For the next week, it's all sharks all the time on Discovery. 

Yes, Shark Week is back. 

From August 12-16 the cable network will dedicate its programming to non-stop footage of America's favorite animal predator.  

In honor of Shark Week's 25th anniversary, we compiled 25 facts about sharks and the event from Discovery and National Geographic.

While enjoying shows "Sharkzilla,""25 Best Bites," and "How Jaws Changed the World," see how much do you know about the ocean's deadliest creature and the event that takes place every year on Discovery.

Do you know the largest shark, the rarest sharks, and the odds that you'll be eaten by one? 

Before sitting down to enjoy Shark Week, test your shark knowledge. 

Starting in 1988, Shark Week is the longest-running cable TV programming event in history.

1988: The first Shark Week included ten programs including "The Shark Takes a Siesta."

Sharks are older than dinosaurs! They were swimming around the earth more than 400 million years ago–200 million years before dinos.

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Until now, even the most highly-skilled wildlife cameraman have been unable to capture a Great White shark leaping straight out of the water from a bird's-eye view.  

A mission to get the "impossible shot" was documented in Discovery Channel's Shark Week series. We've pulled out the highlights.  

To get the "impossible shot," Shark Week veteran Andy Casagrande and his team headed to Gansbaii, South Africa, known for its dense population of Great Whites.

Watch video clips here > 

The objective: To get a never-before-seen view of a Great White leaping vertically out of the water in what is called a "Polaris Attack."

Watch video clips here > 

The first overhead view of a Polaris breach was captured by the Shark Week film crew in 2001. But researchers have been chasing after one particular angle for more than a decade.

Watch video clips here > 

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A two-month fishing expedition to the Indian Ocean has turned up hundreds of strange deep-sea sharks, and several are likely new to science.

At least eight new species could be among the fishy haul, said Paul Clerkin, a shark ecology graduate student at California's Moss Landing Marine Laboratories.

Clerkin joined the commercial fishing venture in March and April of this year, in hopes that the vessel's massive trawling nets might pluck sharks from the deep sea. He was not disappointed.

"I tell people I have a ton of sharks, and they keep thinking I’m joking," Clerkin said. "It was an actual ton. I brought back 350 sharks." [See some of the sharks]

The sharks were caught as bycatch from depths of approximately 6,500 feet (2,000 meters) from a region of undersea mountains, or seamounts, about a week's journey south of the island of Mauritius.

Day after day, the ship's nets brought up dozens of bizarre sharks from the deep — some dainty, some enormous, nearly all of them rare or entirely new species.

"They don’t look like the classic great whites you'll see on Shark Week," Clerkin said. "I think they're more interesting." Weird features abound: knifelike snouts, moonlike eyes and at least one shark with a curved, serrated spine emerging from its back.

Among the largest was a false catshark, a pointy-faced fish about 10 feet (3 m) long. Although it's a known species, it's a notoriously elusive one.

"It was exciting because I knew they were really rare, and the chance of seeing them was pretty small," Clerkin told OurAmazingPlanet. Yet after a while, he said, he began to think the species isn't nearly as rare as the literature suggests.

"We actually caught a lot — close to 35," he said, adding that it's likely humans simply haven't explored the parts of the ocean where false catsharks live. "I think it shows there's a lot we don't understand about sharks," he said.

Clerkin is taking between 80 and 90 measurements from each shark, a time-consuming task, and is also sending off genetic samples for comparison.

If the any of the species are indeed new, Clerkin gets to name them. He said he'll likely name some of the sharks for his science mentors. "And maybe I'll name one after my mom," he said.

Reach Andrea Mustain at amustain@techmedianetwork.com. Follow her on Twitter@AndreaMustain. Follow OurAmazingPlanet for the latest in Earth science and exploration news on Twitter @OAPlanet and on Facebook.

• In Images: The Fantastic Fishes of Shark Island
• Images: 17 Amazing Sea Creatures You've Never Heard Of
• On the Brink: A Gallery of Wild Sharks

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All this talk about Shark Week has us interested in these prehistoric destroyers, so we decided to see what exactly makes these killers so intriguing.

With some help from Professor Mahmood Shivji, Director of the Guy Harvey Research Institute and Save Our Seas Shark Center at Nova Southeastern University, we found out that sharks have some super abilities you would not be amiss at comparing to those of a comic book superhero.

From super speed to incredibly fast healing, the over 500 species of sharks truly deserve the fascination that we have for them.

However, Dr. Shivji points out that despite these superpowers and the perceived ferociousness of sharks, very few have attacked humans. On the contrary the fishing of sharks for their fins by humans has brought many species to the brink of extinction.

The power to emit light and glow.

Superpower: Glowing bodies

The pygmy shark has light-emitting organs that make its skin glow. This tiny shark only grows to about 8 inches and uses the light as a form of camouflage, lighting up it's stomach to imitate the light that filters down through the ocean from the sun or moon above. Without the lights, it's body would block this light, and that would enable predators to see it from below.

The lantern shark has a similar ability, but uses its  30-minute bursts of light to communicate.

The power to heal remarkably fast.

Superpower: Fast healing

We tend to think of sharks as the ones giving out the damage, but they get injured too. So much so that they are evolved to be incredibly good at healing from wounds. Sharks have been observed to heal from serious external injuries extremely quickly, with major bites and gashes completely healing in just a couple of months.

One reason for this healing proficiency is that sharks constantly shed and replace parts of their bodies including their teeth and fin spines.

According to Dr. Shivji, the shark's ability to "heal very quickly from external wounds is remarkable."

The power of moving while sleeping.

Superpower: The real sleep "walkers"

It is a pretty common myth that sharks don't sleep and as cool as that would be it's unfortunately not true. Sharks need rest like everyone else, but the things that sharks can do while sleeping are pretty amazing.

Some sharks must constantly keep moving, so oxygenated water is always moving over their gills, so even when their sleeping they glide through the water.

Other sharks can lie on the bottom while sleeping, but do some odd things as well. Some of these awesome zombie-sharks actually keep their eyes open while their asleep, which has prolonged the misconception that sharks never sleep, Shivji said.

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This week we only have one animal on the mind: sharks. 

Discovery Channel'sShark Week has answered many questions about the marine mammal, but it's also raised a few basic queries.  

For some fast answers, we turned to the amazing crowdsourcing tool Quora where we found marine biologist Jan Husar (@janhusar).  

Below we've listed the question, along with our short answer based on Husar's complete response, also shown below.

Do sharks sleep?

The short answer: Yes. 

Husar: Shark do sleep, it seems all the creatures on the planet relax, sleep, even hibernate in same cases. For the shark species who have to swim to keep breathing the theory is that they sleep as couple of other such fish, they relax around half of the body and engage in some instinct mode. It was documented in some cases with the dolphins. However [for] the sharks who sleep on the bottom the questions really is when they sleep? They tend to just lay down for hours during day or night and seem to be more relaxing then sleeping with their eyes open. This is one of the many things we don't know about sharks, and why we should find out.

Do sharks get diseases?

The short answer: Yes. They do have strong immune systems, but it's only a myth that they can't get cancer or other diseases. 

Husar: They do, it is a general misconception that sharks can't get diseases or cancer, there is no scientific proof for it. In fact there is hardly any scientific proof that they are more immune than other fishes, it's more anecdotal than a real thing.

What are the best places to see Great White sharks in the wild?

The short answer: 

• America: Guadalupe
• South Africa: Cape Town and Port Elisabeth
• Australia: south-east coast

Husar: Depends on where are you in the world, in America it will be the Guadalupe, in South Africa the Cape Town and Port Elisabeth, in Australia the south-east coast. There is not only one special place to see great whites since they tend to circumnavigate the globe and you might find them on places where people think that white sharks do not live, for example the Mediterranean.

Are sharks capable of living in fresh water?

Short answer: There are at least a handful of species that live in fresh water. One shark, the Bull Shark, can live in both salt and fresh water. But most sharks are built to live in salt water. 

Husar: There are 5 known species in the genus Glyphis as true fresh water sharks and we know little about them. 

One species can both live in fresh and salt water. It is Bullshark, also known as Zambezi Shark in Africa (Since living in the vicinity of Zambezi River).  If you release a bullshark he could survive for quite some time, but other species cannot solute the concentration of salt in their system.

What has prevented other species of sharks to enter fresh water is simple, their blood is salty as seawater in their blood (with urea). Other elasmobranch species who enter fresh water are stingrays and sawfishes. Salt water sharks will not survive in fresh water.

What attracts sharks to blood?

Short answer: The smell. That's why sharks are attracted to fish blood, which has a different smell than mammal blood. 

Husar: It's sort of a smell sense, they are, however, attracted more to the fish blood than mammal blood, which in fact smells totally differently. You may check this out on the last year's shark week special, where in fact they tested it. There might be a slight change in this theory when the shark is used to eat marine mammals (like seals) however this is just a speculation.

What time of day do most sharks feed? 

Short answer: Most sharks hunt at night. But it depends on the kind of shark and its location.  

Husar: Depends of the vitality of the ecosystem in their habitat, the species, the part of the world they are in. But most sharks do hunt at night, especially when we are talking about attacking predators. You have to look on how sharks attack to find the correct answer, which is they attack in a way that they prevent most of the harm to them done by the attack. So it would be night, when other creatures sleep. But they will feed anytime they could but not hunt. That's why if you want to attract sharks on bait is easy, they follow their instincts for cheap meal, e.g. hurt fish, dying fish.

More Sharks

• Film Crew Finally Gets 'Impossible' Shot Of A Great White Attack

• 25 Awesome Things You Should Know For Shark Week

• Rare Video Of Whale Shark Stealing Fish From A Massive Net

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When we think of sharks, the picture we pull up is often that of the tremendous great white. But these big sharks aren't the only kinds out there. Sharks come in all shapes and sizes, some of them with crazy skills, special spines, and knifelike snouts.

To get a better idea of how many sharks there are out there, and learn more about the different species, researcher Paul Clerkin, a graduate student at California's Moss Landing Marine Laboratories, set out on a two-month fishing expedition.

"I tell people I have a ton of sharks, and they keep thinking I’m joking," Clerkin said in an interview with OurAmazingPlanet. "It was an actual ton. I brought back 350 sharks."

Some of them are completely new species that hadn't been discovered before.

He collected the sharks that the fishermen caught accidentally — called "bycatch"— while they were trawling the seafloor.

"As the fishermen trawl for their targeted catch, many other species are often caught unintentionally and result in incidental mortalities. The fishing vessel did not change its normal fishing practices to target the sharks, and they actually avoid sharks because most species have low commercial value and can damage the nets," Clerkin told us in an email. Clerkin "only collected sharks that were dead when they came out of the net, and any shark that was even slightly alive was immediately returned to the ocean without further risk to its health."

Here, he describes some of the weird sharks he found in his own words.

This is a new species of catshark. As you can see from the ruler in the picture the shark only gets a little over a foot long before they fully mature. Although they are small they might be important predators on the sea mounts (underwater mountains) they inhabit. This chubby little shark’s appearance greatly contrasts with the classic vision of the Great White shark.

In this picture I am working on deck with a false catshark. This species isn’t new but it is considered to be rare. I was extremely excited the first time we found one. As we caught more false catsharks over the trip I started to suspect these sharks are not as rare as previously thought. I think they just live in remote locations relatively unexplored by science. Although it is not a new species I gathered data and information on this shark that was previously unknown and will increase our understanding of this strange animal.

This picture was taken on the ship. It is a Gulper shark.

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Is a Great White shark's strike strong enough to kill a seal on impact?

Biologists attempt to find out by measuring the power of a shark attack as part of the Discovery Channel's "Air Jaws Apocalypse" episode.  

To determine whether a Great White shark's flying attack is powerful enough to kill a seal on impact, researchers head to Seal Island in South Africa.

Watch the video clip here > 

Nobody knows what a seal can withstand, but the team imagines that the force of a shark's strike from a depth of 100 feet is comparable to a human being hit by a car.

Watch the video clip here > 

The force of acceleration on a body is known as g-force and is measured in g's.

Watch the video clip here > 

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Of course VW turned a Beetle into a shark cage that drives on the ocean floor for the Discovery Channel's Shark Week.

Deutsch and MediaCom built this recognizable, subterranean shark cage as a promotion for the 25th anniversary of the best week of the year. (Seriously).

It turns out that the iconic Beetle shape is still recognizable and lovable, even with sharks swimming around it. We put together a slideshow breaking down how the VW Beetle shark cage was built.

Meet Luke Tripple. He's a biologist and loves swimming with sharks.

Luke challenged his team of engineers and biologists to create a submersible VW Beetle Shark Cage in just two weeks.

The team designed and built the shark cage from scratch, using the car's original design only as an outline for the water-bound Beetle.

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Discovery Channel's Shark Week might be bad news for seals, but it means great things for Beetles.

Last year, Volkswagen and Discovery transformed a Beetle into an underwater shark cage. Now the companies have partnered up again, and raised the stakes by turning the cage into a convertible.

"Calling it a shark cage is kind of tongue-in-cheek,"Luke Tipple, the shark wrangler and marine biologist in charge of driving the "car," told Business Insider. "It's pretty open."

But taking the top off isn't the only adjustment made on the car, which will take a subterranean road trip in Florida and the Bahamas surrounded by Caribbean reef, lemon, and tiger sharks.

"On top of creating a groundbreaking vehicle, this year we planned to make it fly," said Tipple, who is also an executive producer at What We Do Media. "We created a lift with ailerons in the front — it actually flies like a plane."

That means that rather than driving 15 feet underwater on the ocean floor, as it had last year, the VW flew through water that was 60 feet deep at 4 to 5 knots. It had three thrusters, instead of two, with 20 more pounds of torque per engine.

"If the vehicle fails, it will drop like a rock," said Tipple, who was behind the wheel. But he and VW execs weren't too worried.

"Well, we don't pile shark bait around him," VW advertising and marketing communications manager Justin Osborne told BI. "We aren't going to deal with a great white. We'd make the evening news ... not in a good way, though."

He said that when Discovery and VW first began its partnership last year, the company pitched various ideas for brand-integrated stunts. "A lot of them they threw out because it wasn't true to the science Discovery promotes."

The shark cage idea stuck.

"We were a little surprised — we didn't understand the popularity of Shark Week,"which now has a cult-like following, Osborne said. "People were starved for more content and behind the scene footage. They also wanted some more underwater scenes."

So now, through a highly planned social component, viewers can take a subterranean road trip with Tipple, seeing what he sees through 360-degree underwater cameras. 

"For me, I'm a complete gadget and gear geek," Tipple said. "I love looking at the controls of things and seeing how they work."

The Shark Week obsessed can watch the shark cage explore actual underwater shipwrecks and follow shark highways where the sharks feed and mate.

"This relationship touches every aspect of Discovery and all the entities of Shark Week," Discovery SVP of ad sales Harold Morgenstern added. "It was very natural for us to repeat a champion combination."

Meet Luke Tipple. He's a shark wrangler, marine biologist, and the driver of Volkswagen's convertible Beetle shark cage.

Don't worry, Tipple has had a lot of shark experience. His company, What We Do Media, pairs him with brands all the time. He even cut himself shaving — surrounded by bloodthirsty sharks — for Gillette.

Tipple drove Volkswagen's Beetle shark cage for Shark Week last year.

Shark Week!

Discovery Channel's wildly popular television series about one of the oceans' most powerful predators returns on Sunday, August 4, for its 26th season.

You can check out this year's episode lineup here.

In the meantime, enjoy these shark-y photos to get you even more pumped for the Shark Week premiere.

Veteran "Shark Week" filmmaker Jeff Kurr and crew capture Great White Sharks on camera in New Zealand.

Photographer Andrew Casagrande gets close to clamping a fin cam onto a Great White.

A Great White is seen up-close in New Zealand.

This special Sharkcam locks onto the signal emitted from a shark's tag and tracks its every move.

A large Great White shark cruises past the underwater cameraman at Guadalupe Island off the coast of Mexico.

SEE ALSO: Maine's Top Chef Shows Us The Right Way To Steam And Eat A Lobster

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Heather Boswell was only a teenager when she lost her leg to a shark. That was in 1994. And it was all recorded on home video. 

Boswell's harrowing shark-survival story, and others who suffered a similar trauma, are told as part of Discovery Channel's "Shark Week," which premieres Sunday, August 4.

Only a small percentage of shark species are considered dangerous to humans. In fact, more people die from bees, wasps, and snakes each year than sharks, according to the International Shark Attack file.

But run-ins between humans and sharks do happen — whether by accident or provoked.

All of these shark attack victims lived to tell their stories, but not without injuries.

Heather Boswell was 19 years old when she was attacked by a Great White Shark while swimming off the coast of Chile.

Watch more Shark Week clips here »

Boswell was working on a research ship, Discoverer, at the the time of the accident.

The attack happened as the young researcher and her crew members were swimming in the balmy waters of the Pacific Ocean, enjoying a day off from their environmental work.

Starting Sunday, Shark Week is upon us. 

In its 26th year celebrating all things "Jaws"-related, Discovery Channel packs an exciting line-up of shark educational programming, survivor tales, and celebrity appearances by Snuffy the Seal.

Here are 5 Shark Week events to get mega-excited for:

5.  Paul Walker makes an appearance.

"Fast and Furious" actor Paul Walker, who studied marine biology in college, will appear in the "Spawn of Jaws" special. Using state of the art tracking technology, a team of scientists — plus Walker — search for the elusive Great White shark breeding grounds. Tuesday, August 6, at 10|9C

4. Shark Attack mysteries solved.

Natural history producer Jeff Kurr — whose 2011 special "Air Jaws" was nominated for any Emmy — is back with "Great White Serial Killer." Kurr examines evidence from two fatal shark attacks near Vandenberg Air Force base in California to determine if the same shark is the culprit. Wednesday, August 7, at 10|9C

3. Scary-close video footage of sharks.

Discovery presents: The puppy cam for sharks. A robotic submarine films Great White sharks off the coast of Cape Cod, the setting for "Jaws." Highlights include close-up footage of a 17-foot Great White hunting seals, shot over five hours. Monday, August 5, at 9|8C

2." Shark After Dark" the talk show.

Comedian Josh Wolf hosts Shark Week's first late-night talk show, "Shark After Dark." The hour-long show features memorable clips from the last 26 years, celebrity guests and shark experts, and previews of next-day programming. Every Night, Beginning August 4, at 11|10C

1. "Top 10 Sharkdown" of the most ruthless sharks.

If you think Great Whites are old news, the "Top 10 Sharkdown" is for you. This countdown introduces the most dangerous sharks — and the ones you're most likely to encounter. There's a species whose cannibalistic young eat each other in the womb. Wednesday, August 7, at 9|8C

Here's the full Shark Week line-up.

SEE ALSO: VW Turned A Beetle Into An Underwater 'Flying' Shark Cage For Shark Week

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New York recently became the latest state to pass legislation banning the possession and sale of shark fins, a move to protect the marine predators.

Shark hunting and finning — the practice of removing a shark's fin and returning the maimed animal to the ocean to die — have had a serious impact on shark populations worldwide, with an estimated 100 million sharks killed each year.

Sharks are hunted not for their meat, but for their chewy, tasteless fins, which have been a Chinese status symbol since the Ming Dynasty, when it was cooked specifically for emperors. Today they are commonly consumed at Chinese weddings, banquets, and business dinners.

Since sharks are in the news (thanks, Shark Week!), we decided to take a look back at celebrity chef Gordon Ramsay's 2011 investigative report on the shark fin trade in London, Taiwan, and Costa Rica. You can watch the entire documentary here or on Amazon.

Ramsay was not only shocked at how the sharks were slowly killed, but discovered that the crew had hacked a fin off a shark and threw the body overboard. The crew told Ramsay it wasn't a big deal because "it was only one fin."

But because of the negative associations with shark finning, restaurant owners and managers clam up when they're asked about it. This London restaurant owner wouldn't even let Gordon Ramsay and his cameras in to see the soup and talk to customers.

So in an effort to understand the shark fin demand, Ramsay traveled to Taipei, Taiwan, where shark fin soup is served everywhere from corner cafés to fine-dining establishments.

Discovery Channel kicked off Shark Week on Sunday with a fake documentary about the Great White shark's prehistoric ancestor, megalodon.

Megalodons did at exist at one point. But the powerful ocean predator went extinct 2 million years ago.

The "documentary"— with fictional scripts and phony research — asks us to consider the possibility that megalodon is still roaming the oceans and toppling fishing boats. It upset many Discovery Channel viewers who were briefly convinced that megalodon is terrorizing humans today.

The ancient shark is long gone; however, the 50-ton beast could do some serious damage when it ruled the prehistoric seas.

Last year, the Shark Week team built a full-size model of megalodon, to see if it could hunt and kill giant whales.

You can see video on the Shark Week website.

At more than 60 feet long, megalodon — (literally "big tooth") — was the top predator in the ocean up until they went extinct two million years ago.

Watch Clip On Discovery Channel »

They were much larger than Tyrannosaurus rex. Megalodons weighed up to 100 tons, while T-rex weighed a puny 9 tons.

Watch Clip On Discovery Channel »

In fact, a T-rex would have been a quick snack for megalodon. Its head would have easily fit inside the gargantuan shark's mouth.

Watch Clip On Discovery Channel »

Discovery Channel is standing by its fake documentary about an ancient giant shark, Megalodon. The two-hour special, called "Megalodon: The Monster Shark Lives," aired on Sunday night to kick off Shark Week.  

Megalodon, a 60-foot-long relative of the Great White shark, is real. However, the creature went extinct 2 million years ago. The mockumentary used fake footage and storylines to convince viewers that Megalodon still roams the oceans today.

A disclaimer, confirming that the show was fantasy rather than fact, only ran at the end of the program.

It read: "None of the institutions or agencies that appear in the film are affiliated with it in any way, nor have approved its contents. Though certain events and characters in this film have been dramatized, sightings of 'Submarine' continue to this day. Megalodon was a real shark. Legends of giant sharks persist all over the world. There is still debate about what they might be.

Many Discovery Channel viewers felt duped and turned to Facebook and Twitter to express their anger. 

Michael Sorensen, the executive producer of Shark Week, defends the fake episode. He told FoxNews: “With a whole week of Shark Week programming ahead of us, we wanted to explore the possibilities of Megalodon. It’s one of the most debated shark discussions of all time, can Megalodon exist today? It’s Ultimate Shark Week fantasy. The stories have been out there for years and with 95% of the ocean unexplored, who really knows?”

Just a couple months ago, Animal Planet (also owned by Discovery Communications) received a similar backlash from viewers after it aired a fake documentary about mermaids. 

SEE ALSO: One Woman's Horrifying Shark Attack Captured On Rare Home Video

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The Discovery Channel's Shark Week got off to a less-than-stellar start this weekend with a two-hour piece devoted to Megalodon, a prehistoric giant shark that grew up to 60 feet (18 meters) long and had jaws powerful enough to crush an automobile. The only problem is that the show suggested these animals still exist, which is definitely not the case. Up to 70 percent of the audience may now think that Megalodon is not extinct, according to a poll from the Discovery Channel.

That's too bad, because there are tons of bizarre and completely true facts about sharks that are more arresting than fiction. And although humans have always been fascinated by sharks, we know surprisingly little about them.

One thing we do know is how important sharks are to ocean ecosystems, where they keep populations of midlevel predators in check; when they disappear, changes can ripple through the food web and even affect the presence of marine plants, studies have shown. But as many as 100 million sharks are killed each year for their meat and their fins, which are made into shark fin soup. This dish is considered a delicacy and is prized in China, despite evidence that it can contain high levels of toxins like mercury. [On the Brink: A Gallery of Wild Sharks]

Conservationists hope that if people knew more about how awesome sharks are, perhaps they'd be less likely to condone the killing of these creatures, which have been around for about 420 million years and have changed little since then.

On that note, here are some awesomely weird — and completely true — facts about sharks to sink your teeth into:

1.Even if sharks could brush their teeth, they wouldn't need to: Shark teeth are covered in fluoride, making them cavity-resistant. One 2012 study published in the Journal of Structural Biology found that sharks' enamel is made up of a chemical called fluoroapatite, which is resistant to acid produced by bacteria. This, combined with the fact that most sharks replace their teeth throughout their lives, means that sharks have excellent dental health. A gold star for you at your next dentist appointment, sharks!

2.The cookiecutter shark can take ice-cream-scoop-shaped bites out of other sharks, including great whites, which are many times larger. They also have been known to bite holes in cables and other materials used by U.S. Navy submarines, which has necessitated a switch to a fiberglass, bite-proof coating. [More Weird Shark Facts]

3.The skin of a female shark is much thicker than that of a male because males bite females during mating, said David Shiffman, a shark researcher and doctoral student at the University of Miami.

4. The Greenland shark, the slowest-moving fish ever recorded, has been found with reindeer, polar bears and fast-moving seals in its stomach, Shiffman told LiveScience. It's thought that Greenland sharks prey upon sleeping seals, which snooze in the water to avoid polar bears.

5. Lantern sharks can glow to disguise themselves in the deep ocean, emitting the same amount of light as that which is filtering down from above; this way, they don't create a "shadow."Velvet belly lantern sharks have glowing spines that may be used to ward off predators.

Email Douglas Main or follow him on Twitter or Google+. Follow us @livescience, Facebook or Google+. Article originally on LiveScience.com.

• Image Gallery: Great White Sharks
• Cyclops of the Sea: Pictures of a One-Eyed Shark
• Images: Sharks & Whales from Above

SEE ALSO: How The 60-Foot-Long Ancient Shark, Megalodon, Ripped Apart Giant Whales

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It's Shark Week, so we wanted to tell you about some of our favorite sharks.

My favorite is the cat-sized shark in the picture above — it doesn't look that intimidating, but its bite is quite fearsome.

It uses its razor-sharp teeth to take a huge chunk out of anything it can find — including other sharks, fish, dolphins, humans, and even electrical equipment in the ocean. The distinctive bites have been found in all kinds of fish and other sharks, and even a human has been attacked by the little guys.

The cookiecutter shark bites a victim, then with a circular sawing motion extracts a clump of flesh. Here's what the bites look like:

A recent paper out in Pacific Science earlier this year detailed the cookiecutter bites on a great white shark.

Here's what the shark looked like after the attack:

The shark's stomach glows, and it has a dark band around its neck that looks like a fish, which could be what lures other sharks to it.

Another great fact about the cookiecutter shark? It has the power to take down an entire nuclear submarine.

The fish's strange bite can get at the softer areas of the submarines, National Geographic's Ed Yong reports:

The fearless cookie-cutters have even disabled the most dangerous ocean creature of all—the nuclear submarine. They attacked exposed soft areas including electrical cables and rubber sonar domes. In several cases, the attacks effectively blinded the subs, forcing them back to base for repairs. They later returned, fitted with fibreglass coverings.

The attacks happened in the 1970s and the problem seems to have been taken care of, though in several cases the sharks did enough damage to the vessel's sonar equipment that the oils inside that transmit sound would leak out of the ship and break the equipment — the subs could no longer see what was around them, according to the ReefQuest Centre for Shark Research.

Nuclear subs obviously aren't all that tasty, but the sharks seem to bite just about anything — even research equipment in the ocean.

SEE ALSO:  These Rare Sharks Are Some Of The Weirdest Animals On Earth

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Does Megalodon still exist? 

71% of people think so after watching Discovery Channel's fake documentary about the massive prehistoric shark.

"YES! The evidence for Megalodon can't be ignored. This monster shark lives," the majority of responders agreed. 

(It's not clear whether these viewers are aware that the "evidence" presented in the film, including footage and interviews with scientists, was fake). 

The rest of viewers see eye-to-eye with scientists: Megalodon is dead. The shark went extinct roughly 2 million years ago after ruling the seas for about 15 million years. 

See the poll below:

SEE ALSO: One Woman's Horrifying Shark Attack Captured On Rare Home Video

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Megalodon was a humongous prehistoric shark that was 10 times bigger than a Tyrannosaurus rex and ate whales.

The marine beast first terrorized our oceans around 17 million years ago, according to a Discovery Channel "Shark Week" special about the predator.

In spite of Discovery's partly-fictionalized documentary— which asks viewers to believe that Megalodon is still alive — most scientists agree that Megalodon went extinct roughly 2 million years ago.

Consider us lucky.

With 276 teeth, each 7 inches in length, the film calls Megalodon's mouth "one of nature's most deadly creations."

Megalodon could crush a whale's skull, clamping down on its victim with more than 35,000 pounds of force, according to the film.

Below is a screen grab of a fossilized tooth from a Great White shark (left) compared to a fossilized tooth from Megalodon:

And here's a reconstruction of a Megalodon jaw, made by American zoologist Bashford Dean in 1909. An entire man can fit comfortably inside!

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When a dead shark was discovered in a New York City subway train Wednesday, some were quick to cry "marketing stunt." 

"Looks like a good promo for Shark Week on the Discover Channel,"MTA spokesman Kevin Ortiz told The Huffington Post.

Tongue-in-cheek tweets have also circulated about "Shark Week" connections:

And SyFy UK, whose American counterpart made "Sharknado," was quick to jump on the buzz:

Although immersive marketing stunts are the new normal, a dead shark is probably too dark even for the makers of "Sharknado."

Even speculations about "Shark Week," which is currently airing on The Discovery Channel, were in jest, Discovery executive vice president of PR Laurie Goldberg commented on the strange occurrence.

"Shark Week is all about conversation, so it deeply saddens us that someone would think that this was funny or in any way connected to our celebration of sharks," she said.

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