True or False: Dispelling Myths About Sharks

The first thing I think of when I hear the words 'shark attack' is the Hollywood blockbuster, JAWS. Hollywood has done an amazing job of terrifying the public of such a magnificent, prehistoric creature. There are so many myths and legends about sharks and shark attacks that none of them seem quite real to me anymore. So, being of a curious nature, I decided to do a little research and see if I could possibly separate the difference between myth and fact. I have been quite interested in this particular topic for a while now, and I made the most out of this opportunity to learn something new and possibly prove myself wrong on some of my hypotheses.

By understanding the biological aspects of the shark I was able to come to a better understanding as to why shark attack numbers have been on the rise in recent years, most recently being the "feeding frenzy" down in Florida back in 2001 (8). Biological components of any animal will often explain why it does what it does, and hopefully restore the proper respect the animal deserves. The question I am trying to answer here is: "Why do sharks attack people?"

All sharks have jelly-filled pores on their noses, resembling little blackheads, which are known as a shark's "sixth sense" (6); these pores are able to detect bio-electrical currents from bodies underwater, for example a heartbeat (6). If this so-called 'sixth sense' is highly tuned, then how does that explain attacks on humans? The great White is most famous for how it kills its prey. They use what is called the "sneak attack" (10); the sneak attack begins with the shark circling its unsuspecting prey then swimming away down toward the ocean floor (1). Once it hits a certain depth, it quickly turns around and propels itself vertically towards its prey (thanks to its oil-filled liver instead of a swim-bladder) (3), jumping out of the water about 15 feet with its prey, then body slamming itself and its food back into the water (5). Afterwards, the shark swims away leaving its food to bleed to death; it then returns to finish its meal (5). However, the bull and the tiger are usually not seen before they bite (similar to the Great White), but once they have their prey in their mouths they will not let go; they are the most persistent hunters in the ocean (10). Important biological information about sharks has been established and now we can move on to proving or disproving the myths about the ocean's greatest predators.

Let's start with myth number one- sharks attack surfers because they have poor eyesight, thus leading to a case of "mistaken identity". I believe that this myth has some relevance to it. However, when I had conducted my research I found that this goes under the false column. Sharks' eyesight is extremely good, in fact, even better than a human's (6). It is a very sensitive and powerful sense organ. Most sharks either have a nictitating membrane, white and tough in texture, which closes over their eyes like an upside-down eyelid when feeding or they just simply roll their eyes back into their head (6). Sharks do not do this before they bite their prey; it is only after they have determined what it is that they are eating that they close their eyes (7). The larger the shark's eye, the farther and better it can see (7). When hunting in the dark, some sharks have a thin yellow-color layer over their eyes, which enable them to see reflecting light (2). Think of shark vision as similar to a dog's; they see in black and white, so lighter colors will appear brighter and darker colors will appear closer to black (8). Sharks are attracted to bright and shiny colors so be extra careful of what you wear in the water. There have been many dissections done by many biologists to provide physical proof that sharks have great eyesight. One particular dissection was performed on a Great White's retina by R. Aidan Martin, the director of Reefquest Centre for Shark Research and the results were conclusive with other studies performed in the past few years (4). The results biologically proved that sharks, Great Whites in particular, are "highly visual creatures and possess a very high order of visual acuity" (4). Another important fact to state here that concerns the "mistaken identity" myth is that even from underwater, we humans look nothing like sea lions or sea turtles. We swim in a jerky, awkward fashion, whereas everything else in the ocean has a gentler flow to it. If anything, the shark will be more inclined to stay away from something that looks like it might move in an unpredictable pattern (4).

The second myth is by far the most known around the world- sharks are man-eaters and they are out to get us. I believe this myth to be false; according to my research, this also goes under the false column. There is tons of evidence that disproves this myth. Most evidence is of the biological nature, but there is one in particular that almost everyone is familiar with- Hollywood. What most people do not know about this film is that it was based on true-life events that occurred in New Jersey back in July of 1916. It is the case of the New Jersey Man-Eater. In July 1916 there were several severe shark attacks within the same area of Matawan Creek, NJ. For about twelve days, this residential area was terrorized by vicious shark attacks that left 4 people dead and 1 severely injured (9).

This story was portrayed very negatively in the media although, there is one thing that was not taken into account- the type of attack. There are three different types. The hit-and-run is the most common; the shark will come up, take a bite and then leave with the realization that a human is not its normal prey (5). The bump-and-bite is less common but often results in greater injuries and more fatalities; this type of attack usually happens in deep waters where divers and swimmers are sometimes found (5). The sneak attack is by far the most deadly since it consists of a bunch of repeated attacks and/or multiple bites; it is the least common but when it does occur, the shark is either coming off a feeding frenzy high or is displaying abnormal antagonistic behaviors (5). The proof here is in the first bite. When a shark goes after its prey, the first bite is the hardest and deadliest (1). Most shark attacks on humans are usually recorded with one bite that is not as devastating (2). Since most sharks do their hunting in the open sea, the only time they could actually, truly have the potential to accidentally bite a human would be when they linger around sandbars or are stuck between sandbars when the tide pulls out (5). Ironically, we as humans have a better chance of getting killed by a falling coconut or winning the state lottery than getting attacked by a shark (1).

All other evidence that I have gathered is from biological studies or biologists themselves. For example, concerning the top 3 deadliest sharks 3 different biologists have different opinions as to why these sharks are most likely to bite humans. Robert Hueter, director of the Center of Shark Research at Mote Marine Laboratory in Sarasota, FL believes that "the unusually high levels of testosterone and extremely aggressive, territorial behavior in bull sharks makes them more likely to attack something that is new to them or that they feel is a treat" (10); he also states that "these sharks are more likely to be found prowling the bottoms of shallow waters where humans are treading (10). As far as Great Whites are concerned, Sean VanSommeran, director of the Pelagic Shark Research Foundation in Santa Cruz, CA concurs with biologist Peter Ryle of the Point Reyes Bird Observatory on the fact that "most of the Great Whites that attack humans are really only juvenile sharks, about 8 to 12 feet in length, that are inexperienced hunters that are still learning the difference between 'food' and 'not food' (10). Tiger sharks are a bit different. According to Rocky Strong, a shark biologist associated with the Jean-Michael Cousteau Institute, tiger shark attacks are happening more often in Hawaii because "there has been a recent increase in the number of sea turtles since they were protected in the 1970s. The turtles swim close to shore, the shark will follow; it has a very persistent nature, similar to that of the bull shark" (10).

Although most biologists and scientists have not been able to predict exactly when, where and why a shark will attack (7), shark attacks do happen; it is something we all must come to accept. Some end up being deadly, others not. What is certain about these "attacks" is that they are usually provoked. Sharks do not intentionally attack humans because they are looking for prey or are hungry; in truth, sharks do not even really feel hunger as they can go for a long time without eating (2). The only way a shark can possibly intentionally attack a human is if said human is in its hunting territory at feeding time or if the shark feels threatened by said human's presence (2). But mostly, sharks are usually provoked in some way, shape or form to attack a human; anything from bright colors and jewelry to splashing will entice a shark to come and investigate this new and unfamiliar being (5). The jelly-filled pores on the sharks' noses allow for them to make a connection in their brain early on in life as to what is and is not food (6). If they happen to come across a human either early or later in life, then they will either know or not know that a human is not a source of food, respectively; the only plausible reason for a shark to attack a human if it has already come across one in its life is that the human is something new in its familiar habitat (8).

A study performed by the Reefquest Centre for Shark Research, headed by R. Aidan Martin, came to the same conclusion- that shark attacks are usually provoked in some way (4). They have stated that the shark is just reacting to something that it is not used to having in its normal environment; shark attacks are usually the result of curiosity on the animal's part or a self-defense mechanism due to the animal feeling threatened by the human's presence (4). It is never the shark's intention to kill; death from shark attacks mainly results from a combination of blood loss and shock (1). To be able to understand these creatures of the deep more clearly scientists and biologists are in the process of tracking and monitoring sharks. They are accomplishing this via a satellite tracking system that responds to tube-like information recorders that are tagged on the sharks' backs; they eventually fall off once their memory is full and float to the surface, transmitting the information they had gathered (1).

As you can see, not every myth is true. These two examples I have chosen to investigate just so happen to be false. I have proven myself to be wrong as I thought, before my research, that sharks did have poor eyesight and that, that was a huge reason why people are attacked by sharks. As for the other myth, I had a hunch that sharks were not out to get us and that it was not a case of "mistaken identity". I have learned much from my research, proving myself wrong as well as right in some cases, and I hope that in the future I can pursue this topic a bit more.

1. http://dsc.discovery.com
2. http://www.scuba-doc.com/shrks.htm
3. http://www.amonline.net.au/FISHES/students/dissect/swimbladder.htm
4. http://www.elasmo-research.org/education/education.htm
5. http://scuba.about.com/od/sharks/a/sharksattack.htm
6. http://www.geocities.com/rainforest/canopy/3018/biology.html
7. http://www.nhm.ac.uk
8. http://www.time.com/time/2001/sharks/cover.html
9. http://www.njhm.com/matawanmaneater.htm
10. http://www.time.com/time/2001/sharks/cover2.html