Sharks are the apex predators of the oceans, but they’re more than movie monsters and beach horror stories. There’s a lot that most people don’t know about sharks and plenty more that scientists are still learning about them. More than 500 species of sharks swim the ocean depths, making up a diverse and endlessly fascinating group of animals who have been hunting the waters for millions of years longer than humans have been walking around on Earth.

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We’re still learning

Sharks are ancient creatures who inhabited the Earth at the same time as the dinosaurs. But that doesn’t mean we know everything there is to know about them. In fact, we’re still making discoveries. The megamouth shark was only discovered in 1976, and fewer than 100 of these rare sharks have ever been seen. It grows to an average of 16 feet, we think, and siphons plankton out of the water to feed. Even more recently was the discovery of the pocket shark, a 5-inch shark found in the Gulf of Mexico. It glows under the water to attract prey.

Related: How your beauty routine might be killing sharks

close-up of Smalltooth Sand Tiger Shark

Their teeth are healthier than yours

Shark teeth are totally resistant to cavities. The teeth of sharks are covered in fluoride, an enamel known as fluorapatite. This material is resistant to acid created by bacteria. Sharks also go through several sets of teeth in their lifetimes, shedding and growing new teeth periodically. An average shark mouth will see about 30,000 teeth in one lifetime. Shark teeth are much healthier than human teeth, which need constant care and maintenance.

They can clone themselves

Through a process that has been observed in many animals, sharks can clone themselves through parthenogenesis, a type of external fertilization. This has been seen in female sharks being kept in captivity.

Sharks aren’t that dangerous

Humans are a far greater danger to sharks than they are to us. Though it makes for a pretty good movie, there are fewer than 200 shark-human interactions globally every single year. Meanwhile, humans kill about 100 million sharks annually, mostly through hunting. Sharks have a variety of feeding habits. Many species of sharks are filter feeders that eat small marine life, such as clams, and many are bottom feeders who use suction to gather food. Only some species of sharks are hunters that attack seals, dolphins and other large sea creatures.

They’re resilient

Not only did sharks survive the extinction event that brought an end to the dinosaurs, but they’ve also survived five total mass extinction events on planet Earth. Sharks first appeared in the planet’s oceans over 400 million years ago. That makes them even older than trees. Sharks were swimming in the oceans before dinosaurs roamed the planet. They survived a mass extinction event that killed 75% of all living species on Earth, including many ocean-dwelling species. Then, they survived an event that killed 96% of all marine life on the planet. This is why sharks are often referred to as “living fossils.”

spotted whale shark in the ocean

The great white isn’t the biggest shark

Movies have made the great white shark famous as a predator, but it’s not the biggest shark in the ocean. That honor goes to the whale shark, which grows up to 60 feet in length. Though it has the size, the whale shark doesn’t have the terrifying look that makes the great white shark so distinct. This giant of the water feeds on small fish, plankton and invertebrates. That means whale sharks don’t have those razor-sharp teeth and huge jaws that make the great white shark such a perfectly terrifying villain. By comparison, the great white shark grows up to 20 feet at most.

They have a sixth sense

Sharks have the same five senses as human beings — plus one more. Sharks have an organ in their snouts, ampullae of Lorenzini, that allows them to sense electrical fields in the water emitted by other fish and marine life.

Lion vs. shark?

In the battle of lion against shark, if such a battle was possible, sharks would win pretty easily. A lion bite is weaker than you might imagine, about 650 PSI (pound-force per square inch). A shark bite is much more powerful. In a single snap, a great white shark can produce up to 4,000 PSI.

Grey reef shark swimming in ocean

They don’t vocalize

Despite what you may have seen in “Finding Nemo,” sharks definitely can’t talk, even to other fish. Sharks have no vocal cords; therefore, they make no vocal sounds whatsoever. Instead, they communicate through body language.

A mega shark was once real

“Jaws” isn’t just a movie, it’s reality. Well, kind of. There once was an enormous shark that swam the ocean depths. The megalodon inhabited the Earth’s oceans 20 million years ago, becoming extinct about 3.6 million years ago. This monster was the largest shark to ever swim the oceans and the largest fish the planet has ever known, up to three times the size of the longest great white shark.

Sharks are truly fascinating creatures, and they have much more to fear from us than we do of them. They’ve managed to survive on a planet that’s known for being rocked by massive extinction events, living long enough to see the rise and the fall of the dinosaurs and the evolution of plant life on the planet. Now, they swim the same waters as human beings. The more you research about these hunters of the deep, the more you’ll find that learning about sharks is pretty fun.

Via NOAA and WWF

Images via NOAA (1, 2, 3, 4)