With the light hand of Hollywood filmmakers and other creators of horror films, we are used to seeing sharks as cannibals, sinister monsters, capable of simply devilish cunning in the hunt for a person. But is it?
Amazing couch potatoes
Sharks of various species live almost everywhere in the World Ocean: from the eternal ice of the harsh Arctic to the kingdom of eternal cold and the penguins of Antarctica. But the largest number of them and the maximum diversity of species is noted in the tropical and subtropical zones. Probably, this is quite natural - more food, warmer water, better conditions for breeding. But here's what is unusual: sharks have mastered a huge column of water vertically, where their different species have settled from surface waters to breathtaking depths inaccessible to any super-submarines - up to 5 thousand meters! It is difficult to imagine how fish live and hunt at a depth of five kilometers, even in the tropics. However, ichthyologists suggest that this is far from the limit of the depths at which sharks live. Modern technology still does not allow researchers to look deeper - devices and metal bursting under the terrifying pressure of the water column cannot withstand. But the shark lives!
Another feature of these extraordinary fish will also certainly cause distrust and bewilderment: sharks are amazing couch potatoes, and each of them has its own "home" in the seas and oceans.
Over the course of decades, scientists have caught very young sharks, almost fry, in the waters of the Indian Ocean, off the southern shores of Africa and Australia. They were carefully measured, weighed and tagged with the shark's registration number and "address" on their dorsal fin, and then released. Wagging its tail, the fish immediately disappeared to get back to the researchers in … ten to fifteen years!
This allowed us to conclude that in any seas and oceans, sharks choose a certain area for life, highlighting a small area of water in it, which they consider their home. Unlike movie characters in horror films, real-life sharks of any kind never migrate far. And even if a cannibal suddenly appears among them, it costs nothing to track him down, because he, too, is constantly spinning around his house.
Therefore, if all sharks are destroyed in some area of the ocean, they will not appear there again soon. From other places, these fish do not come to the vacated territories, and by chance the survivors can restore the population size not earlier than in a few decades. The overwhelming majority of shark species reproduce slowly, and maturation for reproduction occurs in them almost like in humans, at about 15-18 years of age.
Promotional video:
There is no enmity with a person
So, the shark has a home from which it does not leave, and therefore, shark-prone areas remain so for centuries. There are no more than five such places in the World Ocean, and all the creepy stories about bloodthirsty predators attacking peaceful bathers and scuba divers in other places are pure fiction.
Where are the dangerous areas located? This is primarily the coast of Southeast Africa, Australia and Tasmania, most of the Caribbean, the Bahamas, the coast of Florida and Southern California. In the waters washing the shores of Russia and other CIS countries, as well as any European countries, there is no danger of being attacked by sharks! There is not a single place where species that can harm humans are found.
Of the 350 species of sharks that have settled in the oceans, only 28 species at least somehow and somehow at different times "guilty" before humanity. However, not all sharks are guilty of the fact that some individuals of their species once, maybe purely by accident, or defensively, caused harm to humans.
Ichthyologists know that among the numerous predatory tribe of "bloodthirsty" sharks, the overwhelming majority are completely harmless species. There are dwarf sharks - only up to 20-25 centimeters long. But, of course, there are also giants, up to 20 meters long and weighing twenty tons! But they cannot attack anyone, as they feed only on … plankton!
Over hundreds of years of observation and collection of statistics on shark attacks on humans, an amazing detail has emerged - a shark attacks a person only at water temperatures from 18 to 20 degrees Celsius, only in the summer and only when it is extremely hungry! But deaths from shark attacks average between 30 and 50 percent. That is, the attacked person has a real chance of survival.
Meticulous American scientists, lovers of counting everything and everyone, have established that over the past 300 years, 800 cases of shark attacks on humans have been recorded on all seas and oceans - an average of two and a half cases per year.
Moreover, as soon as scuba gear appeared and the passion for spearfishing began, the frequency of attacks increased significantly. Apparently, the careless, careless, and even somewhat too impudent behavior of people in the underwater world that does not belong to them to a large extent provoked a collision with sharks.
Recently, up to four shark attacks a year have been reported off the coast of the United States, and three attacks have occurred on the touristy beaches of Southern California over the past decade. Off the coast of Africa, where tourists and scuba divers are much less, only two shark attacks were recorded. Naturally, every such case causes a huge public outcry, which is based on primitive fear! People are decisively demanding the destruction of all sharks, fence the beaches with concrete walls, steel nets, etc.
But according to the calculations of the same American scientists, over the same period, more than a thousand three hundred people drowned out of their own carelessness, about fifty-five thousand people perished annually under the wheels of cars because of their carelessness, and up to two million were injured! Yet it was precisely on every encounter of a man with a shark that radio, print and television made a fierce noise.
Legends of gluttony
In many films and books, you can find many spectacular stories about the incredible gluttony of sharks.
Readers expecting to hear a chilling story will be disappointed: the main food of sharks is not people, but small and medium-sized fish, plankton and squid.
Some sharks find food near the surface of the water, others catch bottom fish, octopuses or crustaceans, and still others eat sea turtles and shell mollusks.
Moreover, the strong shells of these marine life sharks click like nuts. If a shark's tooth falls out or breaks, a new, healthy and strong one grows in its place - a very enviable quality for a person!
Of course, the shark should not be idealized: a predator is a predator. They actively hunt seals and engage in cannibalism, eating sharks of other species and even their own kind, without a twinge of conscience eating their brothers and sisters. The shark behaves like a wolf in existence. She avoids attacking herds of dolphins - they will simply kill her! - but he will not miss the chance to hunt for a weakened or sick individual. They can also attack such large fish as tuna, but considering that its speed is about 100 km per hour, sharks do not hunt it often. The best characterizes the nutrition of sharks by keeping them in aquariums. Usually, the weight of the food eaten is related to the weight of the animal. So, for example, an insectivorous bird eats three hundred times its own weight per year, and a shrew mouse - six hundred!The pike we all know eats eight times its body weight a year. Compared to them, sharks are generally small! One three-meter sand shark lived in captivity for about ten years, and the ichthyolongs had time to study its diet. So, a year she ate from 70 to 100 kg of fish, which was 0.6 kg of her body weight. In principle, a fairly large shark, three meters long and weighing more than one and a half centners, eats about 250 grams of fish per day to maintain normal life! And she has enough.eats about 250 grams of fish per day to maintain normal functioning! And she has enough.eats about 250 grams of fish per day to maintain normal functioning! And she has enough.
Unhappy creatures
This is what some ichthyologists call sharks. Why? But because they live hard in the seas and oceans. As soon as the shark is born, it is immediately doomed to perpetual motion until death and, practically without stopping, constantly swims from the first to the last minute of its existence: night and day, day and night, never falling asleep and not knowing rest!
The fact is that a shark cannot breathe normally without moving - it does not have the appropriate muscles for this, like other fish, which can forcibly drive water with dissolved oxygen through the gills, even while standing in one place. If the shark stops, then in less than an hour it will die from asphyxiation - suffocation! Previously, they did not know this, and therefore the sharks died in captivity, but now circular pools are being built for them, where they can wind round and round day and night.
V. Antonov