Shark Myths Dispelled
from the book, "Petrified Lightning"
Shark Myths Dispelled
At the beginning of World War II the U.S. Navy issued survival manuals to naval and army personnel traveling on troopships. The manuals contained information guaranteed to make the readers shark wise, or at least to dispel fear of sharks. Unfortunately, readers were told that sharks are slow—moving, cowardly, and easily frightened by splashing, although it is almost common knowledge that sharks are very fast swimmers, they fear and retreat from nothing, and splashing only attracts their attention. The manual further advised that someone caught in the water with a shark should first knife the shark, then immediately "swim out of the line of his (the shark's) charge, grab a pectoral fin as he goes by, and ride with him as long as you can hold your breath." With advice that appears to have been assembled by a hungry shark, it's almost a miracle that the United States won the war.
That many troops confronted by sharks took advantage of this manual of shark advice is doubtful. However, two airmen downed in the Pacific did use the manual. They had inflated their life vests and were in the process of tying themselves together so they would not drift apart. To multiply their uneasiness, they saw a large shark fin circling them about 30 feet away. In desperation one of the men threw the shark manual at the predator as it closed in. The shark devoured the manual with apparent relish. As it chewed, it seemed to assimilate the book's contents, for it swam away without bothering the airmen (the very shark behavior explained in the book!). Less than an hour later the airmen were picked up by a rescue ship.
In 1958 a group of 34 scientists from several countries met in New Orleans to consider possible ideas for developing an effective shark repellent. One result of this meeting was the development of the Shark Research Panel, an assortment of scientists committed to researching shark behavior and especially to studying shark attacks. The U.S. Navy, in cooperation with the Smithsonian Institution, worked closely with this group of scientists. Over a period of nine years they logged and analyzed some 1,600 attacks, the earliest of which involved a seaman who had fallen overboard in 1580. Records suggest that his demise somewhere between Portugal and India was exceedingly gory. The study dispelled some long—held myths about sharks.
One very popular belief is that the presence of porpoises in the water means that no sharks are about, since the porpoise is one of the few creatures sharks seem to fear. In reality sharks and porpoises frequently inhabit the same water but, for the most part, tend to respect and ignore each other. Another myth, thoroughly exploited by television, movies, and books, is that a porpoise will defend a human from an aggravated shark attack. This is purely a pipe dream. When an attack is in progress, the porpoise wisely swims off to avoid the possibility of being in the way of a frenzied feeding session.
Writers and illustrators have tantalized readers with images of triangular fins circling a hapless swimmer as sharks prepare to charge and mutilate in a mass attack. Most attacks, however, are made by a single shark that the victim rarely sees before being struck. Although the victim may be bleeding badly, other sharks in the vicinity usually do not participate. The prey is the property of the original attacking shark. Investigators are beginning to believe that human blood is not the strong stimulant it has been presumed to be, but a string of bleeding fish on a diver will immediately attract a shark's attention.
Massive shark attacks do occasionally occur, usually after a major maritime disaster. As one might expect, throngs of sharks are quick to intrude in waters around naval battles such as those that took place during World War II. Several surviving sailors on rafts recall with helpless horror the ocean's surface dotted with circling shark fins that engaged in a frenzy of feeding on dead and dying bodies floating on the water. Unfortunately, this is not a myth.
The next myth, a very popular one, can be disregarded. Most people imagine that fatal or maiming shark attacks involve a monstrously huge shark in deep water far offshore. A statistical investigation of shark attacks shows that about two—thirds of them take place in water little more than waist deep, and in about half of these incidents the shark is less than six feet long.
On February 26, 1966, in the middle of the afternoon on the south coast of New South Wales, a 13—year—old boy was wading about 30 yards from shore in less than five feet of water when his right leg was seized by a shark. He tried to beat the creature off and in desperation even leaned over and bit the shark on the snout. Still it held on, and the boy's screams resulted in the ringing of the shark warning bell.
Lifeguards arrived on the scene but could see no shark—just a very frightened boy standing in shallow water. One waded out and tried to pull the boy ashore but couldn't budge him. The man felt along the boy's immobile leg until he touched the shark. In record time he withdrew his hand and signaled his associates for help. It took six men to drag the boy ashore with the shark doggedly attached to his leg. The jaws of the shark, an eight—foot great white, were pried loose from the boy on the beach. The boy survived the loss of excessive amounts of blood but walked with a slight limp for years. As for the shark that bit him, its days were over.
Some definite conclusions emerged from the systematic study of shark attacks. One is that attacks occur, not surprisingly, in direct proportion to the incidence of sharks and humans sharing the same waters. Most of the near—shore attacks are carried out by the great white and tiger sharks that frequent the shoreline. They are the true villains, but most of these sharks are relatively young and therefore not very large. The white—tipped shark is suspected of being the principal predator of people forced into the open sea as a result of some type of maritime disaster. The circling shark fins observed by surviving sailors after deadly naval battles were probably those of white—tipped sharks.
In the 1950s abrupt and unpredicted attacks on scuba divers made headlines. The great white sharks in the chilly, murky waters off California were the offenders. On July 14, 1959, just off San Diego, two men were diving for shellfish in about 24 feet of relatively clear water. Suddenly one of the men began to yell for help and went under. The companion looked down and through his face mask saw his friend wreathed in blood, protruding trunk first from the mouth of a 20—foot white shark. This was the last time the attacked diver was ever seen.
Attacks have continued to the present, although these same sharks had almost ignored humans before that time. The change in behavior does not seem so far—fetched when one considers that scuba diving became a popular sport in the 1950s. Great white sharks, who have been feeding off the California coast for thousands or even millions of years, can easily mistake people in black wet suits for seals in these dim cloudy waters. Scientists believe that most shoreline attacks are really a mistake in identity; but once it latches on to a human, the chance of the shark's just spitting the victim out is very unlikely.
In 1964 a commercial fishing boat dredged some fossil shark teeth off the coast of Maine. The teeth were over four and a half inches wide at the base and just slightly over four inches long. Teeth of this huge sea monster, Carcharodon megalodon, have been dredged up many places in the world, particularly off California. C. megalodon's length, based on the teeth, could have reached over 60 feet and its weight more than 50 tons; it was certainly big enough to swallow a small truck. This species of shark, extinct for about 20 million years, probably satisfied hunger pangs by feeding on whales.
Shark lovers may be comforted by the fact that a near relative is among the living. It is Carcharodon carcharias, the great white shark described earlier as the culprit in the San Diego attack. This modern species rarely exceeds 20 feet in length, and its sharp teeth are usually less than two inches long. Recent dredging just off San Francisco Bay brought up shark teeth about five inches long. Shades of C. megalodon, except that these shark teeth were not fossil, but definitely recent.
However menacing the image of the killer shark, the odds against being killed by one are 300 million to 1. Sharks, in fact, have far more reason to fear humans than humans have to fear them, because fishermen are now slaughtering sharks at the rate of 100 million a year. This fish, a favorite prey in sportsfishing, is hunted intensely for the grill in U.S. restaurants and drowns in drift nets set for tuna and squid. And every year, over seven million pounds of shark fins are sold to merchants in Hong Kong. According to legend, shark—fin soup imparts sexual, spiritual, and financial powers—to anyone who can afford $50 dollars a bowl.
Shark populations have suffered disastrously from this last myth. In 1991 alone, the fins of over 3.2 million sharks were collected for shark—fin soup. After its dorsal fin is harvested, the shark is usually tossed back into the sea; shark fins are 30 times as valuable as shark fillets. Unable to swim, the unfortunate shark soon starves to death. Because shark populations are being decimated worldwide, authorities are trying to curtail fin harvests. And their argument is sound: starving on the bottom, tiger sharks or others who eat humans will doubtless crawl to shallow water where they can find easy human prey.