In the vast ocean, sharks known as "sea overlord" are all over the world.

There are many kinds of sharks, including at least 350 species in the world's oceans and more than 70 species in the Sea of China. Most sharks are good for human beings. Sharks do have a reputation for eating people, but not all sharks eat people. Only more than 30 kinds of sharks attack humans and ships for no reason.

Sharks, known as mako sharks, mako sharks and sand fish in ancient times, are giants in the ocean, so they are called "wolves in the sea". Sharks eat meat so fiercely that even whales, the "king of the sea", have to avoid it.

Its greedy and ferocious nature left a terrible image for people when feeding bait. Therefore, when it comes to sharks, people often feel scared when they say it.

Sharks are better at catching food than tigers. They can make full use of their unique sense of smell to detect the direction and position of food, while tigers only use their eyes and nose to find food. Shark's nostrils are located in front of the ventral mouth of the head, and some nostrils have nose-mouth grooves, and the nose-mouth angles are connected. The folds of olfactory sac increase the contact area with the external environment.

According to the measurement, the total area of the olfactory membrane of a shark with a length of 1 meter can reach 4842 square centimeters, so the shark's sense of smell is very sensitive. It can smell blood several kilometers away. Once animals in the sea are injured, they are often attacked by sharks and die. Sharks usually only eat live food, and sometimes they eat carrion. The food is mainly fish.

Dolphins, waterfowl, turtles, crabs and various fish were found in the stomach of ferret sharks. A very large sea lion was taken out of the stomach of a man-eating shark; The food of hammerhead sharks is fish and crabs; The diet of nurse sharks and star sharks is mainly small fish, shellfish and crustaceans. When sharks are looking for food, there are usually one or more sharks swimming in the water. Once they find the target, they will quickly attack and swallow it.

Especially when a large number of baits fall into the water in a ship or plane crash, they will flock, and sharks in a state of excitement and frenzy will eat almost everything they encounter, and even kill each other for food. Sharks belong to cartilaginous fish and have no swim bladder. The regulation of ups and downs mainly depends on its big liver.

For example, a 3.5-meter-long great white shark found in the southern hemisphere has a liver weighing 30 kilograms. Scientists' research shows that shark's liver depends on the increase or decrease of diacylglycerol ether, which is much lighter than ordinary triglyceride, to adjust buoyancy.

Although sharks are fierce and disgusting, they are all treasures and important economic fish. Shark's liver is particularly large and rich in vitamins A and D, which is an important raw material for making cod liver oil. Shark skin can be tanned, and its fin is a treasure in seafood-shark fin.

Sharks can also be used as medicine. According to the research of scientists, sharks seldom get cancer. Even if the most terrible cancer cells are transplanted into sharks, sharks are still safe and sound.

Because its cells secrete a substance, which can not only inhibit cancer substances, but also reverse cancer substances. Strange sense of smell According to fossil investigation and scientists' calculations, sharks lived on the ground for about 65.438+0.8 billion years. They existed as early as 300 million years ago, and their appearance has not changed much so far, which shows that they have strong viability.

However, its character is extremely fierce. No wonder people have great prejudice against it and think it is so primitive and stupid. In fact, sharks not only have a highly developed brain, but also can store information in the center of the brain with the help of electromagnetic fields and send information directly to the motor nervous system. And rely on a keen sense of smell to maintain all life activities. So the sense of smell is more important and mysterious to sharks.

Sharks are particularly sensitive to the smell of seawater, especially to the smell of blood, low-frequency vibration or a small amount of bleeding caused by irregular swimming of injured fish, which can attract them far away, even exceeding the sense of smell of land dogs. You can smell the fishy smell of flesh and blood with the concentration of 1ppm (one in a million) in the water.

Japanese scientists have found that even if only 1 g amino acid is dissolved in 1 10,000 tons of seawater, sharks can detect the smell and gather together. For example, after giving birth, a female shark can swim back to her birthplace with the smell even if she roams thousands of miles in the sea.

A shark with a length of 1 meter has dense olfactory nerve endings of 4,842 square centimeters, such as a man-eating shark with a length of 5-7 meters. Its sensitive sense of smell can smell the blood of injured people and marine animals several kilometers away. More interestingly, sharks can also distinguish their children according to various smells, distinguish enemies from friends, maintain group contact, and meet male and female sharks to lay eggs and sperm.

Because sharks have a keen sense of smell, they can easily smell their own fear or disgust. Sharks can also detect the smell of L- hydroxyalanine, a human secretion with a content of 80 billion in seawater.

It is said that there was once a professional shark catcher. In the later shark catching, the shark never caught his hook again, but other fishermen in the same fishing ground caught more sharks instead. Why are sharks afraid of this shark catcher? According to the research of ichthyologists, shark catchers once suffered from skin diseases, so the fingerprints left on fishing rods contain this L- hydroxyalanine.

When sharks smell this smell, they will naturally stay away from him, which is why they don't take the bait. Unique teeth It is known that sharks have many unique ecology in marine life.

Besides a keen sense of smell, sharks rarely get sick and die. The tooth structure of sharks is another unique ecology. Anyone who is familiar with sharks knows that its teeth are like a sharp knife, which can easily bite off a cable the thickness of a finger.

Such as the devil shark, has a long, pointed nose and sharp teeth. The teeth of different kinds of sharks are almost different in size, shape and function.

Therefore, ichthyologists can judge which order, genus and family sharks belong to only by the shape and size of their teeth. Surprisingly, shark's teeth are not fixed in a row like other animals in the ocean, but there are 5-6 rows. Except for the outermost row of teeth, the other rows are "supine", just like the tiles on the roof. Once the outermost tooth falls off, the inner row of teeth will move forward immediately to make up for the hole position that replaces the fallen tooth.

At the same time, the larger teeth of sharks will constantly replace the smaller teeth during their growth. Therefore, sharks are one.

Is shark meat edible? Why can't shark meat be eaten

Eating shark meat will not only be harmful to the human body, but also help the human body to supplement a variety of nutrients. However, the taste of shark meat is rarely accepted by people. It belongs to cartilaginous fish such as red ray (Laoban fish), and its meat contains a lot of urea, so it will give off the smell of urine. But if you cook well, shark meat can still be cooked very delicious.

Shark meat is a very precious fish in life. Although the shark is fierce, it has high nutritional value to human body. Shark meat is rich in protein and nutrients, which is very beneficial to human body and can also achieve nourishing effect. Shark meat has a unique taste and there are many ways to do it.

Benefits of eating shark meat:

1. From the point of view of traditional Chinese medicine, shark meat has the effects of benefiting qi and nourishing yin, tonifying deficiency and strengthening waist, promoting diuresis and resolving phlegm.

2. Modern scientific research has found that sharks are the only animals that don't get cancer, and shark products have a certain inhibitory effect on cancer cells.

3. In addition to cancer, shark meat can obviously improve many inflammatory and autoimmune diseases accompanied by abnormal vascular proliferation, such as rheumatoid arthritis, psoriasis, lupus erythematosus and so on.

4. Shark's fin contains many kinds of protein, such as cartilage mucin, collagen, chondrosclerosis protein, etc., and also contains lipid-lowering, anti-arteriosclerosis and anticoagulant components. The rich collagen in shark fin is beneficial to nourish and soften the skin mucosa, and it is a good beauty food.

It is worth mentioning that shark liver is also the main source of extracting cod liver oil. As we all know, cod liver oil has the functions of strengthening physique, promoting development, strengthening brain and improving intelligence, and helping calcium and phosphorus absorption, and can be used to supplement vitamins A, D and DHA in infants and children during their growth period. At the same time, it can be used to prevent dry eye, night blindness and rickets.

Can sharks eat?

The answer is yes, not only will it not die, but it will also be good for your health. Fish is one of the edible marine fish, and now most of them are farmed sharks in the domestic market. Sharks are rare aquatic products on the table, but their shark fins and lips have long been famous. Shark's fin is fresh, tender and delicious, and it is a precious food as famous as bird's nest and bear's paw. Shark fin is very expensive because it is rare, but it is not particularly nutritious. Perhaps compared with other diets, it is a symbol of luxury and wealth.

Chinese medicine believes that shark meat has the effects of benefiting qi and nourishing yin, tonifying deficiency and strengthening waist, promoting blood circulation and resolving phlegm. Scientists have found that among all animals, sharks are the only animals that won't get cancer. Many studies have also found that shark products do have a certain inhibitory effect on cancer patients. In addition to cancer, it can also obviously improve many inflammatory and autoimmune diseases accompanied by abnormal vascular proliferation, such as rheumatoid arthritis, psoriasis, lupus erythematosus and so on. Shark fin contains many kinds of protein, such as cartilage mucin, collagen and chondrosclerosis protein. It also contains blood lipid lowering, antiatherosclerosis and anticoagulant components. If you have coronary heart disease, taking some shark fin powder every day can play a preventive role. Shark fin is rich in collagen, which is beneficial to nourish and soften skin and mucosa, and is a good beauty food. Shark liver is the main source of extracting cod liver oil. Cod liver oil can strengthen physique, promote development, strengthen brain and improve intelligence, help calcium and phosphorus absorption and increase resistance to infectious diseases. It is used to supplement vitamins A, D and DHA for infants and children during their growth period. It can also prevent dry eye, night blindness and rickets. This product is also suitable for pregnant women and lactating mothers to supplement vitamins A, D and DHA, which is beneficial to the healthy growth and brain development of fetuses and babies.

Special tips

Dried shark's fin contains 83.5% protein, but due to the lack of tryptophan, it belongs to incomplete protein, so it can't play a role in human body after eating it. Generally, it is poultry, shrimp, crab and so on. Both of them contain more tryptophan, which can not only give them delicious taste, but also make up for the deficiency of tryptophan. The production process of dried shark fin is extremely responsible and takes a long time, so it is not suitable for soaking hair at home. Don't take cod liver oil in large doses or for a long time, otherwise it will cause poisoning. But now there are fewer and fewer sharks. We should protect them, so we should not eat them.

Do sharks eat people?

Someone has done a survey in Australia to see which words can arouse people's strong shock most.

Therefore, the words "murder", "death", "infatuation" and "poisoning" were put forward. Surprisingly, the name of a marine animal-shark-finally topped the list.

Due to the release of the movie Jaws, many people were afraid to swim in the sea that summer, but stayed on the shore to bask in the sun. In fact, the fear of shark attacks is far from the danger itself.

According to statistics, among every 5 million swimmers, only 1 person is likely to be injured by sharks. However, the horror legend about sharks eating people is still widely circulated.

In order to find out the truth of shark attack on human beings, American scientist David Baldridge consulted the archives of shark attack on human beings of the United States Navy, collected 165 and 438+065 records of shark injuries, and drew some unusual conclusions in view of people's fear of sharks. First of all, "sharks attack humans about 100 times a year, and most of the consequences are very serious."

This statement is wrong. According to California records, only 32 people were attacked by sharks from 1980 to 1990.

In recent years, there are only 28 recorded incidents of shark wounding in the world every year, and the mortality rate is gradually decreasing, from 46% in 1940 to 10%~20% at present. Secondly, "sharks hurt people because of hunger."

In this regard, Baldrich believes that only a few sharks hurt people because of hunger, while most sharks just bite and leave when attacking people. How to explain this behavior? He thinks that if it is in turbid seawater, it may just be a misunderstanding.

Another more credible explanation is that sharks regard their victims as threats. Perhaps the swimmer inadvertently disturbed the shark's courtship, invaded its territory, or cut off its escape route, so this person was naturally attacked by the shark.

It should be admitted that the great white shark is indeed the scariest and bloodiest of all sharks. It goes without saying that it likes eating mammals more than other sharks, such as whales and seals, walruses and sea lions. If you put on a black bathing suit and go swimming in the waters where great white sharks are infested, it is simply stupid.

Because you look like a seal and swim in the shark's "restaurant", isn't this a dish for the shark's dinner? So do sharks really like to eat people? Leonard Kang Paguenaud, a biologist at the University of San Francisco, said, "Most sharks are small and harmless to people." In 1980s, scientists discovered a giant shark, which was named "Devil Shark" at that time. This giant shark's mouth is enough to swallow a person in one bite. Fortunately, it only eats plankton.

Although it is true that a few big sharks attack humans, they do not take humans as their main prey. The reason why they attack people is probably that divers or people swimming in shallow waters are mistaken for prey such as seals and walruses.

Generally speaking, the great white shark, which ranks first in the list of man-eating sharks, is not very interested in people. Great white sharks are famous for their large appetite among more than 300 kinds of sharks. It is extremely aggressive and can eat almost anything it swallows, including the human body.

However, it often happens that the great white shark will suddenly let go when it bites down for the first time. What is the reason? Marine biologists who study shark food in the United States believe that sharks don't like human flesh, but prefer to eat fat.

The reason may be that human flesh is too salty and not fat enough. Because of this, the great white shark will never miss every opportunity to hunt dolphins, sea lions and even whales.

Thin prey, such as seabirds or sea otters, are generally "disdainful". It is because of the habit of eating greasy food that this can explain why great white sharks bite people and then abandon them at some point.

Because of its high calories, greasy food is of great significance to great white sharks, because fat is more important than muscle in energy. In the video of sharks killing whales, it is obvious that they only eat blubber.

People also found 500 dead seals off the coast of Canada. Only the bones of the seal are left, and the layer of fat on it is gone. 1935, a great tiger shark was captured alive and exhibited by tourists in an aquarium in Australia.

Suddenly, a human arm was spit out from the tiger shark's mouth, which suddenly scared the tourists! But after forensic identification, the arm was not bitten by a shark from the human body. The police thought of a missing case that happened two weeks ago and quickly solved this strange case.

It turned out that an amateur boxer participated in a cabal, was killed by his accomplices after defeat, dismembered and thrown into the sea to disappear, and was swallowed by tiger sharks. As soon as the tiger shark swallowed the human arm, it was captured. Just because it was not interested in human flesh, it spit it out.

This incident shows that sharks really don't eat people. The oceanographer's final conclusion is that in fact, ordinary people are less likely to encounter sharks and are not attacked by them.

In the United States, about 25 people die from bee stings every year, 150 ~200 people die from lightning strikes, and 140 people die from traffic accidents every day. In contrast, there may be no more than 30 shark injuries per year in the world.

It can be seen that the threat of sharks to human beings is relatively small, and the extreme fear of sharks is completely unnecessary. According to the traditional theory, due to overfishing, sharks have to enter inland waters to find food, which will lead sharks to attack humans.

But the latest research results show that this is not the case. American scientists believe that many shark attacks on humans are caused by human invasion of shark territory, whether in the offshore or deep sea.

During World War II, USS Arizona was besieged by sharks in the Pacific shark concentration area. As a result, when rescuers arrived, most of the crew on board had been buried in the fish's stomach. Oceanographers believe that sharks generally do not regard humans as prey, and it is even more rare to attack them in groups.

If the tragedy of sharks eating people really happens, in most cases, human beings should be responsible for it. It's like humans breaking into the virgin forest of India and being eaten by tigers there. Similarly, you can't blame the Indian tiger for being cruel.

Can sharks eat?

You can eat it by scalding it with boiling water, because there is sand on the shark skin, then wash it off while it is hot and fry it again.

You can also steam some water for 2-3 hours, because it is not only clean, but also tender. Put some oil in the pot, and if you like, you can put some spices such as ginger and garlic.

I think shark meat is particularly delicious, so ginger and garlic are generally not seasoned except for a little pickled pepper. Steamed shark with vinegar Ingredients: dried shark 250g Ingredients: garlic 10g Seasoning: chicken essence, salt, vinegar and peanut oil. Specific method: 1. Soak the shark in warm water for 5 minutes, then pick it up and scrape the sand off the shark skin with a knife.

2. Cut the shark into strips and put it in a plate. 3. Then, add ingredients and seasonings, and steam them in water.

Sauté ed shark with scallion Ingredients: dried shark 250g scallion 50g Ingredients: garlic 10g Seasoning: chicken essence, salt and peanut oil. Specific method: 1. Soak the shark in warm water for 5 minutes, then pick it up and scrape the sand off the shark skin with a knife. 2. Cut the shark into strips.

3. Heat the wok, add peanut oil, stir-fry the ingredients until fragrant, then add the dried shark, stir-fry until 90% ripe, add grapes and seasonings, and continue to stir-fry until cooked. Note: dried sharks can also be used to make soup and so on.

Do sharks like to eat people?

Marine biologists who study shark food in the United States believe that sharks don't like human flesh, but prefer to eat fat.

The reason may be that human flesh is too salty and not fat enough. Because of this, the great white shark will never miss every opportunity to hunt dolphins, sea lions and even whales.

Thin prey, such as seabirds or sea otters, are generally "disdainful". It is because of the habit of eating greasy food that this can explain why great white sharks bite people and then abandon them at some point.

Because of its high calories, greasy food is of great significance to great white sharks, because fat is more important than muscle in energy. In the video of sharks killing whales, it is obvious that they only eat blubber.

People also found 500 dead seals off the coast of Canada. Only the bones of the seal are left, and the layer of fat on it is gone. 1935, a great tiger shark was captured alive and exhibited by tourists in an aquarium in Australia.

Suddenly, a human arm was spit out from the tiger shark's mouth, which suddenly scared the tourists! But after forensic identification, the arm was not bitten by a shark from the human body. The police thought of a missing case that happened two weeks ago and quickly solved this strange case.

It turned out that an amateur boxer participated in a cabal, was killed by his accomplices after defeat, dismembered and thrown into the sea to disappear, and was swallowed by tiger sharks. As soon as the tiger shark swallowed the human arm, it was captured. Just because it was not interested in human flesh, it spit it out.

This incident shows that sharks really don't eat people.