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Science Frontiers ONLINE No. 74: Mar-Apr 1991 |
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Searching For Monster Sharks
Tantalizing reports surface now and then lending crediblility to the claim that there exists a very rare, deepwater shark that rivals the blue whale in size. We are talking 50-foot sharks and larger here; sizes that make the hero (or heroine) of the Jaws series seem minnow-like.
All of these hints come from the Pacific and focus on the possible survival of the shark Carcharodon megalodon, a monster relative of the great white shark. Megalodon is thought to have met its demise a million or so years ago. The word megalodon means "big tooth," and indeed the fossil teeth of this monster approach 6 inches in length. Sharks sporting teeth of this size could be as long as 50 feet. Measurements of the manganese dioxide layers accumulated on megalodon teeth dredged up from the seafloor suggest that it might actually have survived the Ice Ages and terrorized the Pacific as late as 10,000 years ago. Actually, some unfossilized teeth 5 inches long have been brought up by dredges, implying an even more recent existence.
Do scuba divers have anything to fear today? There are rare reports of huge versions of a shark resembling the great white but without the high dorsal fin. So, if the shark of Jaws scared you, think what a 50-foot version with 5-inch, serrated teeth could do to you and your boat. (Shuker, Karl P.N.; Fate, 44:41, March 1991.)
Comment. Admittedly, these recent data are soft, but there's no error about those teeth in the museums. New "living fossils" are being found all the time.