Sharks are some of the most mysterious and misunderstood creatures in the sea. They come in various shapes and sizes. Sharks are some of the most perfectly adapted creatures on earth, yet man knows very little about them.
Sharks belong in the same phylum, Chordata, along with mammals, reptiles, and other vertebrates (Perrine 23). Sharks then fit into the Chondrichthyes class of fish. This category includes all the fish that have skeletons made of cartilage, unlike other fish, whose skeletons are made of bone (MacQuitty 6). There are eight orders of sharks along with thirty families. They are classified due to the absence or presence of certain internal and external characteristics such as number of gill slits, fin shapes, and shapes of bodies (Coupa 16-17). An exact number of species has never been decided on. The best estimate of the number of species is between three hundred seventy-five and four hundred seventy-five. This number changes constantly (Perrine 14). Approximately four new species of sharks are discovered every year (Perrine 15).
The lengths of all these species vary in size from six and a half inches to about fifty (MacQuitty 6). The majority of all sharks, 83 percent to be exact, do not even reach two meters in length (Langreth 48). The four largest sharks in order are the Whale Shark, Basking Shark, the Great Hammerhead, and the Great White. The smallest shark is the Pygmy Ribbontail Catshark which can only reach nine inches (Coupa 2). When one thinks of a shark, they think of a generic streamlined and torpedo-like body of a Tiger Shark or Great White, but actually there is a huge diversity in the shapes of sharks ("Shark Information). One of the most awkward body shapes is that of the ray-like Angel Shark and its relatives. All sharks have one thing in common, a large caudal, or tail fin (Perrine 24). A shark's tail fin is one of its most prominent and important features. A shark's tail suits its way of life. There are many types of shark's tails such as the long whip-like Thresher's and the more triangular Great White Tail (MacQuitty 16-17). Most sharks also have two dorsal fins on their backs. They have a pair of pectoral or side fins. Shark skins are made of very coarse, teeth-like, scales called denticles (Perrine 23-24).
Sharks have rows and rows of teeth. Every time a shark loses a tooth, there is always a tooth to replace the one lost (MacQuitty 7). Sharks' teeth come in assorted styles depending on what the shark eats and how it catches its food (Perrine 14-15). A shark's tooth defines its personality and where it lives (Coupa 14-15). A shark's jaw is not solidly attached to the skull. They are held on only by tendons giving sharks the ability to sling their jaws out in front of their heads and open them very wide (Perrine 27).
A shark's cardiovascular system is similar to that of a mammal in that it uses a heart to pump blood through a system of arteries and veins. The larger and more active a shark is, the larger and more powerful its heart is. In general, the size and weight of a shark's heart is almost always proportionate to the size of its body (Stevens 65-66). Like all fish, sharks have gills, but unlike its bony fish relatives, they have multiple gills. In fact, they have between five and seven (Perrine 27). Sharks also don't have gill covers like their bony relatives do. Sharks do not have ribs, a usual occurrence in a vertebrate animal ("Shark Information").
Sharks have a digestive system, somewhat similar to that of a humans. A shark's digestive system consists of a stomach, an intestine, and an anus (Perrine 27-28). The liver is the largest organ in a shark's body. The liver makes up about twenty-five percent of a shark's total weight (Wexo 12). Their large liver keeps them from sinking (Perrine 28).
Sharks have an excellent immune system. A shark's immune system is thought to be very high on the evolutionary scale. Sharks are even thought to have cancer-fighting cells that are unmatched by any other creature on earth. No cancer or similar disease has ever formed or been found in a shark (Mestel). Most sharks are cold-blooded though some like the Great White have adapted and become warm-blooded (Perrine 35). Body form and warm-bloodedness are some of the ways in which sharks have become specialized (Stevens 56).
Sharks are highly advanced animals. They have large brains that have the same learning abilities as most small mammals (Perrine 8). A shark's keen senses make them excellent hunters. Each of their senses is used at different stages of the hunt (Perrine 42). The first of these senses is sight. Shark's eyes are similar to a human's (Langreth). The size and shape of a shark's eye depends entirely on where the shark lives (Coupa 38). It was originally thought that shark's were color blind, but, after much scientific testing, it was determined that sharks can see color. They tend to see more greens and blues than the other colors in the spectrum (Stevens 80). Sharks have a series of reflecting plates just behind their retina which makes their sight extremely sensitive and produces an "eyeshine" similar to that found in cats (Benchly 82). Another special characteristic of a shark is the ability to protect its eye during potentially hazardous situations. Some sharks have a protective membrane to achieve this purpose while others retract the eye back into the head (Perrine 28).
A shark's sense of smell is highly advanced and is very important to a shark (Perrine 39). A shark can smell its prey from distances as far as a mile away (Coupa 38). A shark can sense a chemical at concentrations as low as one unit per million units (Perrine 40). Some male sharks have such a highly advanced sense of smell that they can smell when a female has been in the area and follow her scent (Stevens 84). In fact, the sense of smell is so important to a shark, that it uses two thirds of its brain for smell information ("Tiger Shark"). Sharks have a specially adapted nose that some scientists call a "swimming nose". For those sharks with bad eyesight, its sense of smell often makes up for it (Coupa 38-39).
A sharks sense of touch is also highly advanced. It can sense vibrations from animals far from its location in the water. This is called "distant touch" (MacQuitty 18). All fish, including sharks, have a lateral line which enable them to have a very sensitive sense of touch. A shark's lateral line is located down the sides and on the spine of a shark. Sharks also have an excellent sense of hearing. Sharks can hear the sound of a struggling fish from far away (Perrine 39). Sharks can even hear the sound of a heartbeat from long distances (Gibbons 7). Sharks have a sense of taste though no special adaptations to this sense have been discovered. Shark have all five senses shared by humans and most other vertebrates, but it is one of the few animals that has a sixth sense. This sixth sense is the ability to detect electronic signals and fields created by other creatures and objects in the sea (MacQuitty 18). This sense is made possible by small receptors on the tip of the snout. A shark can even sense electric fields created by two AA batteries as far as a mile apart (Perrine 41).
Sharks, unlike mammals, but like other fish breathe through the use of gills (Stevens 66). Sharks breathe by extracting oxygen from the water (Perrine 27). A sharks respiratory system is specialized so that it can breathe even when it is not moving. Unlike bony fish, sharks can breathe while motionless (Stevens 66). Sharks have a slow growth and maturity rate. The rate of natural mortality for sharks is very slow. This slow rate of mortality corresponds with the slow growth and maturity and helps to keep the shark population in balance (Perrine 35-36). The average age for a shark is between twenty and thirty years old though some species may even live to be one hundred years old (Coupa 13).
"Sharks play an important role in evolution by removing the weakest, the sick and the dead so that the fittest can survive, they are evolution in action, the epitome of natural selection" (qtd. in "Shark Information"). Sharks eat a variety of foods. The shape of their teeth corresponds to the type of food they eat (MacQuitty 24). Most of the sharks are carnivores. They typically prefer fresh food but have been known to eat dead animals such as dogs and cows that have been thrown into the water (Coupa 30-31). As a smaller shark ages, its diet will usually change from eating small crabs, shell fish, and shrimp to eating fish and squid (Perrine 34-35). A preferred dish for a shark is a tender shark pup ("Beyond Jaws"). Sharks feed on anything from lobster to fish (MacQuitty 24-25). A larger shark might be caught eating a seal, squid, penguin, and other sharks (MacQuitty 28). Some of the largest sharks eat some of the smallest creatures in the sea, plankton , through filter feeding (MacQuitty 32-33). Some sharks have been known to eat almost anything from tin cans to sea birds to sunglasses (MacQuitty 49). Sharks need at least four days to digest the food they have eaten (Langreth). Some sharks have even been known to eat their own children (Coupa 31). Most sharks feed according to the "Feast or Famine" principle meaning eat as much as possible at certain times, and then go for a long time period without feeding (Perrine 35). Some shark can go a week or two without eating (Perrine 27). The only natural enemies to large sharks are whales, other larger sharks, and man (Coupa 36).
A shark's mating rituals are similar to that of humans. It includes courting which most often is a chase of the female by the male (MacQuitty 20). A shark's mating may be a rather brutal affair (Perrine 31). A male shark's sex organ is its claspers. The female sex organ is the cloaca. They function in the same way that mammal sex organs do. Another one of the shark's high evolutionary characteristics is live birth which is shared by mammals and a few other creatures (Perrine 8). Some sharks give birth by laying eggs but most give birth to live young (MacQuitty 21-22). There are three ways in which sharks deal with a fertilized egg: oviparity, ovoviviparity, and viviparity. Sharks which lay eggs are oviparous. The two ways in which sharks have live birth are through viviparity and ovoviviparity (Perrine 31-32). About thirty percent of sharks lay eggs while the other remaining seventy percent give birth to live young ("Shark Information"). After birth, sharks receive no assistance from their mothers (Perrine 32). A baby shark is called a pup and is born with a full set of teeth so it is born ready to fight and bite (Broekel 16).
Sharks live in all the world's oceans. Many swim in warm tropical waters while other prefer the freezing cold water of Antarctica and the Arctic (Coupa 26). Most sharks live in salt water though a few live in fresh water and estuaries or river mouths (MacQuitty 6). Some swim near the surface and others spend all their time far down in the depths of the oceans (Coupa 26). Sharks are very graceful swimmers. They propel themselves by beating their tails from side to side. Their pectoral fins along with their large livers aid sharks in keeping afloat (MacQuitty 14). Sharks normally cruise at speeds of less than one mile per hour . Sharks are capable of high speed bursts but they tire quickly ("Beyond Jaws"). Sharks are stereotyped as large solitary creatures, but most are far from that. Only the larger species such as the Great White and the Tiger Shark live solitarily. Most sharks live in small groups or schools. Some sharks, such as the hammerhead, have been seen in schools of one hundred or more (Stevens 89).
There are many species of sharks in the sea. One of which is the Great White. The Great Whites are probably the most mysterious sharks in the sea (MacQuitty 30). They are also one of the most well known sharks due to the bad impression given to them by movies such as JAWS. The Great White's Scientific name is Carcharodon carcharias which is very similar to the name of the huge ancient shark, Carcharodon megalodon (Arash 1).The Great White can grow up to twenty feet long or longer and weigh more than two and half tons (MacQuitty 28). The record length for Great White sharks is thirty feet and the record weight is more three and a half tons ("Beyond Jaws"). Great Whites live in cool to temperate coastal waters near North and South America, Southern Africa, the Mediterranean Sea, Southeast Asia, Australia, and New Zealand (MacQuitty 30). Even though Great Whites can be found all over the world, their populations are much denser near South Africa, Australia, and the California and Mexican coasts ("Cold Hard Facts"). Great Whites are the largest predatory fish in the ocean (Perrine 57).The Great White is the only species of sharks that can lift its head out of the water to sneak a peek at the surface. This is probably because its prey are the land living and surface swimming seals and sea lions (Coupa 42). Great Whites are the only sharks to regularly feed on marine mammals as well as tuna and occasionally sea birds, penguins, rays, turtles, and garbage (Perrine 57). Great White's have even been known to devour an occasional whale. A Great White's tooth can be up to three inches in length (Gibbons 21). Great Whites along with their relatives the Makos and Threshers are some of the only warm-blooded fish in the sea (MacQuitty 20). The Great White can reach speeds of fifteen miles per hour for small periods of time. Though it isn't THE fastest, it is one of the fastest sharks ("Cold Hard Facts").
The Great White is fast-moving, aggressive and intelligent; an extremely dangerous enemy when provoked (Coupa 45). Some people believe Great Whites are the number one people killer of all the sharks (Bishop 23). Great Whites are also the most infamous sharks as far as attacking people is concerned. Statistically, however, Bull, Tiger, and Nurse sharks attack more people ("Cold Hard Facts"). In fact, Great Whites are attributed with about one sixth of all attacks while Bull and Tiger Sharks each have about two thirds ("Cold Hard Facts").
The Great White has many nicknames. One of its nicknames is man eater because of the legends that state they set out to attack small boats and people (Shuttlesworth 93). Another nickname is White Pointer (Coupa 42). Some of its other nicknames are White Death, the Great Blue Shark, and the White Shark (Stevens 35). Despite its name, the only white part of a Great White is its underside (Shuttlesworth 94). People think killing a Great White is a sign of pride and courage, but it is not. Due to this mass killing of the Great Whites by trophy hunters and sport fisherman, Great Whites have been declared a protected species in places such as South Africa and California (Perrine 57).
Whale sharks are the largest fish in the world reaching at least forty feet and weighing thirteen tons. Some Whale sharks have been measured at sixty feet long (MacQuitty 32). Whale sharks can be found all around the world in warm oceans, both coastal and far from land (Perrine 45). The Whale shark's skin is the thickest in the world reaching up to eight inches thick. It is an oviparous shark which means it lays eggs. Its eggs are the largest in the world reaching about one foot in length (Gibbons 30). There are two theories as to why a whale shark is called a whale shark. One is that it eats like Baleen whales, meaning it filter feeds. The other is that they were mistaken for a whale due to their gentleness and huge size. Whale sharks are harmless to humans unless one is hit by their huge tail or knocked over in one's boat by this clumsy animal. Some Whale sharks have even been known to give divers a ride now and then. Despite their size, Whale sharks feed on some of the smallest sea creatures, plankton (MacQuitty 32). A Whale shark not only feeds on plankton, but entire schools of fish as well as squid (Perrine 45). Whale Sharks are very passive towards large marine mammals and have actually been attacked by Killer Whales and other sharks (Perrine 45).
Of all the sharks, the Hammerheads are probably the strangest due to odd shape of their heads. They are two types of Hammerheads: Bonnetheads and Wingheads (MacQuitty 42). They live in warm coastal water around the world. Its favorite food is the stingray, but will also eat small fish. The Hammerhead doesn't seem to mind the poisonous sting of its favorite cuisine, in fact, some Hammerheads have been spotted with dozens of string ray tail spikes in their bodies while showing little or no pain ("Surprising Sharks"). It is thought that the shape of a Hammerhead's head aids in spotting prey from away. Hammerheads are the most dramatic sharks because of their unusual appearance, but also because of the very large schools they form and travel with, sometimes with one hundred or more sharks. Hammerheads have very complex social interactions which helps to dispel the notion that they are simple-brained eating machines (Perrine 51).
Though not as strange as the Hammerhead, the Wobbegongs or Carpet sharks are very unusual. These unusual sharks have a flattened, frilly, well camouflaged appearance. They can be found on the Australian coast and the Asian Pacific coast. They eat many bottom dwelling creatures such as crabs, lobsters, octopus, and bony fishes (Perrine 61). The Wobbegongs of the Asian Pacific coasts are called bearded sharks because of the branched lobes around their mouths. People often complain of severe pain after stepping on the frills of these sharks. These sharks are bottom dwellers and are well adapted to be so (MacQuitty 38).
A Tiger shark is just a generic looking shark except for the tiger-like stripes it bears for much of its youth. These sharks are attributed with about one fifth of all shark attacks ("Cold Hard Facts"). They are sometimes called "swimming garbage cans" because they will eat almost anything: living, dead, and inanimate (Perrine 47). Once, a Tiger shark aided in solving a murder. This occurred when a shark had eaten the arm of a murdered man that was thrown into the ocean by the killers. The next day, the shark was caught, and when they began to open the shark to get resources from it, they found the undigested arm and gave it to the police believing it was a shark attack. They matched it to that of a missing man, whose body was later found somewhere in a field. They eventually found the murderers knowing that the arm belonged to the missing man (Coupa 31). Here are some other things that have been found in the stomachs of Tiger sharks: a barrel of nails, a torpedo, a case of wine, a suit of armor, a military uniform, and a chest full of treasures (Wexo 13).
Here are some other notable species of sharks. The fastest fish in the sea is the Mako shark. It has been thought to reach speeds of over sixty miles per hour (Perrine 63). The swift swimming Mako is also the highest jumper of the sharks. It can leap as high as twenty feet out of the water ("Surprising Sharks"). Sharks such as the Cookiecutter and Lantern sharks have the ability to glow in the dark. Cookiecutters, which only reach a couple feet in length feed on whales, seals, and dolphins by taking large chunks of their flesh in one bite. Cookiecutters attract their prey by their ability to glow (MacQuitty 44-45). The Bull shark can survive in very salty and fresh water. Some Bull sharks have even been seen swimming up some rivers such as the Mississippi and the Amazon (Perrine 69). These shark have also been attributed to about one fifth of all shark attacks by attacking swimmers in both rivers and seas (Source# 22). The ray-like Angel sharks get their name from their angel-like wings and can grow up to six and a half feet in length (MacQuitty 36). One of the weirdest and newly discovered sharks, the Megamouth, has the largest mouth of all the sharks but feeds only on tiny krill (MacQuitty 44). The enormous Basking shark along with the Whale and Megamouth sharks are the only plankton feeding fish in the sea. They feed in the same way as the Humpback Whale, "filter feeding" (Stevens 69).
Sharks have been in existence for about 400 million years (Wexo Inside Cover). For the past 70 million years, sharks have remained virtually unchanged and still comprise a dominant group ("Shark Information"). One of the largest sharks ever to have lived in the ocean is the Carcharodon megalodon. These ancient sharks lived over 15 million years ago. They reached over forty-three feet in length (MacQuitty 12). Carcharodon megalodon means "giant and rough tooth." Its teeth, along with its jaws were huge. Some of these extremely sharp teeth have been measured at eight inches in length (Gibbons 4). Some scientists theorize that the Carcharodon megalodon still lurks in the deepest depths of the sea, but most scientists think that they are extinct ("Cold Hard Facts"). Cladoselache was one of the oldest sharks ever to live. They lived over 360 million years ago and they grew up to about six feet in length. Hybodus lived over 240 million years ago and grew up to eight feet. Another ancient shark is the Ptychodus which lived over 100 million years ago (MacQuitty 12-13).
Just as sharks have ancient relatives, they have present-day relatives. All present- day sharks and their relatives belong to the class (large grouping of animals) Chondrichthyes (Perrine 13). Shark's closest relatives are rays, skates, sawfish, and chimeras (MacQuitty 7-8). Sharks, rays, and their relatives are all cartilaginous which means their skeletons are composed of cartilage (MacQuitty 8). Some scientists believe that rays are actually sharks, but that theory is not highly accepted ("Shark Information").
Sharks, along with other species, have symbiosis or mutual dependence on each other (Stevens 54-55). Sharks have "friendly" relations with such fish as the sharksucker, pilot fishes, and trevallies. Some fish swim along with sharks and rub up against the shark's side causing harmful parasites to be dislodged. Some of these fish eat scraps of sharks' meals and help sharks find more food. Some, such as the sharksuckers eat the afterbirth and umbilical cords of live born sharks (Perrine 36). The pilot fish actually guide or "pilot" the shark to food while getting protection from its enemies by hiding under or inside the shark (Stevens 54). Remoras often attach themselves to sharks and eat off the copepods infesting the shark. Copepods, or sea lice as they are sometimes called, are tiny shellfish that infest and live off the fins and gills of some sharks. Some shrimp even help bottom dwelling sharks in removing parasites (Coupa 29).
Over the years, myths and legends of sharks have sprung up. Not all shark myths are bad, though most are (Coupa 54). Over time, false tales and myths have sprung up describing wild feeding frenzies and vicious unprovoked attacks ("Beyond Jaws"). These myths have been strengthened by the exaggerated treatment of sharks in some movies. The movie JAWS, one of the most popular and highest grossing movies of all time, popularized sharks as terrifying blood-thirsty monsters that sought out human flesh (Coupa 52). Another movie, Blue Water, White Death, which came out before JAWS, started the first epidemic of shark hysteria throughout the world, though not as big as the Hysteria caused by JAWS (Stevens 109). The myth that sharks are hostile animals with a thirst for human blood has been helped along by the kind of bad publicity that attacks receive in newspapers and on television. In paintings and other art, artists portrayed sharks as huge man eaters that seem to set out to attack and eat people, capsize and destroy boats, and destroy or eat everything in their paths (Coupa 52-53).
There were some more positive shark legends. Sharks have been featured in the myths of many ancient coastal societies (Coupa 54). Native people living near the coast of the Pacific and Indian Oceans often considered sharks to be god-like or humans and also considered them a great symbol of power (MacQuitty 46-47). The Maori people of New Zealand made gods of sharks . Even some African tribes worship them. In India, people would let themselves be devoured by sharks in sacrifice, for that was an honorable thing to do (Coupa 98). In Hawaii, Native people feared and respected the shark-gods so much that they felt they must offer human sacrifice to them to keep them happy ("Beyond Jaws").
Each year there are between fifty and seventy-five people who are attacked by sharks. Out of those attacks each year, five to ten of them result in death (MacQuitty 48). The shark responsible for the most attacks is not the Great White or the Tiger, it is actually the small nurse shark (Perrine 10). The only sharks to have consistent records of fatal attacks are the Great White, Bull, Oceanic Whitetip, and Tiger sharks (MacQuitty 48). Only about two dozen species of sharks have ever been known to attack humans (Gibbons 15). The most shark attacks occur off the Atlantic Coast, coasts of Australia, Asia, California, and the southern tip of Africa (Coupa 44). Until the installation of shark nets, Australia was the shark attack capital of the world and was not close to being matched by any other country. Most shark attacks occur during the summer. When the summer comes, people go swimming and the sharks migrate into the same warm waters (Broekel 15). Most shark attacks occur during the day and the early evening (Shuttlesworth 92). Most often, shark attacks occur when people surf, swim, or scuba dive though they can occur when people escape from sinking ships and plane crashes over the ocean. All shark attacks worldwide are recorded by the International Shark Attack File (MacQuitty 48).
Before attacking, sharks always assume a certain position which can serve as a warning sign to prevent attacks (Coupa 44). There are many theories as to why sharks attack. One is just attacking for food. Another, more popular theory is defending territory. A third theory is that the attack was provoked in some way. The most popular theory to explain shark attacks on humans is the mistaken identity theory. It is thought that sometimes divers and surfers are mistaken for seals and sea lion, some larger sharks' normal prey (Coupa 40).
There are many ways to keep people from entering a shark-infested swimming area thus preventing a shark attack (MacQuitty 50). The first thing one should do to avoid attacks is avoid swimming in areas where multiple attacks have occurred, because unlike lightning, sharks do strike the same place twice. Also, one should not swim in areas where people are fishing or near ocean refuse dumps ("Beyond Jaws"). One should always pay attention to local authorities if a shark warning is posted, especially permanent warnings. It also good to have a lifeguard in the vicinity if one is swimming in water that they think is infested by sharks. One should never provoke or threaten a shark. One should never swim in areas where sharks might be if the water is murky or if one has a bleeding laceration (MacQuitty 48). Also, one should not swim in areas where there are large schools of fish, especially if there actions are erratic. If these safety measures are followed, one will have a very slim chance of being attacked by a shark ("Beyond Jaws").
There are many shark protection devices that are used to keep sharks away both near the shore and in the middle of the ocean. One of the most popular forms of shoreline protection is shark netting. Shark netting protects beaches by nets being strategically placed about half a mile from the shore and anchored to the bottom of the ocean floor. This form of protection often results in the death of sharks and other marine animals because they often get trapped and strangled in the shark nets . Another more expensive way is by enclosing the beaches with steel enclosures . A new experimental technique is by producing an electric field through which sharks can not pass (MacQuitty 50). If one is venturing farther into the middle of the ocean to observe large sharks, such as the Great White and Tiger, a metal shark cage is a safe refuge (Coupa 61). A new, less restricting chain metal suit is being used to protect divers while swimming with sharks in more remote ocean areas. This chain metal is the same used in medieval knight suits (MacQuitty 52-53).
The only consistency in shark attacks is there are no consistencies ("Cold Hard Facts"). The fact is sharks are not inherently vicious and the only reasons they attack any creature including humans is for food or when they feel threatened ("Beyond Jaws"). Of all the sharks, not one of them includes humans among their regular items on its diet (Perrine 14). In reality, even those people who are most often in the sea are more likely to be injured in a car crash or by bitten by a snake or spider (Coupa 52). The truth is that the most deadly creature on earth, apart from humans, is the honey bee (Perrine 13). A person is more likely to be struck by lightning than to be attacked by a shark (Perrine 18). "If shark really wanted to eat people they would, but they don't usually" said one scientist (qtd. in Langreth). Drowning in the United States outnumbers shark attacks 1,000 to one. Contrary to what Hollywood may want the people to believe due to movies such as JAWS, sharks do not normally attack by launching a frenzied assault and immediately shredding its victim ("Beyond Jaws"). Peter Benchly, author of JAWS was quoted as saying the following about his creation, "My research for the book was thorough and... for its time. I did my studying. I realize now that I was very much a prisoner of traditional conceptions. And Misconceptions" (qtd. Benchly 33). All shark attacks are not intended to be fatal , in general, sharks only bite once and then leave. If they intend on eating their victim, they will come back after the victim is dead because they do not want to deal with the struggling victim ("Beyond Jaws"). In general, shark attacks should be called "shark defenses" because the shark is usually defending itself against human provocation). The reason why sharks have little interest in attacking and consuming humans is this: there were no people around when their feeding habits formed (Perrine 13-14). Humans are actually more deadly to sharks than sharks are to humans (Perrine 16).
People have found a use for every part of the sharks body. People kill sharks for their meat, skin, teeth, liver oil, as well as for sport (MacQuitty 58). Ever since the days of old, people have been using sharks. Native people from all around the world used shark skins for such things as drum heads and kitchen tools (MacQuitty 46). Some native peoples used shark skins as a form of sandpaper (Gibbons 26). The ancient samurai often used shark skins for sword grips (MacQuitty 60). Native New Zealanders, the Maori, used shark teeth for a variety of uses such as combs, jewelry , and weapons (MacQuitty 46). Native Americans, especially those from the West Coast used shark teeth for arrowheads and jewelry (Gibbons 26). The crafty Australian Aborigines discovered the uses of shark liver oil many hundred years ago (Coupa 54).
Over the years, many more modern uses of sharks have been developed. One of the parts of a shark that is marketed in the health care today is shark liver oil. The liver oils of a shark contain many healthy substances such as Vitamin A, which is important for human sight and Squalene, which is also used in many cooking oils. In some countries, such as India, people believe that the oils from shark livers can heal almost any illness (MacQuitty 61). The liver oils of some sharks, such as the deep-sea dog fish, are thought to contain ingredients that can lower blood cholesterol and prevent clotting in the heart and other arteries. Scientists are investigating ways to use shark liver oils in human foods so that many people can utilize its healthiness (Coupa 58-59). Another popular use for sharks in health care is what some people say is a cure for cancer. Many companies have been using shark cartilage and marketing it as a miracle cure. Most experts say that the "miracle cure" is a hoax and to use the shark for more important things ("Sharks: Hunters Hunted"). Shark cartilage is also used in treating even the most severe burns. Shark cornea have been successfully transplanted in the place of human cornea (Coupa 59). Sharks currently form part of the staple diets of people as diverse as Vietnamese, Indonesians, and Sicilians (Coupa 58). In Japan, sushi or raw fish made of shark is very popular. In many Southeast Asian countries, shark fin soup, a soup made of ground shark fin, is a delicacy (MacQuitty 60-61). Shark fins can sell for as much as 500 dollars per kilogram in Southeast Asia (Flershannon). Oils of sharks are not only used in health care but in the cosmetics industry . You can find these oils present in many cosmetics such as lipstick (MacQuitty 34). Squalene, the before mentioned chemical, is present in many skin moisturizers (Coupa 58). Shark oils are also used in many anti-aging creams. Shark skin is used in making leather goods such as belts and wallets (MacQuitty 60-61). Shark leather is stronger than the usual leather made of cattle hides (Coupa 2). Shark carcass is used as a fertilizer in many countries around the world. People often buy and sell shark jaws and teeth as souvenirs when visiting coastal tourist spots (MacQuitty 60-61). Shark teeth can be used as decorations, jewelry, and ornaments (Coupa 59). Shark jaws are also popular trophies in the same way that people show off the head and/or horns of a deer. Some people mistakingly think that wearing shark teeth make them look as tough as the animal from which it comes (MacQuitty 60-61).
Compared to the 10 to 15 people killed by sharks annually, over 100 million sharks are killed during the same time periods (Perrine 17). The fact is the surfer is safe, but the shark must now face a pack of humans with high-tech equipment waiting to kill him for a fin, trophy, cartilage, or food. Sharks are very important to their ecosystem because they are top level carnivores. The effect of removing too many would be that there would be no predator for the animals that they eat (Hendy). Sharks are killed for many reasons including fear, food, sport, and worst of all pure greed (Perrine 17). Human exploitation of wild animals like sharks can cause a serious decline in their numbers, if more animals are killed than can be replaced by young sharks. Naturalists and other people are concerned because sharks are threatened by overfishing and destruction of habitat. Though some people think fishing for sharks is a "fun" sport or a way of making money, they are really destroying the balance of nature (MacQuitty 58). Shark finning may be the cruelest trade of the decade (Flershannon). Sometimes sharks' fins are just cut off, then the sharks are just thrown back into the ocean unable to swim and to die (MacQuitty 58). The economic impact of a shark extinction would be tremendous. This would cause an imbalance in some ecosystems that might result in a decline in the population in tasty marine life. An example of this is when a shark population was overkilled in a certain region, the octopus, the shark's prey began to flourish. This caused the lobster industry in the region to be ruined because the overly populated octopus community ate too many lobsters (Perrine 20). Since sharks are slow to reproduce, it would be hard for them to "bounce back" from over fishing. Eliminating sharks would change the whole ecology of the ocean. If man kills too many sharks, one will never get the full experience of being in a natural ocean again. Many shark populations are facing extinction due this overkill (Perrine 17-18). Just as man is beginning to understand sharks, they are killing them all off. "Many people fear them, but few people understand them. They can be eight times as large as a human or so small that they can fit into your hand", said one scientist while discussing the topic of the shark "overkill" (qtd in Coupa 8). Man is just beginning to take on the difficult task of studying sharks. Little is known about most sharks' behavior in the wild. Studying many sharks in the wild is almost impossible because of their high speed swimming, the fact the live in deep waters, and because they are almost constantly moving (MacQuitty 54). The United States has their own shark research plan. It is part of the American Institute of Biological Sciences (Shuttlesworth 90). Scientist often use electronic tags similar to those used on land animals to track and record information on sharks. Some species of sharks can be taken to aquariums to be studied and viewed. Only a few select species such as the Tiger Shark, the Atlantic Nurse, Bull, and Hornsharks can survive for long periods of time in captivity, though most species can not (Stevens 86-87). Unlike dolphins, sharks do not have as much good publicity or the sweet appearance which is needed to encourage people to start organizations to save them. Our National Government has set up to the National Marine Fisheries Service to protect sharks along with other aquatic species. Some countries have set them as protected species ("Sharks: Hunters Hunted"). There are a few small campaigns similar to "Save the Dolphins" such as "Save the Shark" and "Earthwatch" that are devoted to saving these great animals (MacQuitty 62).
Sharks are some of oldest creatures on the planet earth. Man has yet to begin fully understanding these wonderful masters of the sea. Until man can overcome its fears and misconceptions of these great creatures, they will never truly understand them. It is important that man not destroy the shark for the ocean and land world, as we know it, will never be the same.

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