How Baby Sharks Survive in a Dangerous World (Full Episode) ｜ Baby Sharks

Sharks are big, fast, fierce predators. But in their first year of life, they are surprisingly vulnerable. To stay alive, they can walk out of water, live in rivers, and even eat their siblings, all in the fight to make it as a baby shark. Sharks are formidable hunters that have evolved over 450 million years. They are the most feared creatures in our seas. Great whites with the power to leap 10 feet into the air. Mako with speeds of over 45 miles per hour. But baby sharks don't start out this way. In fact, they're a target for predators, including other sharks. Around 80% of some shark species won't make it to adulthood. Adult sharks don't spend any time caring for their newborns. A baby shark is just another item on their menu, which is why some pregnant sharks, like this one, travel to shallow water to give birth, where big predators just can't go. Exactly where sharks are born is largely still a mystery. So this footage of a shark birth is extremely rare. Once born, many sharks remain in the safety of the shallows in areas known as nurseries, like this one, near tropical Orpheus Island on the Great Barrier Reef. The reef is home to more than 1,600 species of sharks. This blacktip reef shark was born just a few days ago, near the mangroves lining the shore. The above ground root system offers protection to baby blacktips and many other small animals as well. At around 20 inches in length, this young blacktip is a quarter of the size of an adult. Blacktips are able to swim from the moment they're born. They dart among the tangled roots in nature's playground. But there is no time to play when you're a hungry baby shark. Luckily, his mother left him a parting gift. Blacktips, like many shark pups, are born with extra fats stored in their liver, giving them enough energy to explore the deep water environment as they learn to hunt for food. Venturing into the shallow bay presents opportunities for a larger meal. At three months old, he's still quite small. But within a year, he'll double in length, four times the growth rate of a human baby. What he lacks in size, he makes up for in speed. Blacktips hunt with bursts of over 20 feet per second. He will spend his first 15 months hunting small fish, crabs, and octopus till he's big enough to travel out to the reef with the adults. Further south, in cooler waters, a bigger shark with a bad reputation gives birth on our doorstep. In estuaries and rivers where fresh water meets the sea, you'll find bull sharks. Bull sharks are deadly and the most versatile of all sharks. They are the only shark species that can move between salt water and fresh water. With special glands near their tail, they are able to regulate salt levels in their massive bodies. That means they can swim a little too close to home along beaches and rivers, making human encounters more frequent than with any other shark. But why swim in fresh water with a vast ocean to exploit? One reason is to give their babies the best chance of survival. Bull sharks choose shallow water estuaries to give birth to their young. Far from where any other shark species can go, a newborn bull shark is about as long as a human arm, less than three feet. From birth, they have the ability to live in fresh or salt water. But a receding tide can leave a baby shark trapped and in grave danger. Despite the safety of river systems, predators lurk, and baby bull sharks have few defenses. Here on Australia's central east coast, crocodiles are not a threat. But young bull sharks face other pressures like pollution and habitat loss, which is why Dr. Amy Smoothie is here to help track their movements. So these sharks are vulnerable at these early life stages. It's really important to understand their movements and behaviors so that we can learn about what type of habitats they're utilizing so that we ultimately can understand where they're going, when, and protect the sharks and their habitats that they're using. To catch and tag baby bull sharks, Amy and fisherman Troy Billen have been out setting lines early in the morning when the sharks are most active. Pregnant females come into the estuary to give birth late spring, early summer. We're not sure exactly how many sharks are in the estuary. But what we do know is that the Clarence River is a pupping area, and it's a nursery for bull sharks. As the sun rises, Troy and Amy begin to check the lines. Oh, yes, we have a bull shark pup. Oh, hello. There's a little male bull shark. And you can see that its umbilical scar that was present is still open. It's just starting to close over. So it's likely that this shark is being born a few weeks ago. What a beautiful looking fish. Male bull shark. Wonderful. Many people think of bull sharks as big, man-eating predators. However, they're not that. They're an apex predator that's incredibly important to keep a balanced marine ecosystem. He is 81 centimeters long, or 2 foot 8. Turning the young shark on his back puts him into a state of tonic immobility, making it easier for Dr. Smoothie to perform minor surgery. So right now, I'm just going to make a small surgical incision in the abdomen. I'm inserting the acoustic tag. Unlike a satellite fin tag, this small device is inserted internally. And we are able to identify the shark when it comes within 500 meters of a listening station. Satellite tags only receive data when a shark surfaces. But the acoustic tag lets Amy track the shark's movements with an underwater receiver. And it will work for up to 10 years. Previous tracking has shown baby bull sharks are incredibly active in estuaries, traveling more than 60 miles upriver. You are an important apex predator. And I hope I get to see you one day in Sydney Harbor. By following baby bull sharks as they grow, we can hope to understand how they use their environment and how bull sharks and humans can better coexist. By about five years old, this shark could pose a threat to smaller baby sharks. Luckily, he'll be big enough to expand his hunting ground out to sea. Further north on Australia's east coast, the babies of another shark face cannibalism in the womb. The sand tiger shark is one of the most ferocious looking sharks. Up to 10 feet long and over 300 pounds, these adults are big and intimidating. Thankfully, sand tigers are extremely docile toward humans, often referred to as the Labradors of the sea. Sand tigers give birth only once every two years. And they never birth more than two pups at a time. They have the lowest reproductive rate of any shark. This makes them particularly vulnerable and their babies especially precious. One of the most important breeding grounds on the planet for the sand tiger shark is here just off Rainbow Beach in Queensland, Australia, a place called Wolf Rock. Volcanic pinnacles jut up from the sandy bottom, creating a sheltered oasis in a blue desert. It's a biodiversity hotspot for fish, rays, and turtles. With such a concentration of shark food, it's a perfect place for sand tigers. After mating, they gather here in the hundreds. The females will stay here for several months as their babies develop. Sand tiger sharks have two wombs and over a 12-month gestation period produce hundreds of eggs. Up to six embryos will start to grow in each uterus, where life's already a battle. There are multiple hungry sharks in each womb. They're only food, eggs, and they're siblings. Older babies have an advantage. Their larger size helps them to overpower smaller siblings. Only one shark in each womb will survive. It's a shark-eat-shark world, even before birth. Females keep producing eggs to feed the largest embryo left in each womb. But it's not just the embryo's size that gives it an advantage. It's the most aggressive baby sand tigers that are more likely to be born. That trait is passed down from the males, who initiate mating by biting the female to hold her. It's a violent affair, and the females bear the scars. The most aggressive males mate with the most females, giving their offspring a genetic advantage for success. After a few months, only one dominant baby shark remains in each womb, like this one. Similar to human pregnancies, you can see the baby shark moving inside mom's belly. After 12 months, she'll be born, ready to expand her menu beyond her siblings. On the other side of the world, it's November off the coast of Cape Cod. At this time of year, the Northwest Atlantic seems an unlikely sanctuary for one little-known predator, the porbeagle shark. Despite their impressive strength and speed, porbeagles get much less attention than their cousins, the great white, and the mako. Though pregnant porbeagles are here, they're rarely seen. And scientists are still unraveling their many mysteries. We're out here trying to catch the porbeagle shark, which we also like to call the phantom shark. This is because not a lot of people have heard of or seen the porbeagle. Pretty difficult to catch, and it's usually found in colder waters. PhD student Brooke Anderson is here to study the movements of female porbeagles as part of the research conducted by Dr. James Sulikowski. They believe that the females stay in these cold waters to give birth. The question is, why, when other sharks migrate south by winter? It's windy. It's cold. It's rough out. And this shark is living here in these waters. It's the only shark that stays here year round. One of the unique things about the porbeagle shark is that it's endothermic. And this means that it can actually keep its body temperature warmer than the water temperatures. So we think that they might be using this spot while they're pregnant to reduce their competition and have these unique habitats that they can use that a lot of other species just, they just can't handle. But how do you catch a phantom shark? Basically, then, that shark's coming in. We're going over it, let it swim through it, clip it up on the tail. Yeah, we can leader it. So we need a porbeagle. And when we get one, we're going to satellite tag her. And we're also going to see if she's pregnant. That's one of the most important life history stages you have to study. I mean, they're the moms. They're the ones out there swimming with the next generation. So where they go are areas that we need to know so we can protect them. Because they can thermoregulate, porbeagles are able to use the entire water column in their search for prey, from warmer water near the surface to much colder water at depths of over 4,000 feet. Large eyes help them to hunt in deeper, darker water. But this shark has caught the scent of the bait near the surface. Porbeagle, we can see it right there in the water. The thing just pulled the circle hook. See it circling? We can see the shark right here. Can the scientists catch this massive shark and bring it on board? That's a nice porbeagle right there. Look at that, every hook. All right, this is the key moment right now. We've got to get the shark to the boat. Porbeagles are big. They're powerful sharks. It's going to take everyone on board to land the shark safely. All right, you might be on this one. Here we go. All right, shark's coming on. Two tail ropes. Hold on. Keep going. Big shark. Woo! Bringing 400 pounds of pure muscle on board isn't easy. And the crew need to find innovative and safe ways of holding onto it. You ready? All right, here we go. One of the most important things is to get water in the shark's mouth, which we have, which is great. The scientists must work quickly to keep the shark healthy. So what we're doing now is going to get some measurements. See how big the shark is. Right now, it's a mature animal. This one's a mature male. This is a first. James and his team have never caught a male porbeagle in these waters at this time of year. They believed that males migrated elsewhere after the breeding season. Yeah, I got the cupboard. Why is this shark here now? So we're getting a blood sample. So we'll measure this for reproductive hormones, testosterone for this species, for this male, to see what its levels are. And if it's high, we know that it's just mated. You've got females in this area that are pregnant. So it's an incredible area for this species. It's what they need to survive. The best way to study these elusive sharks is to track them with a satellite tag attached to their dorsal fin. So the tags that we're using transmit a location. Every time this shark comes out of the water, you get a signal of where that shark is in real time. So what's interesting is that the past data that we have for females suggests that they use this place year round. So it's really interesting now to catch a male to see what they're going to do. Do they leave? Do they stay with the females? All really important when you talk about conservation and management and how these animals are using this area. We're going to rotate the shark. Before they return the shark to the water, they have one more measurement to take. Sorry. Using an anal temperature probe. This is a homeothermic shark, right? So it maintains its body temperature warmer than the environment. That's why it can live here, while blue sharks and other species that aren't as good at it leave. All right. You can see that actually the temperature is going up, right? Right now, 74.5 degrees inside this shark. And what we'll do is we'll compare that to what the water temperature is. Right now, I can tell you it's about 20 degrees warmer inside the shark than it is outside. That's absolutely incredible. All right. With measurements complete and the new satellite tag attached, it's time to release this 8-foot-long male back into the sea. 1, 2, 3, push. Here we go. It's angry. Watch the tail. There it goes. Woo! Wow, did you see that swim away? That was amazing. That's incredible. Woo! Good work. Marine biologist. Good job. Hey. Real exciting. Landed a large porbeagle male, which is incredible. This shark was 250 centimeters long. It's one of the biggest I've ever seen, probably 300, 400 pounds. I mean, it was a beast. Most of our work has focused on females, right? It's a really important sex. They're the moms. Where do they go to give birth? But when you catch a male, male's a part of that equation. Where are they mating? Is it here? And if so, when? So that's a really important part of our research. And this is the first male we've ever tagged. So that phantom shark, we finally got the male. So all the pieces are starting to come together, but we still have such a long way to go. Catching a male porbeagle is a rare opportunity to add to the data on this mysterious species. But there is still a major piece missing to the phantom shark puzzle. This ultrasound reveals baby porbeagle sharks in utero for the very first time and only eight inches long. But where are they born? To answer that, the scientists will return next year. The coast of southeastern Australia is home to dozens of shark species. But not all sharks are mega predators. In the nutrient-rich protected waters of Jarvis Bay, many smaller sharks and other creatures thrive, like the Port Jackson shark. It's also a nursery ground for baby Port Jacksons. Port Jackson sharks are found only in the southern half of Australia. The adults migrate once a year from deeper, colder water offshore to this secluded bay to find a mate. It's a congregation of hundreds, maybe thousands. And recent studies reveal something extraordinary. Returning sharks seek out the same individuals year after year, males in one group, females in another, establishing long-term relationships not documented in any other shark. Multiple males vie for the attention of every female. Competition is fierce. Port Jackson mating appears to be a rough affair. Females have developed thicker skin than males to withstand their sharp teeth. Males bite the female's fin, holding her in place while he inserts one of his two claspers. After mating, they go their separate ways. While most sharks give birth to live young, Port Jacksons lay eggs. To give unborn pups the best chance of survival, this mother wriggles the egg free into a deep, rocky crevice where it's protected from predators. Her eggs are a unique cone-shaped spiral nearly five inches in length. Over the next few weeks, she'll lay up to 16 eggs from multiple partners. The corkscrew-like eggs will work their way deeper into the crevice and wedge between the rocks. They'll stay there protected for the next 11 months. This rare footage shows a five-month-old Port Jackson shark inside its egg. Even as an embryo, she must be vigilant. Using electroreceptors, she senses predators close by and freezes, even stopping her gill movements to avoid detection. But not all eggs are so lucky. If an egg rolls into the open, it's fair game. This crested horn shark looks a lot like a Port Jackson. They're close cousins, but there's no familial love here. On his menu is Port Jackson shark egg. Before this crested horn can break through the filament of the egg casing, a male Port Jackson approaches. It seems that help has arrived. Port Jackson sharks are larger than crested horns, and this one has the advantage. The crested horn isn't going to give up his meal that easily. The Port Jackson has to step up. He grabs the egg from the smaller shark. But this was not a rescue mission. The Port Jackson will keep this egg for himself. Just like a chicken egg, the yellow yolk is dense with nutrients to feed the shark embryo. An exposed egg represents a meal for anything that can break through the tough egg case. Nearly 90% of the eggs don't make it to hatching. This baby has survived those odds. Just a couple of days old and seven inches long, she's not much bigger than some mussel shells. She'll have to learn to feed herself quickly. The jaws of an adult Port Jackson are filled with crushing molars and razor sharp teeth. But the baby's teeth and jaws are not fully developed yet. So she sucks in worms and other soft-bodied animals to eat. But she's not the only one out to find a meal. Predators are on the prowl. And baby Port Jackson is on the menu. This fiddler ray is on the hunt. Using electroreceptors in its snout, called ampullae of Lorenzini, the ray scans the seafloor for his next meal, looking for shellfish, crabs, and even small fish like baby Port Jacksons. Just like inside the egg, she freezes in an attempt to hide. But this baby shark has another trick up her sleeve. The coloring of her skin acts as camouflage, mimicking dappled light on the sandy bottom. And by avoiding detection, she gets to live another day. It will be at least 11 years before this baby shark is sexually mature and able to join in the annual Port Jackson breeding season here in Jarvis Bay. It's September, nearly a year since the poor beagle scientists were in the icy waters of the Gulf of Maine. Dr. James Sulikowski and his team are on a mission to catch a baby poor beagle shark. We can put some lines in the water, hopefully catch us a baby poor beagle. All right, let's get those tags on. Let's get the tags on. For the first time ever, the research team is here to catch a baby poor beagle and fit it with a newly developed baby-sized satellite tag. So we know that the baby poor beagle sharks are here in the Gulf of Maine, but we don't exactly know why they're using this habitat. So we've got a rod set at the surface. We've got a rod set at about 50 feet and one set at about 100 feet. We do this because we know, based on our data, that baby poor beagles use the whole water column. So now, no matter what depth that baby poor beagle is swimming at, we have a good chance of catching it. Little baby poor beagles are mischievous. They like to nibble around the bait, and sometimes it's gone. So there you go. It's gone. Little baby poor beagle nibbled around that hook. So we're going to put some more bait on there and give it another try. This phantom shark appears to be living up to its name, but their luck finally seems to change. All right, ladies. Gentlemen, look at this. OK. All right, here we go. Here we go. He's got a good hook. Come on. All right. Look at this beautiful shark. OK. OK, calm down. Baby poor beagles, or as we like to call them, pork chops, are some of the cutest sharks because they really look like miniature versions of the adults. They're small, but they're really chunky. All right, I need somebody on the tail. All right. All right, I got the tail. Get on his head. All right, this is a baby poor beagle. Thank god. We have been searching for this little shark forever. What a beautiful shark. Look at his color. Look at his great big blue eyes. This shark is probably about two months old. Look at this little thing. It's so cute. This is a cute little shark. This is what we're after. Come on, little buddy. At less than three feet from tip to tail, she may be small, but this baby shark is pure muscle and packs a heck of a punch. The team keeps a firm grip on her for safety. And so we're super excited right now. This is the first time that we're putting this tag on this shark. And so this could mean literally everything for the survival of this particular shark, but also for the species. If this is a nursery ground, we have to know this in order to protect these areas. Dr. Sue Lukowski is the first scientist to deploy a baby-sized satellite tag on a baby poor beagle. Tags we've used in the past to track movement were just too big for babies. And so we needed to figure out a way in order to find where babies were going. And so we had to develop new technology. And this new satellite tag is smaller, is lighter, and it actually grows with that shark. So it protects that fin. It doesn't hurt the shark. And we can really get some great movement on baby poor beagles. Baby poor beagles share this area with commercial fishing boats and are sometimes caught by accident. Information on the baby's movements will help the scientists work with the fishing community to avoid catching this vulnerable species. Right here, when that shark surfaces, this will transmit to a location from a satellite that's passing above. So we'll know exactly where that shark is at that time. It's amazing. It's real-time, real-world information. Right now, we're going to release this shark back to the ocean. One, two, three. Watch the line. OK. All right, here we go. We're going to place the shark in. Three. Oh, yeah. Look at it go. This baby shark is safely back in the water. It's only a matter of time before she surfaces again and starts transmitting data back to the scientists. Woo! Oh, my gosh. Yeah, totally insane. It's just so incredible to see it, to see those big eyes, to see that thick tail, that fusiform body, that dark coloration, see it swimming so aggressively away. It's just something that we as scientists, it's like Christmas Day. It's unbelievable for us. Wow, now the fun begins. Now we track this little shark. We see where it goes. We see what habitats it's using. We see how it's interacting with the commercial fishing industry. And we can see how we can get everybody working together to help this little shark survive. Yeah. Let's go fishing. Tagging the baby porbeagle with the newly developed satellite tag is a huge first for science. And before the end of the day, the team get their first ping. Look at that. That's the baby porbeagle we just released. It's already surfacing and transmitting. That's great news. I mean, that means that shark's alive. It's coming to the surface. And hopefully, it will give us a lot of data from here on out. These are the first data points of many as this porbeagle grows in the waters around Cape Cod. There's baby sharks here. If this area is a nursery ground, how are they using it? And how does it connect back to mom? These are all major questions for us. And if they are using this as a nursery ground, then this is a really special place. It'd be the first nursery ground ever for this species, which is incredible to think about. The porbeagle is a shark shrouded in mystery. But with more research being done, scientists hope to have a better understanding of their place in the ocean, starting right here in this potential nursery ground. In Australia, baby sharks are being impacted by a changing ocean. And scientists are on a mission to understand how they can survive. In places like here off Heron Island, on the southern tip of the Great Barrier Reef, a mix of tropical water and cooler water from the south make this one of the most productive places on the reef. And it's home to one of the world's strangest shark species, the epaulette shark. They are also one of the world's smallest sharks, growing to only a few feet in length. And the babies are even tinier, only around six inches long. Like the Port Jackson shark, epaulettes lay eggs. The females hide them under coral heads to keep them safe from predators. After only a few months, the baby epaulette emerges ready for life on the reef. But it's not the size of epaulettes that makes them special. From birth, these sharks have an astounding ability. They can walk. The only family of shark that's able to do this. While sharks have been in the ocean for over 400 million years, epaulettes evolved this behavior only 9 million years ago, making them the most recently evolved sharks in the world. His round, muscular fins act like feet to help him into the tight nooks and crannies of the reef, where he'll find food, hide from predators, and deploy an ingenious strategy. When the tide is high, large, five-foot-long white tip reef sharks dominate the reef. But when the tide is low, the white tip is too big to maneuver here. It's a situation that epaulettes use to their advantage. The fierce tides on Heron Island pull water off the reef at an alarming rate, leaving a shallow landscape of trapped water. Most fish move to deeper water off the reef as the tide goes out or risk being stranded. The epaulette exploits this extreme tidal change to hunt when the competition is locked out. But as the tide continues to recede, the epaulette faces a challenge. These isolated tide pools are low in oxygen, making it difficult for most fish to breathe. But the epaulette has another unique ability. He can survive out of water. He slows his breathing and heart rate and shuts off parts of his brain. Now he can live for up to an hour without any oxygen before reconnecting with the sea. Epaulettes are the only shark that can do this. It's an adaptation that has helped them thrive in places like this, where the reef experiences dramatic changes in short periods of time. While epaulette sharks have mastered the ability to cope with extreme changes in oxygen levels, how they react to extremes in temperature is unknown. I see a tail. Where? Oh, yeah, right here. They're so camouflaged. Holy cow. Oh, nice. So camouflaged. All right, let's get this one. Yeah. Got him. In we go. Come on, little one. Nice work. PhD student Carolyn Wheeler and Dr. Jody Rummer from James Cook University are here to study the temperature tolerance of epaulette sharks and what it could mean for their future in a warming climate. When the low tides coincide with the afternoon times like that, it gets really warm on the reef flat. There's not a lot of water, and it heats up really quickly. So the sharks have to be really tough to be able to handle these kind of short temperature windows in the afternoon on the reef flat here. The scientists catch a number of sharks of different ages, which they can tell by their size and weight. Then they measure the water temperature where they find the sharks. Water that's too warm will stress the sharks. There are two life history stages that are particularly vulnerable. The first is early life history, so when the sharks are developing in their egg case, so when they're embryos, and soon after a hatching. And the second vulnerable life stage is reproducing adults. They're putting a lot of energy into creating the precursors of eggs. And so this also is a very vulnerable stage. Unlike baby Port Jackson sharks, which take 11 months to incubate in their corkscrew eggs, baby epaulettes spend only four months growing inside their eggs before they hatch. Just four months from a tiny wriggling worm-like creature to this mini shark. It's one of the shortest incubation periods of any shark species. But as water temperatures rise, babies that are heat stressed consume their yolk sacs more quickly. And they hatch almost a month earlier than average. When the baby sharks are born earlier, they're weaker than normal and unable to perform normal functions as well, such as learning to walk and hunting for food. And the temperature is quite high. Yeah, what is the temperature? It's 26.6 degrees Celsius, which is about 78 degrees Fahrenheit. Reef flats like this one can vary drastically with each changing tide. A low tide in the middle of the day can be up to 50 degrees Fahrenheit A low tide hotter than a high tide in the early morning or at night. It takes a lot of energy to grow from a tiny embryo into a baby shark. So any additional stress can be a big problem. We're really trying to understand how challenging environmental conditions are costing epaulette sharks more energy to live. So we are using this species, the epaulette shark, as an indicator species. Because they're so tough, if we find thresholds or trigger points that are challenging for them, that is a very good early warning system for us for the health of the reef, not just the Great Barrier Reef, but reefs in general around the world. In a changing climate, sharks are still key to the health of the ocean, beginning with baby sharks.