11 Jaw-Dropping Facts About Sharks

Sink your teeth into these.

Each year, millions of people tune into Shark Week to learn more about some of the most amazing fish in our oceans. If you're having a hard time waiting all day for the new show to start on Discovery, don't worry: A Plus will also be offering shark-related content all week long to help you curb those shark withdrawals.

There is so much information about every species worth celebrating, but these are 11 of the most incredible facts about sharks:

1. Sharks have been on the Earth longer than trees.

Sharks first evolved around 400 million years ago; 50 million years sooner than the first tree showed up. Sharks also pre-date dinosaurs by 170 million years, mammals by 205 million years, crocodiles by 150 million years, and flowers by 275 million years!

2. Sharks reproduce really, really slowly.

Human pregnancy is nine months long, but that's nothing compared to some sharks. The elusive common frilled shark takes a staggering 3.5 years to develop its young. The gestation time for the spiny dogfish is about 2 years. Many other species take between 1-2 years before giving birth.

While this long gestation does mean that the young sharks are more well-developed and better able to fend for themselves, it is also a huge challenge for conservationists, because it is harder for shark populations to recover their numbers.

3. Sharks have extremely healthy teeth.

Because many sharks are completely dependent upon their teeth to catch prey and survive, it's important for them to have a reliable set of chompers. Sharks can have several rows of teeth which are easily shed and replaced with new ones. Because of this feature, it's not a big deal if they lose a tooth while hunting prey.

Even with the ability to quickly regrow teeth, scientists discovered the teeth are covered in natural fluoride, which helps them resist decay and stay healthy and strong. 

4. Sharks are shockingly good at finding a meal, thanks to electroreceptors.

Electroreception is an important sense that sharks use to understand their surroundings. Their snouts contain specialized features, allowing them to interpret the salt water's electrical conductivity. When something alters that conductivity, like the presence of blood from a wounded animal, sharks are able to pick up on it and find a meal.

5. Sharks have REALLY thick skin.

Because males tend to bite during mating, females have evolved to have thicker skin capable of standing up to those nips. 

Sharkskin isn't covered in normal fish scales; sharks have something called dermal denticles, which are somewhat tooth-shaped and covered in ridges, making sharks more hydrodynamic. These scales have inspired swimsuits for elite swimmers, but there is a debate about how much they improve performance.

6. The whale shark is currently the largest species of shark on Earth.

Whale sharks are currently the largest species of shark on Earth, growing to be 40 feet long. These filter-feeding gentle giants aren't the biggest shark species ever, though. That title goes to Megalodon, the prehistoric shark that measured up to 59 feet long and went extinct about 2.6 million years ago. (Despite what you may have heard on mockumentaries, megalodon absolutely does not still live in the ocean.)

The smallest shark in history is the dwarf lanternshark, which lives in the Caribbean Sea. Fully grown adults measure a mere 8 inches. Awww...

7. Thresher sharks use their tails as weapons.

We all know that great white sharks hunt by chasing down their prey and chomping down with their razor-sharp teeth and powerful jaws, but not every shark hunts in the same way. The thresher shark whips its long tail at prey. If it hits, the impact on the prey varies from being stunned long enough to be eaten to getting completely ripped to shreds.

8. Shark attacks on humans are extremely rare.

Sharks often get pegged as dangerous man-eaters, but they don't pose as much of a risk as many people think. Out of the hundreds of millions of people who swim in the ocean each year, about 50-75 people are bitten by sharks. On average, only 6 of those encounters are fatal. 

Those deaths are tragic, of course, but if sharks were really out to get humans, that number would be exponentially higher. By the numbers, humans are more likely to die from falling coconuts (150), dogs (10-20), or falling icicles (24+).

Besides, what sharks do to us is nothing compared to what we do to them...

9. Humans kill up to 100 million sharks every year.

Humans are responsible for the deaths of 100 million sharks every single year, according to a comprehensive 2013 study. This number may seem unrealistically high, but there are over 400 known species of shark in our oceans. Most of these sharks are killed by commercial fishing vessels that accidentally catch sharks in their nets or on their lines.

About one-quarter of all shark species are endangered, with some down to 50 percent of their historical numbers. Declining populations coupled with their long reproductive cycles make it difficult for the numbers to rebound. Thankfully, many countries have passed legislation in recent years to help protect sharks.

10. The creator of 'Jaws' regrets the role his work had on populations of great whites.

Peter Benchley wrote a novel about a shark that brought death and tragedy to an island town. Since the film adaptation of Jaws in 1975, great white sharks have become viewed as the ultimate predator, which made them a target for trophy fishermen who wanted to slay the beast, Moby Dick-style. This caused a massive decline in great white populations.

After seeing the devastating effects Jaws had on sharks, Benchley became an outspoken advocate for shark conservation, noting that an updated version of his novel would likely feature the shark not as the aggressor, but the victim.

11. The oceans are better because sharks are there.

Sharks are apex predators, which means they are crucial for keeping marine ecosystems in balance. Without them, the populations of other fish species would grow uncontrollably, having catastrophic consequences on the rest of the food chain. This has the invaluable effect of keeping oceans healthy and seafood sustainable.

While it's impossible to put a dollar amount on what that is worth, there is a clear economic benefit to having healthy, balanced ecosystems. Sharks might have value for their meat or fins, that's nothing compared to how much they are worth alive. A single shark could fetch $100-200 for its meat and body parts, but if kept alive, a single shark that is part of a robust population brings in almost $2 million in ecotourism benefits during its lifetime.

In other words: we need to protect our sharks.

Don't forget to check out our other Shark Week coverage:

Celebrate 'Shark Week' With This Fin-tastic Drinking Game