13 Shark Facts You Just Won't Believe
Apr 21, 2021 | 10 minute read Comments
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Reading Time: 10 minutes

For many of us, Sharks are the ultimate terror – lifeless eyes and razor-sharp teeth lurking in the murky deep. There’s much more to this fishy family than Hollywood lets on, though. To kick off Shark Week, we’ve gathered together the most interesting and unusual Shark facts from around the world. If you think you know all about these ocean predators, think again.

1. There are over 400 Species of Shark

A chart showing the eight extant orders of Sharks with facts about how they're categorized and long they have existed
There are way too many species to fit in one picture, so here are the eight orders of Sharks.

Christmas must be a nightmare for the Shark family, judging by how big it is. There are around 450 known species of Shark, divided into eight separate orders. Each one has adapted to survive in a completely different environment: Some spend their lives thousands of feet under the sea, others have made freshwater rivers their homes. Some Sharks can even walk on land!

The most staggering thing about the family is just how much they can vary in size. The smallest species of Shark is the Dwarf Lanternshark. It grows just 6 inches long, and weighs half an ounce. Compare that to a Whale Shark, which can reach 40+ feet and over 20 tons!

Out of all these fish, how many do you think attack humans? Half, one quarter? Try 3%. Only 33 species have ever been known to harm people. Take out the one-off, freak encounters, and that number drops to 15 “dangerous” Shark species. In fact, the vast majority of attacks were from just three Sharks: Bulls, Tigers, and Great Whites

2. They’re Older Than the Dinosaurs

A fossil of an ancient Shark

Sharks have been around for a really, really long time. For reference, the very first dinosaurs evolved 240 million years ago, and T-Rex didn’t show up until 70 million years ago. Sharks make these ancient fossils look like the new kids on the block. The earliest examples people have found are over 450 million years old!

That’s not even the crazy part. While the rest of life on earth evolved and adapted into something completely new, many Sharks stayed more or less the same. Some species, like the Goblin Shark, have been around for over 100 million years without changing at all.

It’s a classic case of “if it ain’t broke, don’t fix it.” Sharks have always been the perfect predators. They found their place at the top of the food chain a long time ago, and never saw much reason to change.

3. They Can Live for Hundreds of Years

A large Greenland Shark, one of the longest-living animals on earth

Continuing with the “they’re really old” theme of Shark facts, Greenland Sharks are some of the longest-living animals on earth. Scientists estimate that they live for up to 500 years. They don’t even reach adulthood until they turn 150.

How does an animal live that long? By adapting to a life in the slow lane. Greenland Sharks are the slowest-moving fish in the sea. Their maximum speed is around 1.6 mph, and they usually plod along at half that. They cruise the depths of the Arctic Ocean, thriving in waters barely above freezing. 

Despite all that, they’re huge. Fully-grown Greenland Sharks can top 20 feet and weigh over half a ton. They’re a real poster child for the old saying, “Slow and steady wins the race.”

4. You Can Count Their Rings, Just Like Trees

The rings of an old tree

You may be wondering, “How can we know how old a Shark is if it lives longer than us?” It’s not like several generations can keep a family Shark – it’s not a tortoise. A lot of what we know about the age of Sharks is guesswork and math based on how big they get and how quickly they grow. However, there’s a much more interesting way to find out their age.

Shark skeletons are made of cartilage, not bone. Because of this, their backbones grow in layers as they get older. Scientists can scan and count these layers, just like you’d count the rings on a tree. Once they work out how long a layer takes to grow, they can calculate exactly how old the shark is.

5. They Never Need to Go to the Dentist

A close-up of a Tiger Shark's mouth underwater, with other fish swimming around in the background

Sharks spend a lot of their time biting things – at least, that’s what they always make the headlines for. With such a busy schedule of chomping and chewing, you’d think that they’d need a serious dental plan to keep those pearly whites in order. Underwater dentists are in short supply, though, so they’ve had to adapt instead.

To begin with, Sharks come with a built-in supply of toothpaste. Researchers in Germany found that the teeth of several Shark species contain fluorinated calcium phosphate. That means nothing to us, either, but we’ve been reliably informed that it’s a main ingredient in toothpaste.

Even if Sharks do lose a tooth, it’s no big deal – they can just grow another one. Unlike humans, Sharks aren’t limited to a puny two sets of teeth. They’re constantly replacing them, and some species get through an incredible 30,000 teeth over their lifetime!

6. Their Skin is Covered in Teeth!

A microscopic image of the small denticles or teeth that make up Shark skin
Source: Pascal Deynat/Odontobase, Wikimedia, CC BY-SA 3.0

Not satisfied with a never-ending supply of teeth in their mouths, Sharks have also grown them all over their skin. Shark skin is made up of tiny scales called “denticles.” They look like endless rows of teeth, and that’s pretty much what they are. They’re made of the same enamel as human teeth, only they’re not designed for biting things.

When a shark moves, each individual denticle creates a vortex, a pocket of low pressure. This lets them swim more silently and efficiently than other fish. They can also flex and bend their scales to turn more quickly. In fact, they’re so aerodynamic that engineers have been looking into using the design on airplanes.

Shark skin is good for more than just speed, though. It also acts as a secondary skeleton. Sharks don’t have proper bones, so their muscles attach to the inside of a “corset” of scales, instead. Sharks are covered in an exoskeleton of razor-sharp teeth. Talk about overkill!

7. Sharks Will Eat Almost Anything

A sign warning about Sharks in the water which has a bite taken out of it

If there’s one place where the silver screen meets real-life Shark facts, it’s that they’ll eat anything. Sharks are inquisitive by nature, especially the large predators like Great Whites and Makos. Combine this with the confidence that comes from sitting at the top of the food chain, and you get some weird things turning up in their stomachs.

Greenland Sharks grow fat and happy on a diet ranging from fish and seals, to moose and even polar bears. Great Whites are famous for taking bites out of boats, but did you know they’ve also been found with an entire suit of armor in their stomach? Seriously, there’s no end to what they’ll try a nibble of.

Sadly, these wacky snacks don’t do Sharks any favors. The thing that most commonly turns up in their stomachs is plastic. Sharks regularly wash up with a stomach so full of plastic that they couldn’t eat anything else (warning, it’s not a pretty sight). They’re either taking the term “junk food” way too literally or, more likely, mistaking it for prey like jellyfish and squid.

8. You Can Put a Shark Into a Trance by Petting It

A scuba diver putting a Shark into a trance by turning it upside down and petting its belly

Sharks have a reputation as fast and furious hunters. They tear through the ocean, gobbling up whatever comes their way. That’s certainly true for the most part, but these apex predators also have a more relaxed, zen side that gets triggered when you rub them on the nose.

How does this work? Tonic immobility, or as beastmasters call it, animal hypnosis. Some animals go into a paralyzed “trance” in response to specific stimuli. For Sharks, that includes having their noses fondled. You can also knock them out by flipping them upside down.

Nobody knows exactly why this happens. To be honest, the more important question should be, “Who discovered this in the first place, and why?” Were divers just flipping fish onto their backs for fun? Was it a heat-of-the-moment response to a Shark attack? We could ask the Sharks, but they’re probably still too out of it to make much sense.

9. Female Sharks Can Get Pregnant All On Their Own

A Zebra Shark swimming around a reef, with smaller fish in the background

The more Shark facts we learn, the more we realize that they should probably have taken over the planet by now. A prime example of this is Leonie, a female Zebra Shark kept in captivity in Queensland, Australia.

Leonie used to be in a stable relationship with male Zebra Shark Leo. One day, she was moved to a new tank away from Leo and all other male Sharks. She spent three years without a mate before she decided enough was enough and just straight up made herself pregnant.

Among scientists, this is called “asexual reproduction.” Leonie wasn’t the first one to do it – lizards, snakes, and even other Sharks have managed it in the past. The difference is that Leonie had already had babies the old fashioned way before. This was the first case of animals switching to asexual reproduction, and proof that Sharks will adapt and thrive in any situation.

10. Sharks Solve Crimes

A Shark superimposed on a police lineup board
I’m innocent!

So we know that Sharks are intelligent. We know they’re cunning. But did you know that they sometimes moonlight as detectives? At least, that’s what happened in 1935 in Sydney, Australia. In what must be the most bizarre legal case of all time, a 14′ Tiger Shark helped solve a murder.

The Shark was caught in the waters off Sydney and transferred to the local aquarium. After a couple of days, it fell ill and started to vomit. Among its recent meals, aquarium workers found a human forearm floating in its tank. Pretty crazy, right? But here’s where things get really interesting.

The Tiger Shark wasn’t the killer at all – it had eaten another, smaller Shark. So the smaller Shark did it? Not so fast. When investigators studied the arm, they soon found that it had been severed with a knife. They took fingerprints and cross-referenced them with a distinctive tattoo of a badly-drawn boxer decorating the mysterious limb. 

The police identified the victim as a former boxer and petty criminal, James Smith. They tracked down his movements and arrested the person responsible. The Shark went on to open a P.I. firm, eventually taking down several notorious Aussie gangsters. Okay, maybe not, but the way this story turned out, we wouldn’t be surprised.

11. They’re Avid Metalheads

An illustration of a Shark wearing sunglasses and listening to loud music on headphones, with text above reading "Let's rock!"

Along with wolves and snakes, Sharks are probably the most “metal” animals out there. There’s a hefty list of bands with Sharks on their album covers, after all. What most of them probably don’t realize is that these ocean terrors are some of their biggest fans.

As with many of the most bizarre Shark facts, this one comes out of Australia. A cage diving tour operator named Matt Waller had a habit of pumping out his favorite tunes during his tours. He soon learned that the fish became more inquisitive and a lot less aggressive when listening to music. Specifically, the greatest hits of AC/DC.

Waller believes it has something to do with the specific frequency of the music, or the vibrations it causes in the water. We’re siding with the “Sharks are just badasses” argument, although this has yet to gain traction within the mainstream scientific community.

12. Sharks Kill Fewer People Than Coconuts.

Two halves of a coconut on a white background

If there’s one thing we know about Sharks, it’s that they’re basically underwater killing machines, right? Jaws. Deep Blue Sea. Sharknado. We’ve all seen the movies and there’s one thing they all agree on: Sharks are deadly. Or are they?

Now don’t get us wrong, there’s definitely some truth to the idea of Sharks being dangerous. They’re responsible for unprovoked attacks on swimmers and beach-goers all around the world, and every year, people lose their lives in Shark attacks. How many exactly? About five. Worldwide.

Yes, shockingly enough, it seems that Hollywood has been over-hyping certain threats while they play down the real dangers in life. Want to know what you should be scared of? Coconuts. Coconuts kill about 150 people each year, a number that all of the world’s Sharks would need 30 years to catch up with. And that’s just the start of a long list of things more likely to kill you than Sharks.

13. Sharks’ Greatest Predator? Us

A hand holding a severed shark fin over water

So, Sharks aren’t nearly as dangerous as people make out. It’s almost as if they’re being framed. Wait a minute, what if we’re the bad guys? Tragically, we kind of are. People kill around 100 million Sharks each year. That’s three Sharks every second of every day, all year long.

According to the International Union for Conservation of Nature, around a quarter of the world’s Sharks and Rays are at risk of extinction. A lot of them are caught by accident on longlines or in trawler nets. They also end up in traditional “medicine” sold as anything from cancer cures to aphrodisiacs.

However, the reason most Sharks are killed is to make soup. People catch them, cut off their fins, and throw them back – often while they’re still alive. The fins are then used to make shark fin soup, a traditional feasting dish and delicacy in China and Vietnam. This is despite the fact that the fins add no flavor or nutrition to the meal.

Sharks Are Amazing

A large Whale Shark swimming underwater near the surface

These are some of our top facts about Sharks, but there are way more out there. Sharks are incredible creatures, and a vital part of our oceans’ ecosystems. The one fact we can’t ignore is that we need to do more to protect them, before it’s too late.

Can’t get enough of interesting Shark facts? You’re in luck! This is just part one of our Shark Week Specials. Come back all week for more Shark-themed fun!

Comments (12)
  • michael

    May 26, 2021

    sharks can grow up to 20 feet long

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      Andriana

      May 27, 2021

      Hello Michael,

      You’re right, a lot of Shark species stay in the 20′ ballpark, but Whale Sharks, for example, can grow to be a whopping 40′ long. Talk about true giants of the sea!

      All the best, Michael!

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  • Robert smith

    Jun 23, 2020

    Sharks greatest predator is not humans but KILLER WHALES.

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      Albert

      Jun 23, 2020

      Hi Robert,

      Will have to disagree with you on that one sadly. Studies have shown that people kill over 11,000 Shark per hour, every hour.

      Killer whales are definitely the better predator, though.

      All the best!

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      Ami Jo

      Jul 2, 2020

      100 million sharks are killed a year

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      Albert

      Jul 2, 2020

      Hi Ami,

      Yup, tragic but correct.

      Hopefully, governments around the world start to make more of a commitment to protecting these incredible creatures.

      All the best!

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      Tanya R McLaughlin

      May 9, 2021

      Sorry,but I do not believe this is correct. From info Ive read,3sharks per second,every second, all day,everyday,365 days a year,So 100 million Sharks are taken out. Somes accidental,but most are killed for human consumption. I do believe while Killer Whales are beautiful creatures in appearance.

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  • Trevor

    Feb 25, 2019

    Well, I think mosquitoes are annoying fishermen more than sharks do. I have never been bitten by a shark but every time I go fishing (except of winter time) those bloodsuckers are driving me crazy…

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      Tanya R McLaughlin

      May 9, 2021

      Lol,sadly mosquitoes are responsible for 100k people per year. Sharks didnt even make the list!

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  • dtfranks

    Jul 12, 2016

    “These fish have headlined as many horror classics as National Geographic specials, yet despite our incurable obsession with the deepwater predator, our knowledge of them is often superficial, misguided, or just plain wrong”
    I disagree. Read this.
    David

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  • Fernando

    Aug 13, 2014

    I had a lot of fun reading this article :))

    I blame Spielbergs’ Jaws for this shark fear!

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      jesse

      Oct 31, 2019

      why do you blame spielberg

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