Sharks have long been portrayed as predators who are only after human blood. But that's not the case at all. In an effort to set the record straight on what sharks are really like, we thought we'd do a little digging to discover some of the most interesting shark facts.
It's Shark Week, after all, so celebrate with us and tell us how many of these cool facts you already knew!
1. Sharks have survived five mass extinctions.
The last one, which dates back to 65 million years ago, killed off the dinosaurs, but the sharks just kept swimming.
2. Unborn sand tiger sharks are cannibals.
It’s true. While in the womb, the largest sand tiger shark eats all but one of its unborn siblings. It’s all part of a twisted paternity struggle in which cannibalization allows only one father’s offspring survive.
3. Sharks love AC/DC.
Two researchers recently tested the effects of different types of music on shark behavior. AC/DC — specifically the songs “You Shook Me All Night Long” and “If You Want Blood (You Got It)” — resonated with them. They became more investigative and inquisitive, and less aggressive. Rock on.
4. Greenland sharks could live to be over 500 years old.
Photo Credit: Julius Nielsen/Science
A study published in the journal Science last year found “with 95 percent certainty” that one Greenland shark was between 272 and 512 years old, making Greenland sharks the new record holder for longest-living species of known vertebrates.
5. Sharks have two penises.
Well, not exactly. The two appendages are actually called claspers, but they fulfill the same purpose as penises would — delivering sperm into a female shark. And, in case you’re wondering, they only use one clasper at a time.
6. They don't all look like great whites and sand tigers.
A wobbegong, a type of carpet shark found in the Indo-Pacific.
Your first thought when sharks are mentioned might be a great white or a hammerhead, but there are more than 400 species. From small and harmless to large and fearsome.
7. Their livers are what keep them afloat.
Sharks are good swimmers, but they have their livers to thank for much of their buoyancy — they're very oily, which helps them keep their balance.
8. Thresher sharks hunt like scorpions.
9. Hammerheads sometimes live inside volcanoes.
Back in 2015, scientists discovered hammerhead sharks casually swimming around in an active underwater volcano like it was NBD. The Kavachi volcano, located just south of the Solomon Islands, is often spewing lava and ash, so we’re talking about some fearless, badass shark inhabitants here.
10. One-quarter of sharks and their relatives are threatened with extinction.
Thanks to overfishing and illegal fishing operations, sharks are at risk. This could have major impacts worldwide since sharks are generally at the top of the food chain, regulating the populations of fish species below them.
11. Sharks sometimes vomit out their entire stomach.
And it looks just as gross as it sounds. It’s called gastric eversion, and it literally means to turn your organs inside out. It’s a defense mechanism that’s been observed in lemon sharks, shorten mako sharks, tiger sharks and Caribbean sharks, who do it after accidentally eating something toxic, or as a reaction to extreme stress. Who’s hungry?
12. The shortfin mako shark can travel up to 60 miles per hour.
Typically, the maximum speed of an average shark in short bursts is about 30 miles per hour. However, the shortfin mako is not your average swimmer and comes close to matching the cheetah when it comes to speed. Basically, you don't want to get caught trying to take this guy's tuna dinner. You'll lose.
13. Some sharks glow disco colors the deeper they swim.
Photo Credit: © J. Sparks, D. Gruber, and V. Pieribone
Chain catsharks have molecules in their skin that absorb light and re-emit it as another color, aka biofluorescence. This particular species absorbs blue light and re-emits it as bright green — and just last year, scientists figured out why.
Their disco patterns differed by species and sex, leading researchers to believe these fluorescent designs allow the sharks to find each other 2,000 feet below the ocean’s surface, where most of the light that makes it down that far is blue.
14. They have personalities, just like us.
Last year, researchers discovered for the first time ever that sharks have undeniably distinct personalities. When put through a series of trials designed to test boldness, or propensity to take risks, individual sharks responded differently — and the shy sharks stayed consistently shy across all tests, while the bold sharks stayed consistently bold across all tests.
Shark behavior, they found, had nothing to do with chance and everything to do with personality.
15. Humans are the real killers, not sharks.
Our natural instinct is to fear sharks — and we understand feeling the need to exercise a bit of caution when in shark territory — but the reality is that we are sharks' biggest predator. According to a recent study published in the journal Marine Policy, humans kill around 100 million sharks every year.
Well, there you have it. If you didn't already know it, sharks are remarkable creatures that deserve our respect. They're technically our elders, having been on the Earth far longer than humans.
You can help protect these remarkable creatures. Shark finning — a cruel practice in which a shark’s fins are cut off and the body is discarded at sea to drown — affects up to 73 million sharks every year. Sign Oceana's petition to ban this inhumane practice and protect sharks around the world.