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It's the birthplace of life on our planet. The source of more than half of the Earth's oxygen. Yet uninhabitable for 80% of the world's species. Millions of years of evolution have left only the strongest and strangest to survive in this wondrous but challenging environment. And it's not all down to size. Microscopic life forms live alongside the mighty, the menacing, and even the mysterious. An eclectic community of creatures all learning how to endure in this sometimes hostile home. From the lovers to the fighters, the devious to the delightful.
This is life under the sea. More than 200,000 different species share the ocean. All united by their constant need to feed. In this fish eat fish world, danger lurks on every current. Calculating killers, ambush attackers, and opportunistic hunters all fixated on finding their next meal. It's survival of the fittest, the fastest, and the fiercest as the oceans' top predators go on the attack. When it comes to hunting, bigger is generally better. But for those marine animals don't have size on their side, it helps to be devious, dazzling, and nonetheless deadly.
This bizarre-looking creature is only as big as a human hand, but it's the world's most efficient killer. Long before dinosaurs existed, the peacock mantis shrimp was terrorizing some of the ocean's smallest inhabitants. the fastest in the animal kingdom. At roughly the speed of a.22 caliber bullet, and 50 times quicker than a human blink, it extends its front clubs to shatter the exoskeletons of its prey. If it misses, no matter. The punch [snorts] is also fast enough to boil the water around its target, leaving it stunned.
The heated water bubbles can reach temperatures close to the surface of the sun. It's a classic case of overkill. The impact from the shrimp's clubs alone can splinter bone and shatter glass. Such a powerful punch requires a degree of self-preservation. Layers of elastic fibers under their front limbs act as shock absorbers, cushioning the blows. Scientists believe this little club may hold the clue to building super strong body armor for soldiers. Nature, as usual, is a few steps ahead. With their speed and size, the ocean's apex predators have a fearsome reputation.
But on the ocean floor, killer tactics can be equally effective and far more surprising. The wobbegong does not share the athletic gifts of other sharks. Where most predatory animals rely on force and agility, the wobbegong uses deception and trickery. The key to a good ambush is all in the disguise. Sitting on the seabed, it blends and hides. Often poking just its wide tasseled mouth out of little caves or from under ledges, waiting for prey to swim close. With a vicious suck, it's all over in a heartbeat. This lazy cave dweller also lures prey in by mimicking other sea creatures with rhythmic flicks of its tail. Today, it's caught the attention of a passing fish.
Unfortunately for this victim, curiosity can kill. The wait-and-watch method works well for many of the ocean's bottom feeders, including this fragile-looking fish. Don't be fooled by its delicate appearance. This leaf scorpion fish is an accomplished killer. It's a poor swimmer, spending most of its time resting on something solid. Its thin body mimics the motion of foliage floating in the sea, lulling little fish into a false sense of security. If they stray within striking distance, the oversized mouth acts like a vacuum, the victim disappearing without a trace.
No matter the meal portion, there's always room for a little extra. Other members of the scorpion fish family take a more active approach to their eating. Using its elaborate headdress and skirt, the lionfish relentlessly stalks its prey. Fish, shrimp, and crabs are all rounded up with remarkable skill. The glamorous pectoral fins are used to herd its victims into corners, where they're easy pickings. A specialized swim bladder allows the lionfish to alter its center of gravity while preparing to attack.
Helping position itself for a precise strike. And if that fails, it has another sneaky tactic. Blowing water towards the herded prey. These jets confuse the hunted and help to reorientate the small fish so they're head-on to the predator. The stonefish has no interest in playing with its food. This cold, calculating killer is completely fixated on capturing its next meal. The body of this scorpionfish has evolved for effective concealment.
Its venomous spines are just a defense mechanism reserved for only the greatest of threats. Digging down into the sand, the stonefish is poised for attack. Waiting for the perfect moment to lash out. But astonishingly, not the scariest assault to come out of the seabed. The bobbit worm is the stuff of nightmares. Buried deep in the sand and muck, this carnivore can grow up to 3 m long. Not that passing prey would even know it's there.
Only its antenna and outstretched jaws protrude from the silt, detecting movement and tasting for scent. When it senses something is close, it thrusts upward with alarming speed, clamping scissor-like jaws around its unlucky victim, dragging it into its lair. Even a poisonous puffer fish is no match. A brutal ending dealt by a blind, brainless creature. Intelligence does count for something in undersea attacks. The cuttlefish has one of the largest brain-to-body ratios of any invertebrate, which it uses to play mind games with its prey. With the target in sight, a flamboyant cuttle manipulates pigment cells below its skin, creating a psychedelic show
that's designed to confuse and even hypnotize its victim. The beauty of the display is matched only by the chilling speed of the snatch. As well as eight arms, every species of cuttlefish has two extendable feeding tentacles that launch out as a single spear. When snacks are suckered, they're drawn into the razor-sharp beak hidden within the cuttlefish's colorful mouth. It's all over before the prey knows what's hit it. Dazzling and deadly accurate, a winning combination on the reef. It's not the only member of the cephalopod clan to capture more than just its fair share of attention.
It's only pint-sized, but the blue-ringed octopus stands out. Its patterned skin is a sign of the toxin within. This curious cephalopod carries venom 1,000 times more powerful than cyanide, making it one of the ocean's most dangerous animals. This skilled assassin uses stealth to approach its victims. Its fast, flexible body pounces, trapping the crab. But the struggle isn't over. The octopus needs to draw the crustacean into its centralized beak to deliver the paralyzing proteins. Pulsating patterns signal the cephalopod's heightened state, brought on by the thrill of the kill. But its grip is firm. Resistance is futile.
And there's no need to rush. Once its target is immobilized, the blue-ringed octopus can take its time to devour its meal. A slow and steady approach also works for a different deadly hunter. The geographic cone snail is the most venomous of its 500 family members. It doesn't even need to touch its prey to paralyze it. While many of its relatives target other snails and crabs, this slow-moving gastropod has upped the ante, choosing fish instead.
They hunt by smell, using their oral siphon to sniff out a victim. To increase their odds of success, the cone snail releases a form of insulin into the water to stun its prey. It enters the gills of the fish, sending it into hypoglycemic shock. Unable to escape, it's slowly engulfed by the predator's large, expanding mouth. But, this isn't the only chemical weapon the cone snail possesses. Below the siphon, another appendage called a proboscis houses a venomous tooth. When a sleeping victim is found, a harpoon is fired to inject toxin.
The fish struggles for only a few moments before succumbing to the sedative, allowing the snail to swallow it whole. Another of the ocean's most lethal creatures also uses venom to hunt. Wherever it travels, the box jellyfish trails a deadly weapon. Its 60 tentacles can stretch out to 3 m and each is lined with up to 5,000 stinging cells. All designed to rapidly kill or stun anything they come into contact with. The instant paralysis helps avoid a damaging tangle with a wriggling victim.
Protecting the box jelly's delicate body as it draws the catch up into its head. Unlike most of its relatives, this venomous jelly doesn't just go with the flow. Instead of waiting for fish and crustaceans to drift into its tentacles, it actively hunts. Swimming at speeds of up to 7 km an hour. Sea turtles are one of the few predators that can stop jellies dead in their tracks. And it's not a quick kill. They slowly bite away at the bell.
Thick skin on the reptile's head protects them as they eat their way towards the stinging cells. The turtle's throat is lined with spine-like protrusions which act as a barrier while swallowing the tentacles. A fluid-filled food that won't leave a lasting impression. Some of the seas most calculating killers look more like clowns. The colorful coat of a nudibranch gives no hint of the devious creature within. [bell] There are over 3,000 species of these miniature mollusks. Their vibrant patterns are drawn from the food they eat.
Coral sponges and anemones are all targeted. And if their prey has just eaten, all the better. This sea slug pirate is a prolific plunderer. A coral polyp that has just gorged on zooplankton is twice the meal. The nudibranch will also eat its own kind if the opportunity presents itself. Further proof the oceans devious and deadly will stop at nothing if they're hungry. There's a rule of thumb in the marine food chain. Larger animals target smaller prey. But there are a few exceptions.
Coral polyps are minuscule invertebrates. When thousands of them forge a bond, they create a structure that's simply stunning. Each tiny sack-like animal is only a few millimeters wide. Over the years, they construct an outer skeleton which becomes their home. To sustain their building efforts, they need constant food. When the sun goes down, tiny stinging tentacles emerge from the rock-like formations. Each animal's single opening is designed to catch zooplankton and other microscopic prey. But sometimes, they bite off more than they can chew.
A baby squid has drifted within reach. Too much food for just one polyp. But the inhabitants of these coral colonies are community-minded, sharing one interconnected stomach. Whatever the individual catches benefits all. And with a growing reef to sustain, the demand is never-ending. The strict pecking order of ocean feeders has shrimps right near the bottom, scavenging whatever leftovers they can find on the seabed. But not the harlequin. It feeds almost exclusively on starfish, up to 100 times its size. Using antennae, these plucky eaters sniff out a meal.
The key tactic to taking on a much larger target is to disable it. For a sea star, this requires flipping it over. Hundreds of tiny tubular feet help it hold firmly onto rocks. But the shrimp's sharp pincers slice through these sticky attachments. Once it's turned over, the sea star's soft belly is exposed and eaten. The victim is consumed alive. The feast can last over weeks or even months. Even more ghoulish, there's evidence the shrimp might exploit the sea star's extraordinary ability to regrow severed limbs.
Feeding their dying prey to make the meal last longer. One of the sea's most destructive hunters doesn't mind taking on a big challenge. The crown-of-thorns starfish is the prime pillager of the reef. This prickly character has an insatiable appetite for coral polyps. Each animal can decimate 10 square meters of reef a year. Far in excess of how fast its victim grows. And leaving a coral graveyard in its wake.
Human attempts to control the problem have only made matters worse. Thanks to the sea star's regenerative prowess, a cut up crown of thorns can grow into many more. A prolific enemy sometimes requires a mighty challenger. The triton snail is one of the main predators of the crown of thorns. It's the ocean's largest snail, growing up to half a meter in length. Just a whiff of an advancing mollusk is enough to make the starfish flee. But this is one time the snail will win the race.
Snatching the prey with its large muscular foot, it tears through flesh and administers a paralyzing saliva, then feeds slowly. A giant triton might only eat one crown of thorns per week, but its presence is enough to scare others off, making it difficult for the destructive starfish to spawn. A good deed done while on the hunt. Coral reefs may appear expansive, but they're divided into personal territories. The smallest inhabitants will aggressively guard their patch and the food within it, even if the invader appears larger than life.
The herbivorous damselfish is a passionate reef farmer. They tend to their tasty algal yards with a fierce persistence. An octopus that's begun an advance doesn't know what's coming. The feisty damselfish relentlessly attack the intruder. When multiple approaches aren't enough to deter the octopus, the fish follow up with a bite. For the cephalopod, the chance of a meal is not worth the hassle. Wisely abandoning the hunt in favor of finding food elsewhere. While some chase away predators, others are attracted to them. With its jagged gaping jaws and keen sense of smell, the moray is a formidable foe. At just 6 cm in length, the delicate cleaner
shrimp is no match for this 30 kg eel. And in fact, it should be part of its prey. But this clever crustacean has done a deal with this devil of the deep. In return for keeping the eel healthy, the cleaner shrimp won't be consumed. It crawls along the moray's body feeding on parasites, dead skin, and leftovers. Nowhere is off limits, taking particular care to avoid the razor-sharp teeth. This symbiotic relationship benefits both, leaving the eel free of disease while providing a body of food for the shrimp.
Sometimes taking on a giant can have a fairy tale ending. When morays are on the move, they need more than a cleaner to help. Their poor eyesight can be a hindrance when hunting, and relying on smell has its drawbacks when there are many escape routes on the reef. Enter the leather bass, a fast reactive fish that can stop fleeing prey, but can't squeeze into tight spaces. When their talents are combined, this odd duo is an unbeatable force.
The moray's flexible body can weave in and out of tight crevices, flushing out fish. For the scared prey, the options aren't great. Into the jaws of the moray down below, or be caught by the leather bass hovering above. Chances are both hunters will end up with a meal. But not all partnerships are as equitable. At first glance, the slender tube-like body and long snout of the trumpet fish look unintimidating. But this comical carnivore is a clever ambush hunter. It suspends itself vertically and lunges down on prey from above. There are occasions, however, when a little concealment helps them get closer to the action. In an act known as shadow hunting, the trumpetfish hitches a ride with a larger
herbivorous species like the coral trout and uses it for cover. Other reef animals don't fear the plant-eating trout, which helps the hidden trumpetfish get within striking distance. It's a sneaky tactic and a complete drag for the hapless host. Some sea creatures are completely reliant on others to find their food. The remora has codependency written in its genes. They've evolved a suction disc on the top of their heads to attach to larger animals.
Traveling vast stretches of the ocean hidden from other predators, they feast on scraps from their host. But these stowaways aren't without their benefits. The remoras will also eat the irritating parasites found on the larger animal's skin. Some will even consume their host's excrement. Processed food is better than none. In the ocean, odd pairings can be surprisingly efficient. For most marine animals, self-sufficiency is the key to becoming well-fed, evolving tools to help them hunt in their own right.
Meal times are all-encompassing for the reef octopus. This cunning cephalopod goes net fishing with its own body. On each of its eight legs, there are two rows of powerful suckers and a loose webbing. Using these thin layers of skin, it can balloon its body over rocky coral heads, trapping any unsuspecting fish inside. Once caught, the victim is secured by some of the suckers and drawn into the beak of the octopus. An effective way of finding food by casting the net wide. But it's not the only fisher in the sea.
Meet the frogfish. A family of expert anglers well-equipped to catch a meal. As ambush hunters, they don't like to give away their location, relying on camouflage to conceal themselves amongst the coral and rocks. These awkward slow movers don't have a swim bladder, instead shuffling around on four arm-like fins. Which should be a problem when they target fast-moving fish. But this colorful angler is quick where it counts. Its mouth extends up to 12 times its normal size, capturing ignorant prey in a fraction of a second. And it's not the only tool to help it hunt.
Frogfish can catch a meal with a line and lure. A rod-like appendage known as an illicium is extended out in front of its face. The bait is called an esca, a tiny growth which mimics the movements of a tasty worm. Even when a fish does take the bait, the angler isn't always successful reeling it in. Some days, it's the tale of the one that got away. Other clumsy swimmers have developed different ways to compensate. With a small fin-to-body ratio, the pufferfish is going nowhere fast. But other aspects of its anatomy help it to hunt.
Over millions of years, their four teeth have fused together to form a powerful beak that can crack open crab shells, clams, and other shellfish. And there's no danger of them going blunt. The teeth never stop growing, so pufferfish need to use them on hard surfaces just to keep them trimmed. For a fish that can soar through the ocean, the eagle ray is very grounded with its choice of meal. This foraging predator has developed a rather unique way to unearth worms, mollusks, and crustaceans buried beneath the sand.
They have a shovel for a snout and a nose with special electrosensory pores to detect hidden prey. When they get the urge to investigate, they extend their lower jaw to sift through the sand and silt. The unlucky prey is uprooted from its hiding hole and crushed in the ray's strong dental plates. It's another type of teeth fusing that's developed to make short work of the many hard bodies near the bottom of the ocean's food chain. Some superpowers are carefully concealed. Hidden in an otherwise unremarkable resident of the reef. An ordinary looking fish of ordinary size.
Swimming in an ordinary way. But, with a jaw-dropping skill. The slingjaw wrasse can extend the bottom of its mouth to more than half the length of its body, the most of any fish. The free-floating lower jaw shoots out in 1/30 of a second. This super quick action turns the mouth into a straw. Enabling it to reach in and suck out prey from coral crevices. It's all over in an instant. Allowing the slingjaw to return to its deceptively non-threatening fishy front.
Other animals have more subtle ways of securing a meal. The titan triggerfish is one of the more solid species on reef. It can weigh up to 13 kg and it puts that body mass to work to find food. Strong teeth are used to shift rocks and coral chunks to reach mollusks or crustaceans. And it's well designed to tackle spiky sea urchins. The titan's leathery skin is thicker than on most other fish. Its eyes are set far back from its mouth and its fins are closer to the rear of its body, keeping everything delicate clear of danger.
But this trigger fish has another technique for attacking prey. It spits at it. By blasting water jets down onto the seafloor, it hopes to unearth a treat. Finding a clam is one thing. Opening it is another. When its teeth can't crack the shell, it tries dropping it instead. But today, the soft sand isn't helping. For once, the mollusk has defeated the power of the titan. Sometimes it takes more than tricks and tools to triumph in finding food. Most sea creatures are used to hunting alone. But a few species have learned to work collectively for the greater good. As adults, striped eel catfish are
highly venomous with spines on their fins to ward off predators. As juveniles, their toxins haven't fully developed, leaving them more vulnerable. For safety, they stick together forming dense schools of hundreds of fish moving in formation. Sensory whiskers known as barbells sweep across the ocean floor searching for tiny crustaceans and algae. In an undulating wave, the back row will leapfrog the front for efficient and effective grazing for the entire school. Synchronized feeding that ensures no one misses out. Not all marine animals eat constantly. Some can go days or even weeks between meals. But when they do finally feed, they've worked themselves into a frenzy.
A pack of white-tip reef sharks is preparing for a hunt. Dozens have gathered to launch an assault-style attack on the reef's nocturnal sleepers. Many of these fish are hiding out of sight, but they're not out of mind for these white-tips. Like all sharks, they have electroreceptors that detect faint movement as signals. Even the quickened heartbeat of a stressed fish is enough to launch the pack into action. The white-tips ram their life bodies into cracks and crevices.
Working as a team, some block exits while others wriggle through tiny ravines chasing their prey out and into the open mouths of the pack. With all the chaos, some residents can slip through virtually unscathed. But for others, the furious bombardment proves too much. Targeted attacks are not confined to the reef. Pelagic fish are those that live and feed in the open ocean. Only the most formidable hunters can survive in this sparse, desert-like environment. The sailfish is a samurai of the sea.
A heavily armed warrior capable of growing up to 3 m and weighing over 100 kg. Its sword-like bill and oversized dorsal fin are designed for maximum speed. It's been recorded swimming at 110 km an hour, making this the fastest fish in the sea. And a master collaborator. Working together, they heard a school of sardines towards the surface and into a bait ball. Taking turns to attack from different sides to confuse their prey. These swiping bill attacks only result in a kill a quarter of the time, but they cause injury to many in the process.
Battered and bruised, the sardines grow weary, making it easier for everyone to get their fuel. No matter how fast or effective their weapons, the sailfish know that in the open ocean, they'll catch more together than if they go it alone. It's a concept also adopted by many marine mammals. Dolphins have a reputation for being playful. But, when it's time to hunt, they're one of the ocean's top predators. These intelligent, powerful animals must eat around 6% of their body weight each day. Fortunately, they've developed a highly refined tracking system for finding food.
Dolphins use echolocation. They send out a series of clicks that bounce off any objects close by. As the sound waves return to the mammal, they receive an accurate picture of the size and distance of the potential prey. Working together, they can round up their meal. But, these clever creatures have evolved an even more extraordinary technique, putting their lives in danger in the process. Shore hunting is a high-risk, high-yield way of feeding. The pod chases fish onto sandbanks where there's no chance of escape.
The only problem is dolphins can also become stranded. It's all a matter of timing and judgement. Far enough out to block all exits for their prey, but with enough water around them so their muscular bodies and powerful tails can return them to the sea. Other cetaceans have taken a gentler approach to collective feeding. It takes a lot to fuel an animal that can weigh more than a semi-trailer. But rather than targeting big prey, these whales are filter feeders, using their baleen plates to sieve out tiny crustaceans. And they need to consume a staggering amount of them daily. During the summer months in the polar regions, they gorge on thousands of kilograms of krill each day, building up enough energy for their annual migration to warmer waters to
breathe. To maximize efficiency, these mammals join forces and engage in bubble net feeding. They position themselves around the krill, exhaling air from their blowhole to encircle them. The curtain of bubbles forces the planktonic prey together and concentrates the meal. Humpbacks then lunge upwards with mouths open wide, taking in enormous volumes of water with one giant gulp, keeping the krill, and draining the excess out. It's an unorthodox method of getting a meal, but sometimes it takes a communal effort to feed the masses. Another, much smaller mammal is a deceptively powerful predator.
Resting on the ice sheet, this leopard seal's soft, blubbery body doesn't appear threatening. But it's one of Antarctica's greatest hunters. In the coldest place on Earth, this warm-blooded killer is built to attack. Powerful jaws and long teeth, combined with large flippers, help it to snatch unsuspecting prey. Leopard seals will eat penguins, fish, squid, and even smaller seals. Most of their hunting takes place in the water, waiting for land animals to enter, playing with their prey like a toy before finishing them off. But leopard seals are not Antarctica's apex predator. That title is taken by the orca.
Also known as a killer whale. It's the largest member of the family, growing to 10 m long. Its diet includes fish, seabirds, leopard seals, and even sharks. These are calculating killers, using echolocation to hunt prey, and working collectively to herd them. Like smaller members of the dolphin family, they've learned the dangerous trick of half-beaching themselves to grab a meal. Their targets are seemingly unaware of the danger. Time and time again, the orcas launch their attacks on the shore. The first seal pups narrowly escaping.
Persistence pays off for the killer whale. Experience ultimately triumphing over the exuberance of youth. There's one group of animals that has ruled the oceans virtually unchallenged for more than 450 million years. There are estimated to be around 500 species of sharks, but only 30 of those are considered apex predators. The tiger shark is amongst them, an indiscriminate killer. If it moves, it's a target. They're the second largest of the hunting sharks, weighing up to a ton. As adults, they have no known predators, although they have been observed eating their own young.
The tiger's powerful, striped body is aided by excellent eyesight. One of the few animals capable of crunching through a turtle shell. It's no coincidence these sharks turn up when the defenseless reptiles gather to mate, timing their arrival to take advantage of an easy meal. But there is one undisputed king of the ocean attack, the great white shark. A natural-born killer, equipped like no other to take down its prey. Every aspect of its anatomy is designed to give it the edge.
A skeleton made of lightweight cartilage, a unique circulatory system keeping its body temperature higher than the surrounding water. Both combining to give it speed in pursuit. But most of its predatory prowess is due to its jaws. A bite force of almost two tons. One of the most powerful on the planet. A mouth filled with 300 razor sharp teeth designed to grip and rip at flesh. When a tooth falls out, another replaces it. Up to 20,000 in a lifetime.
This terrifying weapon is powered by two tons of muscle shaped like a torpedo firing at an explosive 50 kilometers an hour. The great white stalks prey from below launching vertical attacks. Clearing heights up to 3 meters above the surface. Such an extreme expenditure of energy requires a high fat diet. Sea lions and seal pups are their preferred food. One every three days is enough to sustain the shark. By combining size, speed, and strength the great white has become the ultimate killing machine. As the oceans animals fight it out for
their place in the food chain. The clever and the cunning have staked their claim alongside the big and the bold. With only 5% of the ocean explored, many more predators could be out there on the attack under the sea.
