Ein Riesenhai, so groß wie ein U-Boot? Das trifft auf den Megalodon zu. Ist er wirklich ausgestorben oder könnte er in den Tiefen des Meeres überlebt haben? Megalodon. Lebt im Marianengraben wirklich noch ein Megalodon? Diese Frage stellen sich viele. Doch eigentlich ist der Koloss schon vor 2,6. Megalodon, der größte Hai aller Zeiten, ist wohl bereits vor 3,6 Millionen Jahren ausgestorben. Sein Verschwinden ist ein Grund, noch mehr.
Urzeithai: Lebt der Riese heute noch in der Tiefsee?Megalodon, der größte Hai aller Zeiten, ist wohl bereits vor 3,6 Millionen Jahren ausgestorben. Sein Verschwinden ist ein Grund, noch mehr. Ein Riesenhai, so groß wie ein U-Boot? Das trifft auf den Megalodon zu. Ist er wirklich ausgestorben oder könnte er in den Tiefen des Meeres überlebt haben? Vom Megalodon haben Menschen nur Fossilien gefunden. Vor allem Zähne, hier zu einem Gebiss planetmut.com: Joe Quinn/Mauritius.
Marianengraben Megalodon Ist der Megalodon noch am Leben? VideoHaben sie einen lebenden Megalodon im Marianengraben gefunden?
Die moderne Wissenschaft behauptet zwar, der blutrünstige Raubfisch wäre seit Langem ausgestorben. Aber stimmt das auch?
Die Vorstellung, dass der Carcharocles Megalodon noch lebt, ist erschreckend und faszinierend zugleich. Ist der Megalodon noch am Leben?
Vereinzelte Berichte über riesige Haie mit einer Länge von über 10 Metern tauchen immer wieder in den Medien auf. Handelt es sich dabei um Megalodon Sichtungen?
Die meisten Haiforscher und Meeresbiologen erklären einhellig, das sei unmöglich. Aber was haben die Augenzeugen dann beobachtet?
Die Vorstellung, dass riesige Raubhaie die Weiten der Ozeane durchstreifen, wirkt elektrisierend. Es ist allerdings schwer vorstellbar, dass es immer noch unentdeckte Populationen dieser furchterregenden Räuber geben soll.
In den letzten Jahren entbrannten viele kontroverse Diskussionen zum Thema Megalodon. Die Geschichten, die sich um ihn ranken, wären nichts weiter als Legenden.
Das ist natürlich Unsinn. Der Megalodon lebte vor 2 bis 17 Millionen Jahren. Anhand des Fossilberichts konnten Wissenschaftler Rückschlüsse auf das Erscheinungsbild des Urzeithais ziehen.
Seine Länge betrug maximal 16 bis 20 Meter bei einem Gewicht von rund 60 Tonnen. Der Megalodon war ein prähistorischer Raubfisch.
Neben dem Megalodon erscheinen diese modernen Haie allerdings eher wie harmlose Haustiere. Als gnadenloser Raubfisch spielte er in einer vollkommen anderen Liga.
Einige der fossilen Zähne sind auch nach Jahrmillionen immer noch rasiermesserscharf. Die beeindruckendsten Funde weisen eine Länge von über 18 Zentimetern auf.
Das Gebiss des Megalodons schätzen Paläontologen auf eine Breite von mehr als drei Metern und eine Höhe von über zweieinhalb Meter. Der Zahn eines Megalodon.
Das Skelett von Haien besteht hauptsächlich aus Knorpel, der nicht versteinern kann. Deshalb sind die einzigen Hinweise auf den prähistorischen Megalodon die fossilen Zahnfunde.
Kein modernes Exemplar des Hais wurde jemals lebend gefangen oder tot geborgen. Darüber hinaus gibt es keine offiziell bestätigten Sichtungen.
Warum glauben viele Menschen trotzdem, dass er noch lebt? Um die Frage beantworten zu können, schauen wir uns einmal an, ob es ein ähnliches Phänomen schon früher gegeben hat.
In der Tat wurde von Wissenschaftlern in manchen Fällen die Existenz eines Lebewesens bestätigt, das zuvor als ausgestorben galt oder für einen Mythos gehalten wurde.
Eindrucksvolle Beispiele dafür sind der Quastenflosser, der Riesenkalmar und der Riesenmaulhai. Die Wissenschaft glaubte lange Zeit, der Quastenflosser wäre vor 65 Millionen Jahren ausgestorben.
Im Jahre geschah dann die Sensation: Ein lebendes Exemplar dieses prähistorischen Fischs wurde vor der Küste Südafrikas entdeckt.
Mit einer Länge von mehr als zwei Metern gilt der Quastenflosser heute als lebendes Fossil. Der Riesenkalmar, der irrtümlich auch als Riesenkrake bezeichnet wird, lebt in der Tiefsee.
Der zehnarmige Tintenfisch erreicht eine Länge von bis zu neun Metern. Seine Existenz war lange Zeit umstritten. Meeresbiologen entdeckten charakteristische Narben an gestrandeten Walen und vermuteten als Ursache einen gigantischen Tintenfisch.
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Vote Now! Photo of the Day. Video Ingenuity Awards. Smithsonian Channel. Unlike the great white, which attacks prey from the soft underside, megalodon probably used its strong jaws to break through the chest cavity and puncture the heart and lungs of its prey.
The animal faced competition from whale-eating cetaceans, such as Livyatan and other macroraptorial sperm whales and possibly smaller ancestral killer whales.
As the shark preferred warmer waters, it is thought that oceanic cooling associated with the onset of the ice ages , coupled with the lowering of sea levels and resulting loss of suitable nursery areas, may have also contributed to its decline.
A reduction in the diversity of baleen whales and a shift in their distribution toward polar regions may have reduced megalodon's primary food source.
The extinction of the shark appeared to affect other animals; for example, the size of baleen whales increased significantly after the shark had disappeared.
According to Renaissance accounts, gigantic triangular fossil teeth often found embedded in rocky formations were once believed to be the petrified tongues, or glossopetrae , of dragons and snakes.
This interpretation was corrected in by Danish naturalist Nicolas Steno , who recognized them as shark teeth , and famously produced a depiction of a shark 's head bearing such teeth.
He described his findings in the book The Head of a Shark Dissected , which also contained an illustration of a megalodon tooth. Swiss naturalist Louis Agassiz gave this shark its initial scientific name , Carcharodon megalodon , in his work Recherches sur les poissons fossiles , based on tooth remains.
English paleontologist Charles Davies Sherborn in listed an series of articles by Agassiz as the first scientific description of the shark.
There was one apparent description of the shark in classifying it as Selache manzonii. While the earliest megalodon remains have been reported from the Late Oligocene , around 28 million years ago mya ,   there is disagreement as to when it appeared, with dates ranging to as young as 16 mya.
Megalodon is now considered to be a member of the family Otodontidae , genus Otodus , as opposed to its previous classification into Lamnidae , genus Carcharodon.
In this model, the great white shark is more closely related to the extinct broad-toothed mako Isurus hastalis than to megalodon, as evidenced by more similar dentition in those two sharks; megalodon teeth have much finer serrations than great white shark teeth.
The great white shark is more closely related to the mako shark Isurus spp. The genus Carcharocles currently contains four species: C.
Jordan and H. Hannibal in to contain C. In the s, megalodon was assigned to Carcharocles. It is now considered a junior synonym of Carcharocles.
It is believed to be an evolutionary dead-end and unrelated to the Carcharocles sharks by authors who reject that model. Another model of the evolution of this genus, also proposed by Casier in , is that the direct ancestor of the Carcharocles is the shark Otodus obliquus , which lived from the Paleocene through the Miocene epochs, 60 mya to 13 mya.
Another model of the evolution of Carcharocles , proposed in by paleontologist Michael Benton , is that the three other species are actually a single species of shark that gradually changed over time between the Paleocene and the Pliocene, making it a chronospecies.
The genus Carcharocles may be invalid, and the shark may actually belong in the genus Otodus , making it Otodus megalodon.
A review of Chondrichthyes elevated Megaselachus to genus, and classified the sharks as Megaselachus megalodon and M. The inclusion of the Carcharocles sharks in Otodus would make it monophyletic , with the sister clade being Megalolamna.
The cladogram below represents the hypothetical relationships between megalodon and other sharks, including the great white shark. Modified from Shimada et al.
Megalolamna paradoxodon. Otodus obliquus. Isurus oxyrinchus. One interpretation on how megalodon appeared was that it was a robust-looking shark, and may have had a similar build to the great white shark.
The jaws may have been blunter and wider than the great white, and the fins would have also been similar in shape, though thicker due to its size.
It may have had a pig-eyed appearance, in that it had small, deep-set eyes. Another interpretation is that megalodon bore a similarity to the whale shark Rhincodon typus or the basking shark Cetorhinus maximus.
The tail fin would have been crescent-shaped, the anal fin and second dorsal fin would have been small, and there would have been a caudal keel present on either side of the tail fin on the caudal peduncle.
This build is common in other large aquatic animals, such as whales, tuna, and other sharks, in order to reduce drag while swimming.
The head shape can vary between species as most of the drag-reducing adaptations are toward the tail-end of the animal. Since Carcharocles is derived from Otodus , and the two had teeth that bear a close similarity to those of the sand tiger shark Carcharias taurus , megalodon may have had a build more similar to the sand tiger shark than to other sharks.
This is unlikely since the sand tiger shark is a carangiform swimmer which requires faster movement of the tail for propulsion through the water than the great white shark, a thunniform swimmer.
Due to fragmentary remains, there have been many contradictory size estimates for megalodon, as they can only be drawn from fossil teeth and vertebrae.
Mature male megalodon may have had a body mass of Its large size may have been due to climatic factors and the abundance of large prey items, and it may have also been influenced by the evolution of regional endothermy mesothermy which would have increased its metabolic rate and swimming speed.
The otodontid sharks have been considered to have been ectotherms , so on that basis megalodon would have been ectothermic.
However, the largest contemporary ectothermic sharks, such as the whale shark, are filter feeders, while lamnids are now known to be regional endotherms, implying some metabolic correlations with a predatory lifestyle.
These considerations, as well as tooth oxygen isotopic data and the need for higher burst swimming speeds in macropredators of endothermic prey than ectothermy would allow, imply that otodontids, including megalodon, were probably regional endotherms.
In , Shimada and colleagues suggested large size was instead due to intrauterine cannibalism , where the larger fetus eats the smaller fetus, resulting in progressively larger and larger fetuses, requiring the mother to attain even greater size as well as caloric requirements which would have promoted endothermy.
Males would have needed to keep up with female size in order to still effectively copulate which probably involved latching onto the female with claspers , like modern cartilaginous fish.
Gordon Hubbell from Gainesville, Florida , possesses an upper anterior megalodon tooth whose maximum height is The first attempt to reconstruct the jaw of megalodon was made by Bashford Dean in , displayed at the American Museum of Natural History.
Dean had overestimated the size of the cartilage on both jaws, causing it to be too tall. In , John E. In , marine biologists Patrick J.
Schembri and Stephen Papson opined that O. In , shark researchers Michael D. Gottfried, Leonard Compagno , and S.
Curtis Bowman proposed a linear relationship between a shark's total length and the height of the largest upper anterior tooth.
In , shark researcher Clifford Jeremiah proposed that total length was proportional to the root width of an upper anterior tooth.
He claimed that for every 1 centimeter 0. Jeremiah pointed out that the jaw perimeter of a shark is directly proportional to its total length, with the width of the roots of the largest teeth being a tool for estimating jaw perimeter.
The largest tooth in Jeremiah's possession had a root width of about 12 centimeters 4. In , paleontologist Kenshu Shimada of DePaul University proposed a linear relationship between tooth crown height and total length after conducting anatomical analysis of several specimens, allowing any sized tooth to be used.
Shimada stated that the previously proposed methods were based on a less-reliable evaluation of the dental homology between megalodon and the great white shark, and that the growth rate between the crown and root is not isometric , which he considered in his model.
In , Shimada revisited the size of megalodon and discouraged using non-anterior teeth for estimations, noting that the exact position of isolated non-anterior teeth is difficult to identify.
Shimada stated that the maximum total length estimates, based on upper anterior teeth that are available in museums, are The most common fossils of megalodon are its teeth.
Diagnostic characteristics include a triangular shape, robust structure, large size, fine serrations, a lack of lateral denticles , and a visible V-shaped neck where the root meets the crown.
The tooth was anchored by connective tissue fibers , and the roughness of the base may have added to mechanical strength.
The anterior teeth were almost perpendicular to the jaw and symmetrical, whereas the posterior teeth were slanted and asymmetrical.
Megalodon teeth can measure over millimeters 7. Another nearly complete associated megalodon dentition was excavated from the Yorktown Formations in the United States, and served as the basis of a jaw reconstruction of megalodon at the National Museum of Natural History USNM.
Based on these discoveries, an artificial dental formula was put together for megalodon in The dental formula of megalodon is: 2.
As evident from the formula, megalodon had four kinds of teeth in its jaws: anterior, intermediate, lateral, and posterior. Megalodon's intermediate tooth technically appears to be an upper anterior and is termed as "A3" because it is fairly symmetrical and does not point mesially side of the tooth toward the midline of the jaws where the left and right jaws meet.
Megalodon had a very robust dentition,  : 20—21 and had over teeth in its jaws, spanning 5 rows. In , a team of scientists led by S.
Wroe conducted an experiment to determine the bite force of the great white shark, using a 2. In addition, Wroe and colleagues pointed out that sharks shake sideways while feeding, amplifying the force generated, which would probably have caused the total force experienced by prey to be higher than the estimate.
The resulting simulations identified higher levels of stress in megalodon teeth under lateral force loads compared to its precursor species such as O.
This suggests that megalodon teeth were of a different functional significance than previously expected, challenging prior interpretations that megalodon's dental morphology was primarily driven by a dietary shift towards marine mammals.
Instead, the authors proposed that it was a byproduct of an increase in body size caused by heterochronic selection.
Megalodon is represented in the fossil record by teeth, vertebral centra , and coprolites. Its chondrocranium , the cartilaginous skull, would have had a blockier and more robust appearance than that of the great white.
Its fins were proportional to its larger size. Some fossil vertebrae have been found. The most notable example is a partially preserved vertebral column of a single specimen, excavated in the Antwerp Basin , Belgium, in It comprises vertebral centra , with the centra ranging from 55 millimeters 2.
The shark's vertebrae may have gotten much bigger, and scrutiny of the specimen revealed that it had a higher vertebral count than specimens of any known shark, possibly over centra; only the great white approached it.
The coprolite remains of megalodon are spiral-shaped, indicating that the shark may have had a spiral valve , a corkscrew-shaped portion of the lower intestines , similar to extant lamniform sharks.
Gottfried and colleagues reconstructed the entire skeleton of megalodon, which was later put on display at the Calvert Marine Museum in the United States and the Iziko South African Museum.
Megalodon had a cosmopolitan distribution ;   its fossils have been excavated from many parts of the world, including Europe, Africa, the Americas, and Australia.
Megalodon inhabited a wide range of marine environments i. Adult megalodon were not abundant in shallow water environments, and mostly inhabited offshore areas.
Megalodon may have moved between coastal and oceanic waters, particularly in different stages of its life cycle.
Fossil remains show a trend for specimens to be larger on average in the Southern Hemisphere than in the Northern, with mean lengths of They do not suggest any trend of changing body size with absolute latitude, or of change in size over time although the Carcharocles lineage in general is thought to display a trend of increasing size over time.
The overall modal length has been estimated at Megalodon had a global distribution and fossils of the shark have been found in many places around the world, bordering all oceans of the Neogene.
Though sharks are generally opportunistic feeders, megalodon's great size, high-speed swimming capability, and powerful jaws, coupled with an impressive feeding apparatus, made it an apex predator capable of consuming a broad spectrum of animals.
It was probably one of the most powerful predators to have existed. That is to say it was higher up in the food chain. Fossil evidence indicates that megalodon preyed upon many cetacean species, such as dolphins, small whales, cetotheres , squalodontids shark toothed dolphins , sperm whales , bowhead whales , and rorquals.
The feeding ecology of megalodon appears to have varied with age and between sites, like the modern great white.
It is plausible that the adult megalodon population off the coast of Peru targeted primarily cetothere whales 2. Megalodon faced a highly competitive environment.
Such preferences may have developed shortly after they appeared in the Oligocene. Megalodon were contemporaneous with whale-eating toothed whales particularly macroraptorial sperm whales and squalodontids , which were also probably among the era's apex predators, and provided competition.
Fossilized teeth of an undetermined species of such physeteroids from Lee Creek Mine, North Carolina, indicate it had a maximum body length of 8—10 m and a maximum lifespan of about 25 years.
This is very different from similarly sized modern killer whales that live to 65 years, suggesting that unlike the latter, which are apex predators, these physeteroids were subject to predation from larger species such as megalodon or Livyatan.
Other species may have filled this niche in the Pliocene,   such as the fossil killer whale Orcinus citoniensis which may have been a pack predator and targeted prey larger than itself,     but this inference is disputed,  and it was probably a generalist predator rather than a marine mammal specialist.
Megalodon may have subjected contemporaneous white sharks to competitive exclusion , as the fossil records indicate that other shark species avoided regions it inhabited by mainly keeping to the colder waters of the time.
Sharks often employ complex hunting strategies to engage large prey animals. Great white shark hunting strategies may be similar to how megalodon hunted its large prey.
Unlike great whites which target the underbelly of their prey, megalodon probably targeted the heart and lungs, with their thick teeth adapted for biting through tough bone, as indicated by bite marks inflicted to the rib cage and other tough bony areas on whale remains.
Fossil remains of some small cetaceans, for example cetotheres, suggest that they were rammed with great force from below before being killed and eaten, based on compression fractures.
During the Pliocene, larger cetaceans appeared. Numerous fossilized flipper bones and tail vertebrae of large whales from the Pliocene have been found with megalodon bite marks, which suggests that megalodon would immobilize a large whale before killing and feeding on it.
In , Shimada and colleagues calculated the growth rate of an approximately 9. Megalodon, like contemporaneous sharks, made use of nursery areas to birth their young in, specifically warm-water coastal environments with large amounts of food and protection from predators.
Given that all extant lamniform sharks give birth to live young, this is believed to have been true of megalodon also. An exceptional case in the fossil record suggests that juvenile megalodon may have occasionally attacked much larger balaenopterid whales.
The Earth experienced a number of changes during the time period megalodon existed which affected marine life. Geological events changed currents and precipitation; among these were the closure of the Central American Seaway and changes in the Tethys Ocean , contributing to the cooling of the oceans.
The stalling of the Gulf Stream prevented nutrient-rich water from reaching major marine ecosystems, which may have negatively affected its food sources.
The largest fluctuation of sea levels in the Cenozoic era occurred in the Plio-Pleistocene , between around 5 million to 12 thousand years ago, due to the expansion of glaciers at the poles, which negatively impacted coastal environments, and may have contributed to its extinction along with those of several other marine megafaunal species.
As its range did not apparently extend into colder waters, megalodon may not have been able to retain a significant amount of metabolic heat, so its range was restricted to shrinking warmer waters.
Its distribution during the Miocene and Pliocene did not correlate with warming and cooling trends; while abundance and distribution declined during the Pliocene, megalodon did show a capacity to inhabit colder latitudes.
Marine mammals attained their greatest diversity during the Miocene,  : 71 such as with baleen whales with over 20 recognized Miocene genera in comparison to only six extant genera.
The extinction was selective for endotherms and mesotherms relative to poikilotherms , implying causation by a decreased food supply  and thus consistent with megalodon being mesothermic.
Competition from other predators of marine mammals, such as macropredatory sperm whales which appeared in the Miocene, and killer whales and great white sharks in the Pliocene,    may have also contributed to the decline and extinction of megalodon.
These may have occupied a niche similar to that of orcas before eventually being replaced by them. The extinction of megalodon set the stage for further changes in marine communities.
The average body size of baleen whales increased significantly after its disappearance, although possibly due to other, climate-related, causes.
Megalodon may have simply become coextinct with smaller whale species, such as Piscobalaena nana. Megalodon has been portrayed in several works of fiction, including films and novels, and continues to be a popular subject for fiction involving sea monsters.
Animal Planet 's pseudo-documentary Mermaids: The Body Found included an encounter 1. This program received criticism for being completely fictional; for example, all of the supposed scientists depicted were paid actors.
In , Discovery re-aired The Monster Shark Lives , along with a new one-hour program, Megalodon: The New Evidence , and an additional fictionalized program entitled Shark of Darkness: Wrath of Submarine , resulting in further backlash from media sources and the scientific community.
Fossil megalodon teeth can vary in color from off-white to dark browns and greys, and some fossil teeth may have been redeposited into a younger stratum.
The claims that megalodon could remain elusive in the depths, similar to the megamouth shark which was discovered in , are unlikely as the shark lived in warm coastal waters and probably could not survive in the cold and nutrient-poor deep sea environment.
Megalodon teeth are the state fossil of North Carolina.