With their dark eyes, sharp teeth and fearsome reputation, all sharks are ruthless killers… aren’t they?
Sharks have occupied the role of villain in the movies ever since the first Jaws film terrified audiences around the world. Sharks are undeniably intimidating creatures, but they don’t deserve the fear and hatred the silver screen has generated. With some help from The Deep, we’ve busted some of the top shark myths you’ll come across in the cinema.
Sharks target humans
Thanks to the movies, sharks are thought of as ruthless killers targeting any human foolish enough to get in the water. You might find it reassuring to know just a few of over 400 species are considered dangerous, and you’re far more likely to be killed by a cow than a shark. There are around 16 shark attacks each year in America, but just one fatality every two years.
The Shark Trust believe the ‘monster’ image is not one sharks deserve. Conservation officer Cat Gordon says, “Sharks need to be treated with respect, like any wild animal. Even a typically ‘harmless’ filter feeding shark like a basking shark is capable of breaching clean out of the water, so it’s wise not to get too close.
“When humans are bitten, these incidents are inevitably high profile due to their traumatic nature, but they are usually the result of an exploratory bite to see if the target would be suitable prey. The number of reported shark bites is relative to the number of people entering the marine environment each year, with increased popularity of ocean-based recreational pursuits and technology allowing people to remain in the water for longer”.
Sharks can swim backwards
Jaws 3-D, the third instalment in the Jaws franchise, centres on a pair of great whites that sneak into SeaWorld. In one sequence, the larger shark backs out of a filtration pipe at enough speed to break through the grille trapping it there.
That really should have been the end of the story for the man-eating shark, because sharks can’t swim in reverse. They’re propelled by their tails and use their pectoral fins for balance and turning, and their anatomy simply doesn’t allow them to go in any direction other than ahead.
While many sharks are able to pump oxygen-rich water through their bodies using their pharynxes as they lie on the seabed, some species – including the great white – lack this ability and have to swim forward constantly to keep water flowing over their gills.
Sharks seek revenge
The great white shark in Jaws: The Revenge is so determined to wreak havoc on the Brody family that it follows them from the northeast coast of America to the Bahamas. As perfect as it would be for filmmakers, sharks aren’t really capable of holding grudges – their main motivation is always just getting enough to eat. Sharks are intelligent fish, and it’s been shown that they’re able to learn. When tour boats repeatedly feed them they begin to associate people with food, but vengeance doesn’t enter their minds.
If sharks were capable of revenge, it would arguably be justified; we’re much more dangerous to them than they are to us. While they kill less than one person a year, in the same amount of time 100 million sharks are killed by humans. Many of these are victims of the shark fin trade, their fins cut off for soup and traditional medicine and their bodies thrown back into the sea, but others are killed in the hope that it will make the oceans safer. Not long after the release of Jaws shark hunting became popular, and in 2014 the Australian Government began a controversial (and short-lived) cull of sharks around the west coast.
Sharks live for thousands of years
Investigating the deaths of the great white’s victims in Jaws, police chief Martin Brody reads that sharks can live for 2,000 to 3,000 years. He should probably have checked a different book, because no shark species has a lifespan even close to that. Although it’s been found to live longer than previously thought, the great white shark’s average life is still a modest 70 years long.
It may not meet movie expectations, but one shark does claim the record for longest-living vertebrate on the planet. Greenland sharks, residents of the cold waters around the Arctic Circle, have been found with up to 400 years already behind them. It’s thought that their large size combined with the low temperatures they live in result in a slow metabolism and a drastically reduced ageing rate. These sharks are still something of a mystery; their long lives were only discovered a few years ago, and little is known about what they do with their centuries in the sea.
Sharks can smell a drop of human blood in the ocean
A swimmer scratches their hand and a single drop of blood falls into the water. A few bars of ominous music later, a hungry shark appears to claim their free meal. It’s a classic image, but is a shark’s sense of smell really that good?
Not quite, according to the Shark Trust. “Sharks have a highly complex and acute sense of smell. Their highly evolved olfactory organs allow them to detect the blood of potential prey, pheromones from a potential mate or the scent of a predator from a great distance – one part of blood to one million parts of water. That’s equal to one teaspoon in an average-sized swimming pool,” adds Cat.
For blood to reach the shark’s olfactory system it first has to dissolve and travel through the water, which would take more than seconds. As we’re not their normal prey, sharks following the scent of blood aren’t targeting humans – they’re either investigating or, in the case of ocean whitetips and silky sharks, following their instinct to look for thrashing wounded animals.