Seals, Subs, and Suits of Armor: Sharks That Eat Everything (Full Episode)

They're eating machines with a hunger that knows no bounds. Living or inanimate, nothing in the water is safe from the shark's insatiable appetite. For more and more and more. Dive into a world where absolutely nothing is off the menu. This is the ravenous realm of the sharks that eat everything. Before Mount Everest, before dinosaurs, even before trees, for nearly half a billion years, sharks have been prowling our planet in search of their next meal. But how did these fearless fish outlive five mass extinction level events? By eating whatever they can, whenever they can. And that means the strangest things end up in their powerful jaws. Even humans. The clear blue waters of the Florida Keys are filled with 600 species of fish. It's a fisherman's paradise. And 50 feet below the surface, 23-year-old spear fisherman Parker Simpson has just nabbed a large black grouper. But before he and his diving buddy can even head to the surface, Parker has a terrifying realization. Something big is circling nearby. Like leopards of the sea, reef sharks are agile, curious, and can deliver a deadly bite. Reef sharks usually hunt in packs and feed on smaller fish around coral beds. But in open water, they can become aggressive. Parker catches sight of a fast-moving eight-footer. Before he knows it, the shark strikes at breathtaking speed. Instead of snatching the grouper, the shark mistakenly munches on Parker's leg. If the pain of a gaping wound in salty water isn't enough to worry about, the attack severs Parker's tibial artery. There's blood in the water, potentially attracting nearby sharks. While it's a myth that sharks can smell one drop of blood from a mile away, their nostrils, known as narys, can smell one part per 10 billion, which is like a drop of blood in an Olympic-sized swimming pool. Parker scrambles back onto the boat and realizes the full extent of his injuries. That single reef bite tore through Parker's skin, fat, and muscle, all the way to the bone. He's lost more than two pints of blood. It takes three hours of surgery and 56 stitches to mend. This harrowing ordeal isn't isolated. Seems the more often humans get between sharks and their usual prey, the more often we pay the price. Off the coast of Fort Lauderdale, Florida, Carlos Lang and his friends spend the day diving and fishing, until he's attacked by a very aggressive nurse shark. An adult nurse shark can grow up to 14 feet long, and it has thousands of serrated teeth, so you can imagine just how much damage it can do. With teeth like a cheese grater and a cavity in their throat that sucks food in like a vacuum cleaner, they can turn flesh into hamburger. Lucky for Carlos, this juvenile nurse shark attacks with the power of a dust buster. But like a full-grown adult, it simply refuses to let go. It may have been attracted to the fish that Carlos had speared, but got a piece of Carlos instead. The young shark eventually swims off in search of something easier to eat. Oh my god, you're so lucky, that's all it was. Humans aren't the only ones in the line of fire. With voracious sharks prowling in all five oceans, it seems nothing in the water is safe. Because for sharks, he who eats the most wins. Sharks don't have hands, so they often use their mouths to investigate, and so when they encounter something that they're unfamiliar with, they might end up mouthing or biting that object. That impulse to bite before thinking has led to the most unlikely objects being retrieved from the guts of tiger sharks. License plates, tires, rubber boots, a fur coat, a full suit of armor, a chicken coop with the chickens still inside, a bag of money, even TNT and grenades. Most big sharks, like great whites, bite their prey, let them bleed out, but tiger sharks swallow their prey whole for the most part. And they're known as the trash cans of the sea because they will eat anything. So in a world in which nothing is saved from a shark's inquisitive eating, it's a good idea to keep hands and feet inside the vehicle at all times. Mossel Bay, South Africa. The waters off this harbor town are teeming with sea life. That's why these German tourists are on the lookout for captivating sea creatures, like these Cape fur seals. Weighing up to 800 pounds each, these marine mammals are the ideal meal for the largest predatory fish on Earth, the great white. For sharks, the key ingredient is fat. They use this fat to travel great distances or maintain their optimal body temperature, and recent studies indicate that great white sharks most likely eat a seal every three days. An inflatable pontoon boat filled with tourists, adrift in the center of great white hunting grounds brimming with their favorite meal. This is the perfect recipe for what happens next. Rather than feasting on seals, this hungry shark chomps down on the inflatable vessel. It thrashes and tears, easily puncturing it with any one of its five rows of razor-sharp serrated teeth. The boat immediately begins losing air and gaining water. While the great white's intention may seem clear, to capsize the boat and devour everyone on board, sharks simply aren't that strategic. Sharks are primitive animals and act on instinct alone. They attack what moves and try to eat it. They don't make the logical connection that they can sink a vessel and eat whatever tumbles out. With his vessel shredded and now listing, the tour operator makes the wise decision to hightail it back to shore while he still can. The cost to repair his shark-bitten boat? Nearly $3,000. Living to tell about it? Priceless. Sometimes it's not if a shark tries to eat your boat, but what part of the boat that separates horror from hilarity. In the waters surrounding the Bahamas, 40 different species of shark dine on basically whatever they want. Or at least they try. This four-foot lemon shark has clamped onto a boat motor and refuses to let go. Even when the skipper tilts the motor up and out of the water. But what would possess a normally non-aggressive species to try to eat something so inedible? Sharks can sense minute electrical pulses from their prey's muscle contractions with an organ called the ampullae of Lorenzini. Hundreds of holes in its snout filled with a jelly-like liquid. The engine emits an electrical field, possibly triggering this hungry shark to think it's prey. And there's only one way for a shark to know for sure. Take a bite. Or try to. Biologists believe that some sharks, like great whites, are more likely to snag their prey on the surface. But six-gill sharks rarely leave the ocean depths. So it's really not an option. These massive 18-foot predators, so named for having one more gill slit than other shark species, spend most of their days at depths of 4,000 feet and more. Prehistoric sharks had six gills, so the six-gill sharks today are likely more closely tied to these ancestors. Six gills usually live out their lives without ever encountering humans or human contraptions. So when a homemade sub trespasses on their turf, it demands closer inspection. Much closer. When ramming doesn't send the interloper swimming in the opposite direction, the six gills turn up the aggression. Attempting to eat the sub. That squeaking is the sound of the shark's teeth scraping against the hull. With nearly 2,000 pounds per square inch of pressure on this tiny sub, the pilot knows that one little puncture could lead to a disastrous implosion and soon heads for the safety of the surface. Not all prey is fortunate enough to have inch-thick glass and hardened aluminum separating them from the shark pursuing them. Palm Beach, Florida. Coast Guard Captain Ben Chancey hooks a grouper while fishing from his small plastic kayak. Got him. I had the Goliath grouper on first. It ate my bait. Then it pulled the rod out of my hands. That's when Ben's casual fishing adventure turns into a terrifying struggle for survival. For some reason, the Goliath grouper spit at my bait and then a bull shark ate it. Ben's no longer reeling in what he hoped would be tonight's dinner. Now he's hooked into one of the ocean's most aggressive killing machines. The bite force of a bull shark is the strongest of any shark. Stronger than the white or the hammerhead. 1,300 pounds of force. It's got 50 rows of teeth, seven in each row. So this mouth of 350 teeth. Ben has no choice but to continue the fight. But the bull has had enough. My first thought was, I'm going to jump back in the kayak. My second thought was, I still have my flip flops on. My third thought was, I have a giant shark underneath me and I need to swim back to the boat as fast as possible. Ben scurries to safety without his boat. Or his flip flops. It's not shocking that a tiny plastic kayak can't protect us from a shark's powerful jaws. But steel bars surely can. Or can they? The crystal clear waters surrounding Guadalupe Island make it easy for great whites to see what they're eating. And for divers to watch them do it. From the relative safety of an aluminum cage. First developed by legendary ocean explorer Jacques Cousteau, cages like this are designed to keep sharks out. But some sharks, like this 14-foot female great white, didn't read the instructions. She ignores the bait intended to keep her in camera range and opts to chomp down on the metal bars instead. The horrified divers are inches away from ending up inside her three-foot wide mouth. While most sharks swim away after taking an exploratory nibble, this great white simply won't give up. Research has shown that baiting large predators may condition them to associate humans with food and like us, they get aggressive when they expect to be fed. She rams the boat with her nose and then turns her attention back to the cage full of divers. The eyes are a sensitive part of the shark's body. So when attacking prey, white sharks will roll their eyes back in order to protect them. That's the telltale sign that she's going in for the kill. She clamps down on the cage with enough force to tear off a human limb. And just when the divers begin to think this may be their last dive, this frenzied great white turns tail in search of an easier meal. But some sharks take their cage rage a little too far. On this visit to Guadalupe, a diver has climbed down into a cage ready for some face time with a great white. The boat crew above begins baiting the waters, leading the ravenous sharks closer and closer until one powerful great white lunges for a hunk of chum and ends up inside the cage with the diver. Sharks aren't just blinded when they bite down on prey, they cannot swim backward. With nowhere to go but forward, the shark thrusts through the metal bars. The crew watches in horror. One of their own is trapped in a box with a 2,000 pound eating machine. And there's nothing anyone can do. After 23 terrifying seconds, the shark thrashes free, leaving a trail of blood. But whose blood is it? Panic sets in. Then, after what seems like an eternity, the diver emerges. Miraculously unharmed and walks away with one crazy fish story. Researchers have a few theories about why sharks get crazed around cages. Maybe it's more about the metal than the meat inside. When metal is in seawater, it sheds electrons, forming what we call a galvanic electric field. And that could stimulate a shark's electro sense, causing it to investigate. And when metal is on the move, it can really grab a hungry shark's attention. This whiny underwater research drone off the coast of Western Australia is just asking for trouble. In a flash, a 14-foot great white attacks from out of nowhere. Great white sharks can swim up to speeds of 35 miles per hour. Once they spot a target, they use a burst of speed to surprise their prey, while simultaneously trying to bite it in half. For sharks, the oceans are all-you-can-eat buffets. But sometimes, the dinner tables get turned. Newport Beach, California. Whale watchers spot some intense splashing nearby. Looks like a thresher shark has caught itself a sea lion. Threshers are keen fighters with the longest tails of any shark species, which they use to slap and stun their prey. I have been caught by a thresher shark tail, and it is a significant experience. But as the tourists get closer, they realize the shark isn't the one in control here. This 100-pound thresher shark has literally bitten off more than it can chew, attempting to eat a sea lion twice its size. California sea lions often predate on small fish and squid, but they are known to also feed on sharks, generally preferring their highly fatty and oily livers. Don't let the cuddly faces fool you. Sea lions are intelligent, powerful adversaries with the jaw strength of four dobermans. This time, the hunter has become the hunted. Like all sharks, thresher sharks are born and are independent of their mothers and fathers, and therefore, they are on their own to learn how to hunt as well as how to protect themselves. Since sea lions' mouths aren't big enough to swallow sharks whole, they fling their prey from side to side, ripping off mouthfuls of flesh, giving these whale watchers a gruesome show they never expected. Even small prey can occasionally ruin a shark's plan for its next meal. Off the coast of New Zealand, scientists studying deep-sea animal diversity have lowered bait onto the ocean floor, and a small hagfish moves in for a nibble. This blind deep-sea creature is also known as the snot eel, for reasons that are about to become obvious. A shark species known as the northern spiny dogfish lurks nearby. Spying what appears to be an easy takedown. These New Zealand natives may not grow larger than three feet, but they do pack a punch. Unlike virtually all other shark species, dogfish sharks have venom that coats their dorsal spines. The hungry shark confidently clamps down, but the hagfish has its own secret weapon. It instantly releases a mucus-like substance from specialized pores running along the length of its body. The sometimes fatal slime fills the shark's mouth, causing it to gag and recoil. Though hagfish slime might seem gross, it is actually scientifically interesting. It is made up of strands that are actually stronger than nylon and thinner than a human hair, and takes a really long time to dry out. Surprisingly, even after 450 million years of evolution, sharks are still attempting to swallow these slimers, despite the unappetizing aftertaste. Some scientists believe sharks develop their incessant taste for blood while still in the womb. Some sharks exhibit a really interesting trait called interuterine cannibalism, where the largest embryo will actually consume its brothers and sisters to ensure its own survival. For baby sharks aggressive enough to survive, that ruthless rivalry plays out for the rest of their lives. Like here, back in the Florida Keys, home to the smallest member of the hammerhead family, the bonnethead shark. This is the only shark species known to eat plants as well as animals. And this timid little shark's big appetite has gotten him hooked. While it's impossible to detect with the naked eye, it's actually sending out a distress signal, warning other sharks of danger. A shark caught on a line sends irregular pressure waves that can travel up to half a mile through the water. But sharks are born opportunists, so the bonnethead's call for help is about to backfire. It's like a dinner bell to predators in the area. Like this seven-foot, 400-pound bull shark. Named for its recognizable snout and its habit of head-butting prey, the bull shark ranks as one of the most aggressive species on the planet. And this one is zeroing in on its smaller, distant cousin. And just like that, it's over. Well, half over. Minutes later, the bull shark swoops back in to gulp down the rest of its kill. The fossil record tells us that sharks have been eating their own kind for 300 million years, just like in the womb. You don't have to travel far to witness that ancient cannibalism firsthand. Just up the coast near Miami, these anglers are enjoying a day fishing for tarpon, a game fish that grows to over eight feet. Suddenly... That's a bull shark, too. He's got something. One of the fishermen accidentally hooks a small bull shark, setting off a feeding frenzy no one saw coming. Oh, look at the shark trying to eat this shark! Holy s***! You've heard my language, but holy s***! The bull shark just became bait for an even bigger bull. Two more sharks swoop in to snatch up the scraps. A little farther up Florida's Atlantic coast is Port St. Lucie. The waters here are often full of blacktips, easily identified by the dark coloring at the peak of their dorsal fin. This is the shark most likely to bite humans, as they often migrate through shallower waters. These kayakers notice something strange below the surface, so they drop a camera into the water and find a four-foot blacktip bitten in half, still alive. Whatever ate half this shark is very big and most likely very close by. Attacking prey and biting the tail has two major benefits. It protects the predator from the toothy end of the prey and also prevents the prey from being able to escape after the attack. With the blacktip incapacitated, an eight-foot bull suddenly emerges from the depths to feast on his fellow shark. And it's not alone. Larger bull swoops in to steal the leftovers. Even more savage shark-on-shark action plays out off Australia's gorgeous Gold Coast. Beachgoers are drawn to these idyllic waters. So are some of the world's biggest shark species, like tigers, hammerheads, makos, even great whites. Officials need to keep those giant jaws away from the beach. So they hatch a plan. They set baited hook lines to lure the predators further offshore. But this attempt to make the beaches safer has the opposite effect. We're about a mile offshore and pulled up to this line and you can see that it had been tangled up. The float had a lot of weight put on it. That's when locals make a horrific discovery. Large sharks are surfacing in pieces, bearing massive wounds that could only be made by even bigger sharks. City officials have inadvertently created a massive shark smorgasbord, attracting a variety of deadly predators to decimate their own kind. It's not just one rogue shark attacking other sharks or even one species of shark attacking other sharks. It's lots of different sharks turning on each other. There's no mistaking that fatal signature. Evidence that even great whites will try to eat their own. And scientists are trying to prove it. Researchers in South Africa are studying the contents of sharks' stomachs to find out who's eating whom. Along the South African coast, in great whites, bulls and makos, up to 60% of their diet consists of smaller sharks. That's right. The majority of the South African shark's diet is other sharks. But is it just larger sharks cannibalizing their smaller siblings? For now, there's just one way to find out. This nine-foot great white was found snared in a fishing net. Here's the stomach. Certainly something interesting inside. Feels very hard, flat. Feels like a fin. It's very definitely a fin of a large shark. Something in the region of eight to 10 feet, which is almost the same size as this white shark. But as we've seen, sharks aren't satisfied with just chowing down on their relatives. Not as long as the oceans are chock full of other delicacies. Above the surface, the Pacific waters around Guadalupe Island appear warm and tranquil, belying what lies beneath. A massive school of frenzied sardines tightens its formation. Danger is near. When they perceive a threat, sardines will swim together, tightly bunched in the same direction to avoid being eaten. The source of the sardines' panic glides into view. An eight-foot salmon shark. The sardines' attempt to confuse the predator backfires. They've simply made the shark's job easier, gathering all its favorite snacks into a single swirling sardine smoothie. Many shark species and dolphins share a taste for these small oily fish for the same simple reason. It's all about the fat. They may be small, but sardines have a high variety of fats, making them a staple for sharks. While oil-rich sardines may be best for their diet, sharks, like humans, occasionally opt for convenience over nutrition. 25 feet above the frenzy, an unsuspecting juvenile black-footed albatross lands on the ocean's surface to rest its still-developing wings. While its bony body is much lower in fat than the sardines', the albatross is almost literally a sitting duck. In an instant, a tiger shark strikes. The desperate bird instinctively pecks at the shark, but its tiny beak is no match for the tiger's massive mouth. Also like humans, sharks occasionally allow their appetites to get the best of them. In scenic Mozambique, Southern Africa, the carcass of a 30-ton humpback whale washes up on the beach. Soon, dozens of sharks brave the shallows to feast at this all-you-can-eat blubber buffet. Whale carcasses provide an opportunistic windfall for sharks, providing enough food that several sharks can feed on them at once. The temptation is too great, and one brazen 13-foot tiger shark pushes to the front of the line, beating itself in the process. The tiger shark struggles to stay submerged. We don't know exactly how long a shark can survive in shallow waters. Sharks are fine-tuned creatures. If they get dehydrated, clots would form in their bodies, and the muscles that they use to swim would stop working. This could easily end up being this shark's last supper. Just when it appears the tiger has traded his life for an easy meal, a large wave pulls it back to sea, where it will continue its eating spree elsewhere. But there's another super-powered species that's famous for going really big, sometimes too big. St. Lucia, South Africa, home to one of the continent's largest tidal wetlands, where freshwater and saltwater combine in warm, clear shallows. While other sharks wouldn't be caught dead outside the salty ocean, one species likes to mix it up. Bull sharks are one of the only sharks that can survive in both saltwater and freshwater. Through a process called osmoregulation, they can increase or decrease the amount of salt in their bodies. So this notoriously aggressive predator can hunt beyond the confines of the ocean, making the bull shark lethal to sea creatures as well as land animals alike, like wild dogs, rats, and antelope. Occasionally, they even take on one of Africa's deadliest predators, a land dweller with the greatest bite force of any mammal on the planet. Nope, not this one. Or this one. That's right, this one. The hippopotamus's jaws open 180 degrees and have a bite that can snap a 10-foot croc in half. St. Lucia is home to the largest hippo population in South Africa, where they live in family groups called bloats. But today, a voracious predator lurks just beneath the surface. They're gonna need a bigger bloat. It's no surprise this brazen bull found his way upstream to these massive creatures. Hippos feed on grass, and their dung attracts fish. These fish could potentially attract bull sharks. The shark begins to move in. Mother hippos spend years raising their calves, and they are very protective. These moms have circled the wagons. The bull shark darts towards a hippo, attempting to deliver its trademark move, a hard-hitting headbutt. But despite their doughy appearance, hippos are almost entirely muscle. The giant hippos fight back. Seems taking down prey the size of a car is just too risky. And the bull moves on in search of its next, less challenging meal. On the other side of the hemisphere, in Australia's Prince Regent River, bull sharks share the briny waters with another dangerous neighbor, able to thrive in both salt and fresh water. Saltwater crocodiles are the largest living reptile and lay claim to the strongest bite of any animal on the planet, a whopping 3,700 pounds per square inch. For comparison, a full-grown male lion bites with only 650 pounds of force. With jaws that destructive, saltwater crocs, or salties, as they're called, have been known to feast on everything from crabs to cows. And every once in a while, a bold bull shark trespasses into croc country to compete for food. Tourists are tossing fish to this 17-foot-long saltwater crocodile, and this croc doesn't like to share. Just as the salty snaps at its snack, a bull shark races in for the steal and ends up getting eaten instead. It might seem hungry sharks don't stand a chance against their river rivals. Not so far away, in Australia's Adelaide River, lives the big daddy of them all, an 80-year-old 18-foot saltwater crocodile named Brutus. While Brutus looks invincible now, this wasn't always the case. The height of a mature saltwater crocodile is nearly bulletproof, but when it's younger, with thinner skin, a bull shark could bite through it. Locals believe a bull shark stole Brutus' front leg when he was young, and it seems Brutus still carries a grudge. When a bull shark slips into steal from Brutus' plate, these rare photos tell the whole gruesome tale. Moving in bursts of 20 miles per hour, Brutus easily snags the thrashing bull shark. And when he drags the breathless shark onto shore, this dinner date is over. On the other side of the globe, in much colder climates, lives an unusual species that scientists think may also have a taste for big game. Meet the Greenland shark. These 3,000-pound, 24-foot long prowlers of the deep have the longest lifespan of any vertebrate on Earth, at least 250 years. Which means this particular shark could have been feasting during the American Revolution. Living in cold water environments and having a slow metabolism enables Greenland sharks to live for an extremely long period of time. With so much time to kill, this species has the opportunity to expand its palate. Greenland sharks are both active predators and scavengers, and scientists have found reindeer and even polar bear parts in their stomachs. But how are deep-sea sharks sinking their teeth into land-roaming predators like polar bears? Scientists speculate that climate change is forcing polar bears to spend more time in the water going from iceberg to iceberg. That can make them potential targets for large sharks. Especially for a shark with plenty of time to wait for its next meal to slip into the water. On the flip side of the menu from rare mammals that are easy to catch are the abundant mammals that aren't. Of all the prey on planet Earth, none must be as enticing and aggravating for sharks as the dolphin. High in fat and usually found in the same waters, dolphins aren't just better swimmers, they're more strategic. If a hungry shark tries to dine out on a sick, slower dolphin or even a young calf, other dolphins cancel that reservation. Dolphins live in groups called pods, and the pod will usually surround the weaker dolphin to protect it from sharks. But when a shark catches a dolphin swimming solo, the shark's odds increase. But so does the competition. In Smoky Bay, South Australia, these oyster fishermen are about to witness a dolphin dinner firsthand. This grey white has successfully snagged its next meal. Or so he thinks. A second great white is muscling in. And just to make sure it's not missing out on another tasty tidbit, it drops the dolphin to bite the boat's motor. Which is when the fishermen decide it's time to leave the shark to eat its dolphin in pieces. It's just another meal half a billion years in the making for the sharks that eat everything.