These 470 shark species, classified in 8 orders and 37 families. Sometimes they rest on the bottom of the ocean. Therefore many sharks have to swim constantly to avoid sinking. This organ is the one that regulates buoyancy in many marine animals. Instead, they have skeletons made of cartilage, a flexible and lighter tissue which is also considered bone but gives sharks the speed underwater and the flexibility they need to be the dominant predators they are. Shark skeleton material is not strong, dense bones like terrestrial vertebrates. Instead of bones, the skeleton of sharks is composed of cartilage, a flexible, robust and less dense substance. Sharks inhabit all the waters of the worldīelieve it or not, sharks can live in all oceans and often prefer the areas near the coast. There is evidence that sharks have been on Earth for more than 420 million years this means that they were dwelling the oceans when dinosaurs ruled on land. Instead of surfacing to breathe, they use their gills to get oxygen from the water. Like any other fish, they rely upon their gills to allow them to breathe while underwater. Sharks don’t need to reach the surface to breathe like some marine mammals. Anyone who wants to discover more than “the shark is a ferocious marine animal,” must know these ten quick facts: 1. There is a lot of information, curiosities, and relevant data about sharks available that worth knowing. ![]() Sharks spend their entire lives in the ocean doing all they can to survive, and they have performed this task quite well. However, as you learn their main facts, you will appreciate them for what they are. With an average lifespan of 20 to 30 years, a shark can use thousands of teeth over its lifetime.Due to wrong publicity, sharks have a bad reputation. Some sharks can produce up to eight rows of teeth at once, and it takes a shark as little as 24 hours to produce a replacement tooth. The teeth in a shark’s mouth are arranged in progressive rows, and should a tooth fall out, the next one behind it moves up to take its spot, like a rotating dental Rolodex. But a shark’s teeth are attached by soft tissue to the skin covering the jaw, and easily fall out if they wear out or break. ![]() A human tooth rests in a socket and falls out once during adolescence. Technically, the serrated and pointy pearly whites just regenerate as needed. Sharks don’t come out of the womb outfitted with endless rows of teeth. Great Whites and the Whale shark do need to keep moving to breathe.Ĥ. Most sharks do not need to constantly swim to breathe or stay alive – but there are some exceptions. On the opposite end of the spectrum, the whale shark (above)-the largest fish and shark of them all-reaches lengths up to 40 feet or more, and is a migratory filter feeder whose diet consists of mostly planktonģ. ![]() It’s so little of a threat, in fact, that even fishermen discard them if caught because they’re too small. This little guy, found off the coast of Venezuela and Columbia, is possibly the smallest shark in the world and can fit in the palm of your hand, reaching a maximum length of 21 centimeters. Take the dwarf lantern shark, for instance. ![]() While those species-and others such as the blue shark or the mako shark-are apex predators that reside on the top of the food chain, there are plenty of other species of sharks that go against the misconception that all sharks are predatory. Yet popular opinion tends to veer towards the great white or the hammerhead out of sheer fascination and fear, thus propagating the myth that all sharks are dangerous and bloodthirsty hunters. There are over 400 different species, so there’s no such thing as a typical shark. Sharks may not hunt and eat humans, but they’re all vicious predators. In fact, most of the time, shark bites are actually “ exploratory bites” in which a curious shark tries to determine if what it’s biting is food.Ģ. When an attack does occur, it’s most likely that the territorially-minded shark has mistaken the human for its actual prey (a seal, for example). While sharks may sometimes attack humans, sharks don’t seek out humans for food.
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