Fact and fiction about sharks

Humans are hypnotized by sharks by information that mixes truth and superstition, between legend and reality, and by concerns about the unknown. A bit of knowledge about them will make the sea trips become great experiences.

Here are 20 facts about sharks:

1. White sharks can grow about 24.5 cm per year. When mature, they can be from 3.6 to 4.2 meters long.

2. New teeth are constantly formed in shark teeth. They are usually renewed every 8 days.

3. Some sharks can grow up to 30,000 teeth in life.

4. Whale sharks have about 300 teeth, each with hundreds of tiny ones.

5. Dry shark skin (shagreen) has been used as sandpaper. In Germany and Japan, shark skin is wrapped in a grip to prevent slippery.

6. In 1937, shark liver oil was discovered to be rich in vitamin A. So from then until 1950, they were hunted to exploit this vitamin, until a new method of synthesizing vitamin A was born. .

7. The average life span of sharks is 25 years, but some species can last up to a century.

8. Dogfish sharks are named because of their predisposition to hunting like the wild dogs do.

9. White sharks can survive up to 3 months without eating anything.

10. Not all sharks must breathe continuously.

11. Cow sharks can withstand salinity changes and often live in freshwater rivers and lakes in Africa and South America.

12. More people die each year because dogs, pigs and deer are more likely because sharks.

13. Pygmy shark (dwarf shark) has a maximum length of 28 cm.

14. Sharks have no bones. Its frame is made of cartilage.

15. Science has known over 340 shark species.

16. Sharks first appeared in fossil specimens more than 400 million years ago.

17. A very significant physical trait that distinguishes modern and ancient sharks is the protruding jaw, which gives the modern shark more powerful bite.

18. Sharks can produce bite forces of about 6.5 tons per square inch (1 inch = 2.54 cm).

19. Shark skin is cushioned with small protrusions, similar to teeth.

20. The Mako short fin shark may be the fastest fish in the sea, at a rate of about 96 km / hour.

How sharks attack:

There are 3 basic types of situations where innocent sharks attack:

1. "Crash and run" is the most common attack. They often occur in waves of waves. Victims rarely see sharks and it does not return after leaving a bite or tear wound. Most of these attacks are the result of confusion, which occurs when turbid water and harsh environmental conditions like waves and strong currents. The victim's wounds are usually torn legs below the knee and rarely life-threatening.

2. "Crashes and bites" often cause more serious and easier wounds. These attacks often involve divers or swimmers in deep water. The initial shark will hover around and often crash into the victim before the real attack begins.

3. "Stealth attack" happens without warning. The shark will repeat bites or clamp the person in the mouth. Wounds are often very severe, and easily fatal. It is believed that this type of attack is the result of feeding behavior and not confusion.

How to avoid being attacked by sharks:

1. Swim in groups. Sharks often attack individual riders. Avoid getting into the water at night, dawn or dark.

2. Do not enter the water if you are bleeding. Sharks can smell and recognize the smell of blood and its source. Do not wear sparkling jewelry. Sharks will see it as sparkling fish scales.

3. Not much water. That will attract them. If you see a shark in the water, don't approach it and don't try to touch it.

T. An