Megalodon
From Freepedia
| Megalodon Conservation status: Fossil | ||||||||||||||||
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| Image:Megalodon tooth.jpg | ||||||||||||||||
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| Carcharodon megalodon Agassiz, 1843 |
Megalodon is also a tradename for a make of rebreather for scuba diving.
The Megalodon or Megatooth shark (Carcharodon megalodon, from ancient Greek, megalos + don, lit. "big tooth") was a giant shark that lived between 5 million and perhaps as recent as 15,000 years ago, recent enough to have seen our ancestors.
The Megalodon is known only from fossil teeth and a few fossilized vertebral centra. The teeth are in many ways similar to great white shark teeth; recent studies cited by Roesch suggest Megalodon was a "close relative" of the great white. Some estimates of this creature's size range up to 45 feet (about 14 metres). Previous much larger reconstructions of the shark's size, up to about 100 feet (30 m), are generally considered inaccurate.
Around 1995 the species was proposed to be placed in the new genus Carcharocles. To date this has not been resolved.
Some recent reports of large shark-like creatures have been interpreted as surviving Megalodons, but such reports are generally considered misidentification of basking sharks, whale sharks or other large creatures. It is possible, but unlikely, that some of these sightings might be due to abnormally large great whites.
Relict
While most mainstream experts contend that available evidence suggests that the Megalodon is extinct, the idea of a relict population seems to have seized the public imagination.
Megalodon teeth have been discovered that some argue date as recently as 10,000 to 15,000 years ago, perhaps making the species' extinction a recent event, and making it more conceivable that Megalodon might yet survive in the deep ocean, living on the heat from hydrothermal vents.
Others have countered that such recent estimates are inaccurate, and "claims of post-Pliocene C. megalodon ... are erroneous" and based on outdated testing and methodology. [1] Roesch and others also note that Megalodons were probably coastal sharks, and that deep-sea survival is extremely unlikely.
In addition, bones and carcasses of very large sperm whales have reportedly been found with megalodon teeth jammed into them. One famed example is this, told by Australian naturalist David Stead:
- "In the year 1918 I recorded the sensation that had been caused among the "outside" crayfish men at Port Stephens, when, for several days, they refused to go to sea to their regular fishing grounds in the vicinity of Broughton Island. The men had been at work on the fishing grounds—which lie in deep water—when an immense shark of almost unbelievable proportions put in an appearance, lifting pot after pot containing many crayfishes, and taking, as the men said, "pots, mooring lines and all". These crayfish pots, it should be mentioned, were about 3 feet 6 inches [1.06 m] in diameter and frequently contained from two to three dozen good-sized crayfish each weighing several pounds. The men were all unanimous that this shark was something the like of which they had never dreamed of. In company with the local Fisheries Inspector I questioned many of the men very closely and they all agreed as to the gigantic stature of the beast. But the lengths they gave were, on the whole, absurd. I mention them, however, as a indication of the state of mind which this unusual giant had thrown them into. And bear in mind that these were men who were used to the sea and all sorts of weather, and all sorts of sharks as well. One of the crew said the shark was "three hundred feet [90 m] long at least"! Others said it was as long as the wharf on which we stood—about 115 feet [35 m]! They affirmed that the water "boiled" over a large space when the fish swam past. They were all familiar with whales, which they had often seen passing at sea, but this was a vast shark. They had seen its terrible head which was "at least as long as the roof on the wharf shed at Nelson's Bay." Impossible, of course! But these were prosaic and rather stolid men, not given to 'fish stories' nor even to talking about their catches. Further, they knew that the person they were talking to (myself) had heard all the fish stories years before! One of the things that impressed me was that they all agreed as to the ghostly whitish color of the vast fish. The local Fisheries Inspector of the time, Mr Paton, agreed with me that it must have been something really gigantic to put these experienced men into such a state of fear and panic."
There is a theory that Carcharodon megalodon when adult fed largely on whales and went extinct as the polar seas became too cold for sharks, letting whales go out of reach of sharks for the summer.
A supposed surviving population of Megalodon sharks has been the subject of fictional novels, including several by Steve Alten, and a feature-length movie entitled Shark Attack 3: Megalodon.
External links
- Megalodon: Shark Glossary
- An impressive photograph of this shark's jaw
- More photos
- Carcharodon or Carcharocles?
- A Critical Evaluation of the Supposed Contemporary Existence of Carcharodon megalodon by Ben S. Roesch
- Does Carcharodon Megalodon Still Exist? by Richard J. Ravalli, Jr.
- Reconstructing Megalodon
