Thanks to the 1975 classic “Jaws”, when people think of sharks, they immediately think of the massive Great White shark from the film. However, this famous predator only represents a tiny portion of the total global shark diversity in our world today. Sharks are the undisputed apex predators of the deep blue sea, but fearsome as they are, they now face extinction from overfishing and climate change. Keep on reading to learn about Sharks.
Fact 1: Sharks are a group of ‘elasmobranch’ fish that are characterized by a cartilaginous skeleton, and five-seven-gill slits on the sides of their head.
Fact 2: Sharks typically have tough skin that is dull grey in color, but its best not to get too close to test this fact out- we’ve all seen Jaws!
Fact 3: They have toothlike/’v’ shaped scales, known as ‘dermal denticles’, all over their bodies. These are to aid the shark as it swims through the ocean.
Fact 4: Most shark species must swim perpetually to keep themselves alive and from sinking to the bottom of the ocean. The Great White and Mako sharks are some examples of sharks who must swim all the time to ensure they keep breathing. However, some sharks have ‘spiracles’ on their bodies which help them to breathe when they are lying on the ocean floor.
Fact 5: They don’t have real bones because they’re made up largely from cartilage.
Fact 6: Their skeletons are made of cartilage, the same stuff your nose and ears are made of—it’s less dense and more flexible, so it works well for them in the water.
Fact 7: The earliest shark teeth that have been found, are said to be about 410 million years old. These teeth came from the ‘Doliodus problematicus’, which was present during the Devonian Era.
Fact 8: There are around 450 types of shark in the world. Here are some examples:
- Hammerhead shark
- Mackerel sharks
- Requiem sharks
- Ground sharks
Fact 9: Sharks come in different shapes and sizes. They range in size from the tiny dwarf Lantern shark (Etmopterus perryi), a deep-sea species that is only 20cm in length, to the mammoth Whale shark (Rhincodon typus), the largest fish in the world, which reaches approximately 12m in length.
Fact 10: Unlike humans, sharks have lots of teeth, in fact, they have about 300 teeth, which are split between multiple rows within their mouths! Their lower teeth are a more pointy shape and their upper teeth are triangular in shape.
Fact 11: The Bull shark and the River shark can live in both freshwater and seawater.
Fact 12: Sharks can be seen in all 5 of the world’s oceans: Antarctic, Atlantics, Indian, Pacific, and Southern.
Fact 13: Great White sharks are the largest known predatory fish in the sea. It’s not just the fish that have to watch out either, over the years there have been 314 unprovoked attacks on humans from the Great White shark.
Fact 14: Great White sharks can be about 15 feet in the length, which is the equivalent to an Audi A4 car.
Fact 15: Great White sharks and can weigh up to 2,268 kg.
Fact 16: Great whites can detect a single drop of blood in 100L of water, and can sense tiny amounts of blood in the water up to 5km away.
Fact 17: Millions of sharks are killed each year for their fins which are made into soup and eaten as a status symbol. The cartilage in the fins is usually shredded and used primarily to provide texture and thickening to shark fin soup. The dish is considered a luxury item.
Fact 18: The 1975 film “Jaws” is considered as the greatest shark movie ever made. “Jaws’” author had a lifelong fascination with sharks, and said that he came up with the concept for the novel after reading about a Great White shark that had been caught by fisherman Frank Mundus in 1964.
Fact 19: The smallest shark in the world is the dwarf Lantern shark which measures only 20cm long. This particular species lives in the Carribean Sea and it tends to live deep in the water, about 1000-1500 feet under the sea.
Fact 20: The largest shark is the Whale shark, which has been known to get as large as 40 feet in length, which is about the size of a bus.
Fact 21: Sharks attack approximately 100 people each year, around 10 of which result in a human fatality. However, humans kill tens of millions of sharks annually for their fins, skin and liver oil.
Fact 22: The Great White shark consumes approximately 11 tons of food in one year. In comparison, the average human eats closer to half a ton of food each year.
Fact 23: When on a hunt, sharks can generally swim to a speed of 25mph, when they need to. The average human swims at about 2mph.
Fact 24: In general, sharks “cruise” at an average speed of 5mph through the water.
Fact 25: Most sharks are “cold-blooded”. Some, like the Mako and the Great White shark, are partially warm-blooded (they are endotherms). These sharks can raise their temperature to the temperature of the water if need be.
Fact 26: Most sharks can see well in the dark, but are unable to distinguish colors, according to new research by Dr Hart from Australia, in 2011.
Fact 27: Moreover, a shark’s eye is ten times more sensitive to light than ours. Most sharks see their prey when it is about 70 to 100 feet away.
Fact 28: Sharks are known to have ‘electroreception’. This means that they can sense and receive natural electrical stimuli from the environment. To do this they have special electroreceptors known as ampullae of Lorenzini, which are jelly-filled tubes that open on the surface of sharks’ skin.
Fact 29: As sharks are some of the worlds biggest predators they have very few animal predators themselves. Some animals who hunt them are whales, orcas and other sharks.
Fact 30: Hammerhead sharks have 360-degree vision. Their panoramic view of the undersea world is inhibited by two blind spots, one in front of the snout and the other directly behind the head.
Fact 31: Sharks vomit their undigested food. Unwanted items may never get past the stomach, and instead, the shark either vomits, or turns its stomachs inside out, and ejects unwanted items from its mouth.
Fact 32: When sharks eat they tend to swallow their food whole. When the food gets to their J-shaped stomach, an acid is released that helps to breakdown all the food the shark has just eaten.
Fact 33: Sharks go into a trance when you flip them upside down. It occurs in a variety of different species, including many sharks and rays. This trance-like state can occur naturally, but it can also be induced in sharks and rays by stimulating the tiny sensory pores located on their snout.
Fact 34: Sharks are endangered as an exclusive result of human impacts and activities. According to IUCN analysts, among the approximately 470 species of sharks, 2.4% are “Critically Endangered”, 3.2 % are “Endangered”, 10.3 % are “Vulnerable”, and 14.4% are” Near Threatened”.
Fact 35: Today, the main threats to sharks include, commercial shark finning (for traditional medicine and shark fin soup), and entanglement in fishing gear.
Fact 36: Some of the earliest fossils of sharks are about 450 million years old. These fossils are of shark-like scales and are from the Late Ordovician Period.
Fact 37: Group of sharks is called a ‘gam’, but in some cases it can be ‘school,’ or ‘group’.
Fact 38: The Shortfin Mako shark, is the fastest shark, and one of the fastest fish in the ocean, it can burst up to speeds of 42mph in no time at all.
Fact 39: A baby shark is called a ‘pup’.
Fact 40: You call a female shark a ‘female shark’, and male sharks are sometimes referred to as ‘claspers’ or ‘male sharks’.
Fact 41: Gestation periods for sharks can last anywhere from 5 months to 2 years, depending on the species. The Spiny Dog Fish shark has the longest pregnancy of all sharks and vertebrates, they carry their young for 24 months.
Fact 42: Some sharks lay eggs and some actually give birth to pups. Those who lay eggs are known as ‘oviparous’ and those who give birth are known as ‘live-bearing’. Those who lay eggs can lay about 100 eggs at a time.
Fact 43: Sharks have tongues. These are known as ‘basihyal’ and serves no purpose for the majority of sharks, except the Cookiecutter shark who uses its tongue during feeding.
Fact 44: To protect their eyes if they are in a fight, for example, a shark closes its ‘nictitating membrane’ over its eyes. This is a sort of inner eyelid.
Fact 45: A Hammerheads shark has actually got a flat-shaped head and its eyes are on its ‘hammerhead’ too. Some researchers believe that the wide, flat-shaped head helps the shark to get a better sense of what’s going on around it.