Shark is an apex predator that roams the oceans across the world. Unlike other fish their looks, size and behavior give them a majestic presence. They are living on Earth before the dinosaurs did and spread their numbers almost the entire planet. They are very efficient killing machines that can be found in salt or fresh waters. So whenever you head up for the beach you might encounter any of them, and they are strong. So, it’s better to understand these magnificent creatures, which could help you to avoid or to escape from them.
1. Shark is an Chordate species from Chondrichthyes class. They have cartilaginous skeleton, 5 or 7 sets of gills and a Pectoral fin. They are the closest relatives of Stingrays.
2. They are older than dinosaurs. Fossils found ageing more than 455 million years suggest they are from Silurian period, when coral reefs started forming.
3. There are about 500 species of sharks including some lesser known Bullhead shark, Carpet shark and Dogfish shark. They range from Dwarf lantern Shark, which grows up-to 6 inches to gigantic whale shark, which stretches up-to 40 feet and weighs about 20 tonnes.
4. They don’t have bones in their body. Instead, they are Elasmobranch, meaning their skeleton is made of cartilaginous tissues. These are lighter than bones giving better buoyancy. But, as they age, calcium salts get deposited on their skeleton giving strength. Hence, they got fossilized even without having real bones.
5. Sharks have Tapetum behind their eye balls. Which make them excellent in identifying colors with good night vision. Even they can warm up their eyes for better visibility in cold waters. Hammer Head sharks have 360 degree view with binocular vision due to their peculiar head. Their eyes are placed at the end of their head extensions.
6. Some of the Shark species have very acute sense of smells. Like the Great White shark has an organ known as the Olfactory Bulb connected to their nostrils, which allow them to smell one drop of blood in a water filled Olympic size swimming pool.
7. Rather than vision and smell they do have an extra sixth sense. They have numerous black spots near eyes, nose and mouth area. These are eletroreceptors known as Ampullae of Lorenzini. They do sense the elector-magnetic field and ocean temperature changes by these organ. The Hammer Head shark has the most density about 3000 spots present on their head.
8. Their skin is like sand paper, because they have tiny teeth called Placoid scales on the skin pointed towards the tail. These make a water layer just above their skin, which reduce the water drag and give high speed while swimming.
9. All sharks have different types of teeth and bite marks. Like, the Mako shark has pointed teeth whereas the Great White shark has triangular, serrated teeth. Some have unique tell-tale mark like the Cookie Cutter shark has a full circle bite mark. Sharks do have many teeth in their life time, like 35,000-50,000 teeth. They have almost 15 rows of teeth in each jaw which get replaced very often.
10. They do swim their entire life and couldn’t stop due to their respiratory system. They can take water in only by swimming forward and release through their gills. Although, some bottom dwelling sharks like Angel Sharks and Nurse sharks do have spiracles behind their eyes which helps them to take water in and extract oxygen while resting on sea floor or even eating.
11. Great White Shark has almost 4 times stronger bite force than any lion or Tiger. A 20 feet long Great White can bite with a force of 4000 psi (pound per square inch), whereas a lion has 1200 psi. Although, as per size comparison the Bull shark can bite harder. It has been observed that a 8 feet Great White shark can bite with 360psi of force but, a 9 feet Bull shark did score 478 psi due to their vice like Jaws.
12. Not all sharks do live in oceans, some are well adapted to live in fresh water also. The Bull shark can live in both fresh water like lakes and salt waters whereas, the River sharks can be found in rivers or waterways in South Asia, New Guinea and Australia.
13. Great White sharks don’t kill its prey by struggle, instead they do it in style. To hunt an elephant seal, it just waits below the seal’s swimming depth and suddenly strikes from underneath by ramming. Then it bites the seal’s hindquarter and left to bleed. After the prey dies, the shark returns to have its meal without any struggle.
14. Tiger sharks are called trash cans of the ocean. They just eat whatever fits in their mouth. In research, objects like car licenses plate, money purse, poly bags, camera, nail polish and many other had been found in their stomach.
15. The Goblin shark can grow up-to 10-13 feet, has a pink skin and a crazy looking elongated snout. It definitely looks creepy but, interestingly these species is living for 120 million years on Earth and known as the “Living fossil“.
16. Whale shark skin is 6 inches thick, making it like a bullet proof vest. So thick for researchers to pierce and get blood samples even very difficult to place tracking device under their skin.