They don't get cancer and never sleep: 12 shark myths you shouldn't believe

Myth 1. Sharks are bloodthirsty

We usually think of a shark as a ferocious, carnivorous monster straight out of the movie Jaws. Steven Spielberg - large white, or carcharadona. But in realityThe Massive Filter Feeding Shark You Ought to Know / Smithsonian Ocean Not all of these fish eat meat.

For example, whale sharks, basking sharks, and pelagic sharks feed on plankton.

These good-natured giants collect tiny crustaceans in wide-open mouths and do not pay attention to larger prey - just like whales.

But there is an even stranger case of shark pacifism.S. C. Leigh. Seagrass digestion by a notorious carnivore / Proceedings of the Royal Society B: Biological Sciences - small-headed hammerhead fish, or shovel shark. She cannot be considered a vegetarian, but still the diet of this creature consists of vegetable matter.

This Shark Eats Grass, and No One Knows Why / National Geographic more than half food. She swims along the bottom and eats crabs, shrimps, molluscs, and algae found there.

However, this is probably why the shovel shark is only a meter and a half long. If I ate meat, I would grow big and strong.

Myth 2. Sharks feel a drop of blood in the ocean for miles

Often on the Internet you can find the statement that sharks smell the blood that has fallen into the water for many kilometers, and how torpedoes rush to prey. Even a tiny scratch, just a single drop of blood, can supposedly attract them. But it is not so.

In general, the myth is not without foundation, because most sharks have a fairly good sense of smell. They have nostrils on their noses, which, however, are used solely for trapping odors, and not for breathing.

ResearchShark sensory mechanisms / Oxford University Press Blogstudies of olfactory receptors show that the best scent is not in the famous great white sharks, but in hammerhead fish. True, the latter often use their sense of smell to find the female, and not the prey.

However, the shark can really feel the blood in the water, but not at a distance of a kilometer.

Biologist Tricia Meredith of Florida Atlantic University foundT. L. Meredith. Olfactory morphology and physiology of elasmobranchs / Journal of Experimental Biologythat the smell of sharks is not something supernatural. The same tunas and stingrays have exactly the same sense of smell, but they do not have a reputation as top predators.

On average, a shark is able to feelShark Smell Myth Found Fishy/Inside Science one drop of blood in a billion drops of water. Approximately as much liquid contains an ordinary pool in the private sector. That is, if you cut your hand while swimming in it, a neighbor's shark that accidentally swims there will find you.

However, there are some doubts that these predators are strongly attracted human blood. Blogger and former NASA engineer Mark Robber conducted several experimentsShark Attack Test - Human Blood vs. Fishblood/YouTube in the Bahamas, luring predators with their own and cow's blood, fish oil and urine (well, what if sharks have strange tastes?).

As a result, it turned out that the subjects were much more interested in tuna fat than in the blood of mammals. Apparently, because sea cuisine is familiar to them, and they did not have the opportunity to taste a cow at the bottom of the sea.

Myth 3. All sharks are big

When thinking of sharks, most people think of that great white shark, or carcharadon, a predator from "Jaws». In fact, there are 400 different species in the world.Shark Species / Shark Research Institute these fish, and they are very different from each other - both in size, and habits, and appearance.

So, the great white shark reachesHow Big are Great White Sharks? / Smithsonian Ocean 6 meters in length, and its weight is under 1,900 kilograms. But there is an even bigger shark, under 20 meters, a whale shark. She, as we mentioned, feeds on plankton.

However, in the ocean you can find not only such giants, but also truly tiny predators that fit in your palm.

For example, the pygmy shark reachesL. J. v. Compagno. Sharks of the World length is only 26.5 centimeters. In addition to it, there is a spiny shark - about 28 centimeters and an Indian ribbon shark - about 24 centimeters. These are peaceful and shy fish that do not pose the slightest danger.

And the pygmy lantern shark can even glowDwarf Lantern Shark/Smithsonian Ocean with the help of photophores - special organs on the belly. This helps her to swim calmly and feed during the day: other fish, looking up, think that this sun glare floated by.

Myth 4. Sharks roll onto their back before biting

In fiction, one can find statements that sharks turn on their side or on their back before biting. So, in the novel "Twenty Thousand Leagues Under the Sea" this feature was used by the harpooner Ned Land to seize the moment to strike.

But this is a myth that could cost a shark hunter his life. Diver and photographer Valerie Taylor of the Royal Geographical Society of Australia filmed marine predators almost 60 consecutive years. She has watched them hunt whales and other marine mammals and says10 myths about sharks / Australian Geographicthat sharks don't have to roll over to bite.

The recommendationsG. A. Llano. Airmen Against the Sea: An Analysis of Sea Survival Experiences / Arctic, Desert, Tropic Information Center, Research Studies Institute on survival at sea for military pilots, specialists from the US Aviation University also argue that a shark can bite from almost any position. They advise those who have crashed and found themselves in the ocean not to rely on her imaginary clumsiness.

Myth 5. Sharks don't get cancer

In the collections of “incredible facts about nature”, it is quite common to find the statement that these marine predators never suffer from cancer.

But this, unfortunately for these fish and everyone who sympathizes with them, is not true. Scientists have recordedSharks Do Get Cancer: Tumor Found in Great White / Live Science the presence of cancerous tumors in at least 23 species of these predators, including the great white shark.

The myth that these cartilaginous fish are immune to cancer most likely originated from a 1983 study.

In it, scientists foundA. Lee. Shark Cartilage Contains Inhibitors of Tumor Angiogenesis / Science in shark cartilage, a substance that limits the development of blood vessels, and as a result, the growth of tumors. Journalists, as often happens, exaggerated a little and decided that since cartilage inhibits cancer, and sharks only have them instead of normal bones, it means that they do not have tumors. But it's not.

Myth 6. Shark fins are very useful

A fairly popular misconception is that different parts of sharks, such as their fins or cartilage, can heal various diseases, especially cancer. And also to prolong life, increase intelligence, improve potency and increase any parts of the body that you only want.

But this is also a myth. Whatever the proponents say alternative medicine, shark cartilage powder or fin soup does not cure cancer. That's what it saysSharks Do Get Cancer: Tumor Found in Great White / Live Science about this shark researcher.

Moreover, shark fins, which are largely composed of the same cartilage tissue, have an extremely low nutritional value. And eating them in general is unlikely to somehow improve well-being.

In addition, scientists from the University of Miami foundN. Hammerschlag. Cyanobacterial Neurotoxin BMAA and Mercury in Sharks / Toxinsthat the fins of some sharks contain significant amounts of mercury and a neurotoxin called BMAA.

Pisces are fine, they do not pay attention to such trifles. But a person can get degenerative diseases of the brain, such as Alzheimer's, Parkinson's and Lou Gehrig's diseases, or amyotrophic lateral sclerosis. And problems with the reproductive system for a snack.

Myth 7. Shark fins grow back when cut off

It is not true. Although some types of fish can indeed growH. G. Simon. Salamanders and fish can regenerate lost structures - why can't we? / BMC Biology lost tails and other body parts, sharks do not know how. Their fins are madeR. J. goss. Principles of Regeneration of cartilage and non-segmented horny rays called ceratotrichia, which are practically unable to regenerate. There are exceptions: for example, a whale shark canF. Womersley. Wound‑healing capabilities of whale sharks (Rhincodon typus) and implications for conservation management / Conservation Physiology heal even fairly severe wounds, but this is rare.

Therefore, when the fins are cut off, the shark is doomed to death from starvation or even suffocation, because its gills will not be able to work without movement. The poor fish will literally drown in their native habitat.

In general, it is better not to spend money on shark fin soup: it is cruel, pointless and even more so it is quite wasteful. good old perch ear much tastier and more nutritious.

Myth 8. Sharks can't freeze in place and never sleep

In fact, there is a lot of truth in this statement. Most sharks do need to move so that fresh water is always washing over their gills. But that doesn't mean they never sleep.

These fish, apparently, simply know how to swim.Do Sharks Sleep? / Britannica in a dream. At the same time, the shark's brain rests, and the spinal cord forces the body to move forward so that the respiratory system constantly receives oxygen from the water.

Greg Skomal, a biologist with the Massachusetts Department of Marine Fisheries, saysGreat White Shark Caught On Camera Napping For The First Time / NPRthat the great white shark is quite capable of sleeping, or at least dozing. In this state, she slowly swims forward with bulging eyes and an open mouth.

Moreover, some species, such as reef, carpet and lemon sharks, as well as the baleen nurse shark, have learnedDo Sharks Sleep? / Britannica draw water through the mouth through the gills and therefore are able to sleep, just laying down on the bottom. They are fine.

Myth 9. Sharks are solitary

This is not always the case: some of them are quite social animals. Lemon sharks, for example, constantly get together because it's easier to get food and safer together.

They know how to communicate and even teach in some way.D. M. P. Jacoby. Social behavior in sharks and rays: analysis, patterns and implications for conservation / Wiley Online Library each other. Seriously, a fish that has figured out how easy it is to get food can show it to their fellows. Little lemon sharks accompany adults and learn from them how to hunt and avoid other predators.

Even the most severe and frightening sharks, great whites, are able to feed together without interfering with each other.

These predators can even playIs the White Shark Intelligent? / ReefQuest Center for Shark Research with each other and socialize, as well as establish complex hierarchical orders in their groups.

Myth 10. Sharks are the main danger in the sea

Thanks to horror films, sharks are considered the most terrible sea cannibals. But statistics show that these fish do not justify the hopes placed on them.

According toShark myths and facts / The Australian MuseumAccording to the Australian Museum of Natural History, sharks bite people 100 times a year on average. And about 10 cases end fatally. Disease-carrying mosquitoes killThe deadliest animal in the world / Gates Notes more people per day than sharks have killed in the last 100 years in the world.

In fact, you are more likely to be killed by lightning than by this marine predator.

Sharks do not prey on humans or use them as a food source, so their attacks are very rare and random. For that matter, attacksShark myths and facts / The Australian Museumstray dogs are twice as likely to end in death. Yes, and meeting them is not an example easier.

But people are killingb. Worm. Global catches, exploitation rates, and rebuilding options for sharks / ScienceDirect 100 million sharks a year for food and medicine (which doesn't work anyway). So it is not we who should be afraid of them, but they should be afraid of us.

Myth 11. Sharks attack because they think people are seals

There is a myth that sharks kill bathers for one simple reason: they confuse them with large pinnipeds. And when the predator realizes that he made a mistake, he simply spits out the prey.

However, this is not true, although it sounds quite logical. Sharks often prey on seals and other marine mammals, but do not confuse humans with them. They use different tactics: when attacked, they resolutely tear and devour the animal immediately, and examine people carefully. Here's what they say about itGreat White Shark Attacks: Defanging the Myths / National Geographic specialists.

sharks biteGreat White Shark Attacks: Defanging the Myths / National Geographic people not because they seem to them to be seals. It's just their way of exploring the world. Instead of touching unfamiliar objects, as humans and monkeys do, these predators bite them. Although, if a great white shark bites a diver not out of anger, but out of curiosity, the victim will not feel better.

There is even such an expression - "research bite". Sharks constantly taste even inedible things with their teeth to understand what they are, because they cannot feel them. There are no handles.

Myth 12. When attacking a shark, you need to punch it in the nose

Just give the shark a powerful hook right in the nose, and the stunned predator will fall behind - such advice walks on social networks, periodically changing. It is also recommended to bite her yourself.

As the Eastern kung fu masters (or someone else) used to say: "If a fight is inevitable, strike first, brother."

That's just to beat the shark - one of the most stupidPunching A Shark In The Nose Is A Great Way To Become Fish Food / Lifehacker things you can do. These fish are much less sensitive to pain than mammals, so you are more likely to beat a bear than a shark. In addition, it is very difficult to hurt someone with a fist in the water, even if you are a boxing champion. After all, this environment is much denser than the good old air.

In addition, sharks tend to be apex predators in their habitatand therefore they are not shy. To attack first means to provoke a fish to attack back. And it is unlikely that a person will be able to emerge from this fight as a winner.

Also, the advice to play dead doesn't work with sharks, because they have an organ calledR. D. fields. Semiconductor gel in shark sense organs? /ScienceDirect ampoules of Lorenzini. It allows you to capture electric fields in the water - especially those that are created by the nervous system and muscles of living beings.

So to make a shark believe you're dead, you have to turn off your brain and spinal cord, and that's hard to do without actually dying. And these fish do not disdain carrion.

The only thing you can doHow Shark Attacks Work / HowStuffWorks when meeting with a sea predator - calmly swim away from her and get out of the water without provoking her to contact. And if she grabbed you and won't let go, it's better to put your hand in her gills. Chances are slim, but it might help.