The real reasons that sharks attack humans

She was sitting astride her surfboard, enjoying the warmth of the sun as she and her cousin waited for the next wave in the idyllic Bay of Tasmania.

Behind them, the bright white sand beach was largely deserted. The surf day had been good until then.

The sudden shadow that appeared underneath forced Mighall to instinctively lift his feet: balls of seaweed often broke against the rocks and floated in the waves.

"They are very slimy, I hated to touch them," he says.

But then something grabbed his leg. "At first, it did not hurt me, it was as if something had caught me gently, and then I was in the water," says Mighall.

For those who attended what happened, however, everything was sweet.

The water around Mighall exploded when a five-meter-long white shark hung his right leg, lifted it from the surfboard and shook it in the air before to disappear under the water.

"It took me a few seconds to realize that it was a shark," he says.

"When I came out of the water, I was on my back but I had my leg in the mouth.All I could see, was my black leg with the combination , his teeth, the pink gum and the dark part under his nose.I was having a nightmare and I was constantly trying to open my eyes. "

Syb Mundy, Mighall's 33-year-old cousin, a few meters away from her, ran and began to hit the shark on the side of her head.

The shark moved away from him and, while drowning, released Mighall, sinking his surfboard, which was still tied by a rope to his leg.

The board in the mouth, the shark pulled Mighall under the water for the second time. Moments later, he appeared again on the surface with the damaged board.

Mundy caught his cousin, put him on his back and rowed frantically toward the shore.

"The shark surrounded us under the water," says Mighall. "Then this wave came and Syb said," We have to catch it, it will save our lives. "I only touched the water because I was terrified, but he paddled and the wave took us to the coast.

The shark came with us to the beach. We could see his fin while riding the same wave. "

Fortunately for Mighall, among the few people on the beach who attended what had happened that day, there was a doctor and a nurse. He received essential first aid pending the arrival of an ambulance.

More than 10 years later, he still has deep scars on his leg that outline the shark's mouth and his right leg is weaker than the left.

Mighall was one of the 83 people in the world who had been unprovoked by sharks in 2009, a figure that has remained at the same level over the last decade.

The average number of unprovoked attacks between 2013 and 2017, for example, was 84. However, recent research indicates that shark attacks in some parts of the world appear to be increasing.

The eastern United States and southern Australia have seen shark attack rates almost double over the last 20 years, while Hawaii has also seen a sharp increase . But why?

Large populations

"Shark bites are strongly correlated to the number of people and the amount of sharks in the water at the same time," said Gavin Naylor, director of the Florida Shark Research Program, which maintains 39, international archive of attacks. sharks

"The more sharks and people in the same place, the more likely they are to be found."

This sounds obvious, but when you take a closer look at where the attacks are taking place, you have clues as to what might happen.

Significant human populations along the south coast of Australia and the east coast of the United States. They imply that there is a large number of people who like water in these places.

But in southern Australia, the number of sea lions on the coast has also increased and is the favorite prey of white sharks in the region.

Similarly, seal populations on Cape Cod on the Mbadachusetts coast in the United States. In the United States, they have recovered in recent years, largely thanks to the protection of the Marine Mammal Act introduced in 1972.

This has resulted in a greater number of white sharks in the area, also during the hot summer months, seeking to feast on seals that leave to enjoy the beaches.

Unfortunately, last fall, Mbadachusetts suffered its first deadly attack by sharks in 82 years, and an increasing number of shark sightings resulted in beach closures.

But according to the scientists who study them, there is really no evidence that sharks actively hunt humans.

White sharks in the North Atlantic, for example, exhibit patterns of seasonal movements, migrating thousands of kilometers to warmer waters further south during the winter months.

Some mature adults venture into the open sea for months, traveling tens of thousands of kilometers and diving to depths of 1,000 meters in search of prey.

"We look like little helpless sausages floating in the water," says Naylor. But even though it's such an easy meal, sharks do not really care about the hunt for humans.

"They usually ignore people, I think if people knew how often they are in the water of sharks, they would probably be surprised."

However, Naylor believes that official statistics on shark attacks probably underestimate the actual numbers.

Most reports come from heavily populated developed countries and very active media. Attacks on remote islands or less developed communities are probably not reported.

66 attacks

Examining statistics on the number of shark attacks last year may reveal some fascinating trends.

Last year, there were only 66 confirmed unprovoked attacks, a decrease of about 20% from previous years.

According to the International Shark Attack Archive, only four of these attacks were fatal, although another database of shark attacks records seven deaths.

Until now, in 2019, there have been four fatal attacks of sharks.

The reason for this fall was attributed to a sharp decrease in the number of black tip sharks.

These sharks are responsible for many attacks in the southeastern United States. UU., Migrating along the coast of Florida due to the rising sea temperature that has pushed its dams to disperse further.

The results highlight one of the main challenges in understanding why sharks bite humans.

There are dozens of different species responsible for the bites, each with its own behavior, hunting strategies, prey and preferred habitat, but in many cases the species may be misidentified or not identified at all.

Most unprovoked attacks against humans in which the species is identified include three main authors: the great white shark, the tiger and the bull.

However, white sharks, the species of the famous film demonized in Hollywood since then, is not only a different species, but a taxonomic category completely different from the other two.

"There are 350 species of sharks and a lot of diversity, you can not put them together," says Blake Chapman, a marine biologist who has studied the sensory systems of sharks and recently wrote a book about shark attacks on humans.

Bull sharks, for example, tend to hunt in shallow, troubled waters, where they rely less on vision than on their sense of smell and electroreception, allowing them to detect tiny electric fields produced by their prey.

"White sharks, which often hunt in very clear waters, use their vision a lot more and their eyesight is much better," Chapman said.

Chapman believes that there may be a complex set of reasons why unprovoked attacks against humans seem to have increased in recent decades.

In addition to increasing human populations along the coast, habitat destruction, water quality, changes in water quality, climate change and changes in dam distribution are driving sharks. to gather more and more critical points around the world.

In 1992, for example, there was a sudden series of shark bites off the coast of Recife, Brazil, an area that did not experience any spontaneous attack in the previous decade.

Chapman believes that the construction of heavy commercial ports in the area has damaged large areas of reefs and mangroves, potentially moving species such as bull sharks, which have moved to new areas such as Recife in search of A prey.

Attacks on Reunion

Reunion Island, in the Indian Ocean, famous for its beautiful pristine marine habitats, has seen a surge in tourism, but in recent years it has also undergone a growing number of bull sharks attacks and tigers living in the surrounding waters. .

Since 2011, there have been 11 deadly attacks in Reunion, mainly against surfers. Investigators have discovered that about two-thirds of the attacks in Reunion took place in murky waters and by waves of more than two meters, the preferred environment of bull sharks, which would be responsible for most attacks.

Naylor thinks that in most cases shark bites are due to mistakes.

"If these animals pursue bait fish, the flash of a person's white foot could make them loose," he says. "When you have a big animal like a tiger or a white shark, which moves quickly, a bite is more likely to be fatal."

Great white sharks usually attack from below, causing a mbadive catastrophic bite. In some cases, they retreat while their prey dies bleeding before returning to eat.

"A predatory white shark is a show," says Greg Skomal, a marine biologist with the Mbadachusetts Marine Fisheries Division, who has been tagging and tracking great white sharks since 2009.

He should know that since last year, when he was trying to tag a shark above the bow of a search boat, a great white shark appeared just below him, his mouth open.

"It gave me an idea of ​​how a seal feels," he says. "I have observed this behavior over and over over the years, most of the time we have put a camera in the water and the sharks are totally accommodating," he says.

"We had to do it thousands of times, but on a handful of occasions, they immediately attack, breaking the pole and the camera.It's like they're in an acute predator state." where their senses are fixed on any kind of stimulus. "

"I wonder if these attacks against people who are not just investigators are the result of a person who is in the wrong place at the wrong time with a shark in this kind of sharp state."

But for every attack against a person, there is an equal number of stories of people who have managed to approach these giant predators without suffering damage.

Take the example of Ocean Ramsey, who swam alongside a huge white shark more than six feet long off the coast of Hawaii and who made the headlines in the whole world.

Forensic methods

Skomal and his colleagues are now using new high-resolution tags that can provide researchers with minute-by-minute and second-to-second data on shark activities.

He hopes this can help answer questions about the behavior of these animals, as well as where and how they breed. In the end, it could also help us explain the underlying reasons for the attacks on humans, he argues.

Some investigators are turning to forensic methods to try to understand the reasons for attacks, developing techniques for using DNA and bites to identify species, while others are examining video images of attacks and compare them to lesions to understand them. Better what happened.

But whatever the reasons for attacking humans, the risks are still very minimal. In Australia, the number of shark attacks is in the order of 0.5 per million people, while in the United States. UU. It's less than 0.2 attack per million.

In 2018, the US figures. UU. they dropped to about 0.08 attack per million, while in Australia they increased to 0.8 attack per million inhabitants.

These data do not take into account the much smaller number of people who actually use water, nor the even smaller numbers of people swimming in waters populated by dangerous sharks. But these statistics, ridiculous as they are, they rebadure, do not they forget our fear of sharks.

"Fear played a very important role in our evolution," adds Chapman.

Focusing on the risks that sharks pose to us also diverts our attention away from the much greater threat we pose to their survival due to overfishing and man-made climate change.

Some estimates suggest that the number of sharks in Australian waters, for example, would have decreased between 75 and 92%.

But for those who are scared and want to know how to protect themselves from a shark, some advise that when a shark is biting, it must be knocked to the gills or to the eyes.

It is known that swimming in groups and staying near the coast reduces the risk of attacks. Wearing dark clothing and avoiding wearing jewelry can also help reduce the risk of attracting the attention of a shark.

"Shark attacks cause a lot of personal losses, but the impact they can have on the community in general is often not taken into account," says Dave Pearson, one of the most founders of Bite Club, which provides support to survivors of shark attacks. .

He himself was attacked by a bull shark while he overfished eight years ago in southwestern Australia. He almost lost his arm when the animal crushed him, bit him to the forearm and carried him under the water.

"After my attack, many of my friends did not return to the water for a long time," he says. "The fear spreads very quickly."

During a recent visit to Ballina, a surf spot in New South Wales, Australia, found what a shark attack can do for a city. The region suffered a series of attacks, including two deaths against surfers in 2015.

"I was there watching the arrival of those perfect waves, but there was not a single person in the water," he says.

A similar case occurs in Reunion, where local authorities have banned surfing and swimming in water at certain times of the year, for fear of further shark attacks.

As a result, the number of human bites has been reduced, but this has also affected the tourism industry.

Psychological scars

Despite the fear and economic costs of shark attacks, Hannah Mighall does not want these animals to be slaughtered or those diverted to areas used by humans to be killed.

The personal damage caused by the attack of which she was victim however lasted. Although he surfed again six months after his attack and that he "became crazy about sharks", covering the walls of his bedroom with pictures of these animals, he claims that his pbadion for surfing & surfing Is gradually faded.

"He was fine and suddenly he had a strange sensation and started looking around," he explains. "I had never had this before, I was a baby aquatic and I liked the water.Now I'm scared.I thought the sharks were great, but now they scare me, even though I always respect them. "

He has no more shark displays and his enjoyment of the sea has disappeared. He prefers to swim or kayak in the river. But he still has a nightmare with sharks.

Pearson says that it is a common problem among victims of shark attacks. "Many of them never heal completely and psychological scars can be even bigger than physical scars," he says.

Mighall still has the surfboard that he used on the day of the attack, he misses a marked chunk of teeth. Like the scars on his leg, this is reminiscent of what can happen on the rare occasions when sharks choose to attack humans who deviate from their fields.

Both give them the right to fear these animals. For those who fear them without having a meeting so close, he has good advice. "If you are afraid, you can always stay out of the water."

BBC