Facts About Sharks – The shark is a cartilage fish and its scientific name is “Selachimorpha” or also “Euselachii”. They are related to the stingray. Fossils have been found showing that the very first specimens date back to 425 to 455 million years ago. In comparison, the dinosaurs didn’t come into existence until 200 million years later. There are about 400 species of sharks and together with the rays, stingrays (600), and the little-known dragon fish or Holocephali (30) they form the family of the cartilaginous fish.
A shark can be described as a torpedo-shaped fish with a large triangular dorsal fin and a sickle-shaped tail. But besides this typical image, many others have the looks of a whale or the so-called reef sharks that have a wedge-shaped head to stick into the reefs. Then you have the eel-shaped shark (Frilled Shark) and the wobbegong, a shark that camouflages itself between coral or seaweed. Another special species is the epaulet shark that can walk on its fins.
The smallest shark species is Etmopterus Perryi (dwarf lanternshark) and grows to only 17cm. The largest species, the whale shark can grow up to 12m in length. Most sharks fluctuate between 1 to 2 meters. The shark’s food consists of fish, marine mammals, birds, mollusks, and crustaceans.
Most sharks live 20 to 30 years except for the whale shark which can live up to 100 years old. Most sharks reproduce by laying eggs, but some species give birth to live young.
What is also special with sharks is that they never become toothless. If they lose a tooth, it is immediately taken by another tooth from the next row. Usually, they only lose 1 or 2 teeth at a time, but the dogfish swap an entire row of teeth at the same time. The longer the shark lives, the larger its successive teeth become. In its entire life, a shark wears out more than a thousand teeth.
Facts About Sharks: Some Species
Facts About Sharks: Sharks and humans
Humans are still fascinated by the shark. Especially the dangerous species appeal to the imagination. Now it must be said that there are about 400 species of which only 4 or 5 species are dangerous. But most people think mainly of a “Jaws” type who performed in the movie of the same name. The vast majority of sharks are located two thousand meters below the surface of the water.
The very first sharks (megalodon) are said to have been gigantic and had teeth measuring 6 inches long. They were also called the big tooth sharks. Now, these sharks have long since become extinct. They are said to have lived about 23 to 3.6 million years ago.
Some wonder why these sharks became extinct. A study found that this was due to a tsunami of cosmic energy from a supernova. This is said to have happened about 2.6 million years ago. To claim that the melagodon would still exist is purely a myth because in our contemporary world we would have known that for a long time.
Many people think that a shark will always attack and are therefore very afraid of these types of animals. But nothing is less true. If you let the shark stay in its territory then there is nothing to fear. On the other hand, if you are someone with bad intentions and you want to penetrate its environment, the shark can attack effectively. But they are not going to kill humans for that. As I said, only 4 or 5 species (out of 400) are dangerous to humans.
There is much more chance that humans are attacked by other sea creatures such as a sea crocodile, an octopus, box jellyfish, or stonefish. The well-known types of sharks that are dangerous to humans are the white shark, the sand tiger shark, the tiger shark, and the bull shark.
A further study has also indicated that most shark attacks are based on a shark’s mistake in which the animal thought the human is a seal. A tip: avoid swimming around sharks at dusk because then the animal will look for food and a mistake will happen sooner.
If a shark smells blood, it can become dangerous and there have been many accidents with recreational divers who go fishing with harpoons. In the end, they did look for it themselves a bit. People’s concern was also sparked by the movie world featuring the 2 most famous movies “Jaws” and “Deep Blue Sea”. What is striking is that the largest sharks are the least dangerous. So you have the whale shark, the giant beak shark, and the basking shark. These animals mainly feed on small animals, the so-called plankton.
Be wary of:
Maybe hard to believe, but the shark has also influenced swimming. Since this animal has no scales like the bony fish, but its skin is covered with very small teeth. This makes his skin look very smooth. These teeth consist of the same material as those in the mouth. The profile of those skin teeth ensures that the predator is very fast because there is no turbulence.
That is why the same technique was used in swimming. The swimwear became, as it were, a kind of synthetic shark skin. In sports, they are called “fastskins”. As a result, the swimmer also got less flow resistance and could therefore swim faster. In 2000 these swimsuits first appeared at the Summer Olympics in Sydney. They were worn by various famous swimmers. In 2010, however, the use of these types of fastskins was banned by the International Swimming Federation.
Facts About Sharks – Senses of the shark
Sharks have very fantastic senses. These are of course very useful when the animal is going to hunt.
Many people think that sharks cannot see well, but the opposite is true. Their eyesight is perfectly developed and, like the vertebrates, they also have a retina, a cornea, and an eye lens. What makes the eyes special is that they are adapted for marine life. This is done by a type of tissue located behind the retina. The scientific name for this is “tapetum lucidum”. A similar tissue is found in the eyes of cats and dogs. But here the fabric has a different function, namely to be able to see better in the dark. In contrast, in shark eyes, the tissue serves to keep the eyes wet so that the shark never has to blink. What is also special is that the shark has an extra thick eye membrane that protects the eye when attacking prey. The great white shark is an exception. This animal rolls its eyes back into the eye sockets when it attacks prey.
A shark’s sense of smell is unimaginable! For example, certain species can detect a millionth of the blood dissolved in seawater. They have an automatic reflex that they look in the direction of the nostril in which the scent could first be smelled. Of course, with their fantastically developed sense of smell, they can detect possible prey from a very great distance.
The shark mainly uses its sense of smell to locate prey at a far distance. On the other hand, they use the “electrical sense” for any nearby victims. The animal has small sense pores in its head that allow it to detect objects in its immediate vicinity. The scientific term for these sense pores is “Lorenzini’s Ampoules”. Hundreds or even thousands of these are present in the shark head. Also, changes in the magnetic field are perfectly perceived. Even prey that has hidden under the sand can also be found by the sharks.
Unlike the shark’s size, the ears are very simple little openings on either side of the head. The ear does not have an eardrum, but this is compensated by the surrounding water, which is a very good conductor for the sound. Most vibrations are observed in the surrounding area between 25-50 Hz. The ears can also be seen as a kind of barometer because a shark quickly becomes aware if, for example, a natural disaster is imminent. This way they know when a thunderstorm or a hurricane is approaching and then they flee to greater depths. They do this by observing changes in water pressure. In this way, they want to avoid any physical damage.
Facts About Sharks – The living environment of the shark
Normally the shark is an ocean inhabitant, but one can also be found in the seas. They reside in clear and dark water, in the tropics, or the icy polar regions. Some seek out river estuaries or settle in the vicinity of mangroves, rocky coasts, or coral reefs. There is even one specimen that dares to venture into freshwater, the bull shark. The Greenland shark hides under the polar ice.
Certain species only occur in a specific area such as along the eastern coast of Australia (long-nosed swallow shark) or the whitefin dogfish that only resides around Japan. But most of them are worldwide distributed and occur in the Atlantic, Pacific, and Indian Oceans. And also in the Mediterranean. An example of this is the thresher shark.