly used for driving. Some species log out of your water, which may allow them to travel and leisure faster. Their skeletal function allows them to be fast swimmers. Most species have got a dorsal fin.|43||44|
Whales are used for diving to wonderful depths. In addition to their efficient bodies, they can slow their particular heart rate to conserve oxygen; blood vessels is rerouted from cells tolerant of water pressure to the heart and head among other organs; haemoglobin and myoglobin store air in body tissue; and in addition they have twice the concentration of myoglobin than haemoglobin. Before going on long divine, many whales exhibit a behaviour known as sounding; they stay close to the surface for your series of short, shallow dives while building their o2 reserves, and then make a sound dive.
The whale ear has specific adaptations to the marine environment. In humans, the middle ear canal 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, there is no great difference between the outside and inner environments. Instead of sound passing through the outer headsets to the middle ear, whales receive sound through the can range f, from which it passes through a low-impedance fat-filled cavity to the inner ear.|46| The whale ear is usually acoustically isolated from the head by air-filled sinus purses, which allow for greater directional hearing underwater.|47| Odontocetes send out high frequency clicks from an organ known as a melon. This melon consists of fat, and the skull of any such creature containing a melon will have a large depressive disorder. The melon size varies between species, the bigger the more dependent they are of it. A beaked whale for example has a small bulge sitting in addition to its skull, whereas a sperm whale's head is filled up mainly with the memo.|48||49||50||51|
The whale eye is relatively small for its size, yet they do retain a good level of eyesight. As well as this, the eyes of a whale are placed on the sides of it is head, so their perspective consists of two fields, rather than a binocular view like individuals have. When belugas area, their lens and cornea correct the nearsightedness which will result from the refraction of light; that they contain both rod and cone cells, meaning they can see in both dim and bright light, but they include far more rod cells than they do cone cells. Whales do, however , lack short wavelength sensitive visual tones in their cone cells suggesting a more limited capacity for shade vision than most mammals.|52| Most whales have slightly flattened eyeballs, enlarged pupils (which reduce in size as they surface to prevent damage), slightly flattened corneas and a tapetum lucidum; these types of adaptations allow for large amounts of light to pass through the eye and, consequently , a very clear image of surrounding area. They also have glands on the eyelids and outer corneal layer that act as safety for the cornea.|53||54|
The olfactory lobes are absent in toothed whales, suggesting that they have zero sense of smell. Some whales, like the bowhead whale, possess a vomeronasal organ, which does imply that they can "sniff out" krill.|55|
Whales are not considered to have a good sense of taste, as their taste buds will be atrophied or missing totally. However , some toothed whales have preferences between different types of fish, indicating some sort of attachment to taste. The existence of the Jacobson's organ signifies that whales can stink food once inside their oral cavity, which might be similar to the sensation of taste.
2019-02-18 16:41:28 * 2019-02-17 01:02:29
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