Many movies and stories of shark attacks lead us to believe that all sharks are dangerous and waiting to devour us with their razor sharp teeth. However, information on shark ecology has provided insight into their behaviour. Large sharks feed on lesser ones, therefore, the habit of segregation by size appears vital to the survival of smaller shark species. In a uniform grouping, there is a clear dominance between various species, thus proving a definite nipping order. All sharks stray away from hammerheads, whose ease of movement enhanced by the rudder effect of the head gives them a swimming advantage over other sharks.
Thankfully, swimmers and surfers are not sharks' favorite meal. They prefer sea lions, sea turtles, fish, whales, and seals. Most shark attacks occur near the shore, in the surf zone and sandbars, because their natural prey live in these areas. But attacks also take place in steep underwater drop-offs, where divers often swim. Sharks have to make quick decisions to capture food and therefore sometimes the predator misinterprets humans for delicious seafood. When attacking their prey, sharks use their teeth to generate 40,000-pounds of pressure per square inch that crush flesh and bones in a split second. This insane amount of bone crushing damage that a shark can inflict is what makes humans so terrified of seeing that tail fin swimming around so close to us. The most deadly shark species are the white shark (Carcharodon carcharias), the tiger shark (Galeocerdo cuvier) and the bull shark (Carcharhinus leucas).
Sharks circle their prey, appearing seemingly out of nowhere and frequently approaching from below. Their feeding behaviour is triggered by numbers and rapid swimming when three or more sharks appear in the presence of food. Activity progresses from tight circling to rapid crisscross passes. Under strong feeding stimuli, excitement can intensify into a sensory overload that may result in cannibalistic feeding, or “shark frenzy,” in which injured sharks, regardless of size, are devoured.
Thanks to the movie Jaws, the great white’s reputation as a ruthless man-eater pervades to this day. There are numerous other movies about the Great White, such as Zombie Shark, Santa Jaws, Meg, Deep Blue Sea and the list goes on.
White sharks (Carcharodon carcharias), also known as great white sharks, are the number one shark species that cause unprovoked shark attacks on humans. These sharks are the species made infamous by the brilliant movie "Jaws."
According to the International Shark Attack File, white sharks were responsible for only 314 unprovoked shark attacks from 1580–2015. Of these, 80 were fatal. For a span of over 400 years, that's less than one unprovoked white shark attack per year. That is nothing. More people die a year from coconuts hitting their head.
Although great whites aren't the largest shark, they are certainly one of the powerful. They have strong bodies that are about 10 to 15 feet long (3 to 4.6 meters) on average, and they can weigh up to about 4,200 pounds (1,905 kilograms). Their steel-gray back top color and white underside makes them one of the more easily recognizable large sharks.
White sharks generally eat marine mammals such as pinnipeds (seals), toothed whales, and occasionally sea turtles. They tend to stalk their prey with a surprise attack and release prey that is unpalatable. A white shark attack on a human, therefore, isn't always deadly since we aren’t appetizing flesh.
Tiger sharks are named for the dark, vertical stripes found mainly on their young. As these sharks mature, the lines begin to fade and almost disappear.
These large, blunt-nosed predators have earned a notorious reputation as man-eaters. They are second only to great whites in attacking people. But because they have a near completely undiscerning palate, they are not likely to swim away after biting a human, as great whites frequently do.
Bull sharks (Carcharhinus leucas) are large sharks that prefer shallow, murky waters that are less than 100 feet deep. These shallow, dark waters are perfect for shark attacks, as these habitats are where humans often swim or fish. The International Shark Attack File lists bull sharks as the species with the third-highest number of unprovoked shark attacks. From 1580–2010 there were 100 unprovoked bull shark attacks (27 fatal). Not terrible considering more people die from selfies each year.
Bull sharks grow to a length of about 11.5 feet (3.5 meters) and can weigh up to about 500 pounds (227 kilograms). On average, females are larger than males. Bull sharks have gray back and sides, a white underside, large first dorsal fin and pectoral fins, and small eyes for their size.
Bad eyesight is another reason why they may confuse humans with tastier prey. Although these sharks eat a wide variety of food, humans aren't really on bull sharks' list of preferred prey. Their ideal prey is usually fish (both bony fish as well as sharks and rays). They will also eat crustaceans, sea turtles, cetaceans (i.e., dolphins and whales), and squid.
The hammerhead sharks’ wide-set eyes give them a better visual range than most other sharks. By spreading their highly specialized sensory organs over their wide, mallet-shaped head, they can thoroughly and effectively scan the ocean for food.
One group of sensory organs is the ampullae of Lorenzini, which allows sharks to detect, among other things, the electrical fields created by prey animals. The hammerhead's increased ampullae sensitivity allows it to find its preferred meal, stingrays, which usually bury themselves under the sand.
Most hammerhead species are fairly small and are considered harmless to humans. However, the great hammerhead's enormous size and fierceness make it potentially dangerous, even though only a few attacks have been recorded.
Thresher sharks, Alopias vulpinus (Bonnaterre, 1788), aka Atlantic threshers, big-eye threshers, common threshers, fox sharks, grayfishes, green threshers, sea foxes, slashers, swingletails, swivel tails, thintail threshers, thrashers, whip-tailed sharks, and Zorro thresher sharks, are easily recognizable because of their long caudal (tail) fins which are equal to about half the total length of their body. This magnificent shark also has a very characteristic dorsal fin and pelvic fins.
These sharks’ teeth are small, curved, smooth and ferociously sharp. Their teeth are similarly shaped in both the upper and lower jaws. Thresher sharks’ color varies from metallic brown to blue on their dorsal (upper) sides and white on their ventral (under) sides. They range from 2.5-7.6 m in length (7.6 m max length for males, 5.5 m max length for females). Their max published weight is 348 kg.
Thresher sharks are not a threat to humans. There has only been one documented thresher shark attack on a person and it was provoked by the individual grabbing the poor shark’s tail. There have been four accounts of thresher sharks attacking boats, but these were sharks attacked by humans and who were fighting against capture. For the most part, thresher sharks are scared of humans and will even swim away the moment they see a diver.
Powerful, fast and aggressive, the Shortfin Mako has been blamed for many reported shark attacks on humans. In more than a few cases, human error is also to blame for the attacks as fishermen have been known to get injured after dragging hooked makos onto their boats.
The Shortfin Mako is believed to be the fastest shark, who is able to swim up to 20 miles per hour. Prior to attacks, the Shortfin Makos swim in figure eight patterns and approach their prey with mouths open. Sadly, the popularity of Mako meat in shark fin soup has reduced their population. The World Conservation Union has listed the Shortfin mako as "Near Threatened."
What Do You Do If a Shark Attacks? Here's How to Protect Yourself
While you are more likely to get electrocuted by Christmas lights than getting attacked by a shark, being chomped on by the sea predator's razor-sharp teeth is still a real fear held by many beachgoers. Swimming in a group and staying close to shore are two simple ways to avoid a shark attack. You can also discourage an attack by avoiding bright clothing or anything shiny. But what do you do if you actually encounter one of these frightening fish in the salty waters?
First of all, do not panic. Experts say sudden movements and splashing will attract the shark even more. If you spotted the animal and it spotted you, maintain eye contact. Sharks typically attempt to circle behind you to take a bite, so they will feel less comfortable if you keep an eye on them. Keep calm and slowly back away. If none of the above options are viable, you should fight back and focus your attacks on the shark's eyes and gills because these are a shark’s sensitive areas.
All man-versus-nature tropes, man-versus-shark movies, and man-versus-sharks-versus-other-creatures movies can reveal important truths about human nature and serve as fascinating, in-depth character studies. Unlike most other man-versus-nature tropes, they do it with a side of terrifying, razor-sharp teeth.
Sharks combine mankind’s desire to conquer nature with its fear of and fascination with the vast ocean. Even in this modern age, when we’ve been able to discover the depths of the seas, we still know surprisingly little about sharks. Jaws’ famous description of a shark’s "cold, dead eyes, like a doll’s eyes" in the film’s USS Indianapolis monologue (which was based on the real sinking of a US World War II Navy ship and subsequent shark attacks on its sailors) is still a testament on how little we know about these grand, magnificent, underwater animals.