this is Earth 4.4 billion years ago a toxic sterile ball of scorching Rubble meteorites rain down on its surface clouds of lethal acid smother it the Earth seemed destined to remain devoid of life but that was about to [Music] change another planet Thea smashed into Earth and the two planets fused creating a brand new world our world even today Thea lies right beneath our feet a smaller chunk of Thea became our moon and slowly our oceans formed until life on Earth was ready to begin but who would inherit this blue planet this ser Aries tells the extraordinary story of life before the dinosaurs a time when strange and Savage creatures fought a ruthless battle to rule the Earth amongst them were our own earliest ancestors whose survival would decide whether we humans would exist at all as they evolved these bizarre creatures created the blueprint not only for our bodies but for everything living [Music] today this is life's forgotten story an epic war for our world a war between monsters [Applause] [Music] this is our planet 530 million years ago nothing yet lives on land but in the ocean it's a different [Music] story life has already been evolving for millions of years at a slur and steady Pace the seas are full of simple soft-bodied creatures blindly drifting in the [Music] currents now however in the coastal shallows below Evolution has stepped on the [Music] accelerator Predators have taken their first bite this is a nomal carus Earth's first super Predator this 2 m long monster owes his success to a Monumental evolutionary Landmark eyes they may look bizarre but they're not unique many predators in the Cambrian Seas have also evolved eyes and so have their prey the consequences have been explosive being able to see and react to enemies has triggered an arms race between Hunter and Hunted this battle continues today and is a major force behind the variety of life to combat being visible and vulnerable 80% of creatures in these shallow Seas have sturdy skeletons on the outside of their bodies these armored animals are called arthropods in the future they'll give rise to insects and spiders but in these crowded Waters there's competition everywhere and even the mighty anomala car's defenses are constantly put to the test [Music] for [Music] [Music] rigid armor splits if bent too far leaving the loser vulnerable to a completely different threat [Music] [Music] this is haiku Ikes he's the size of your thumbnail but he's an evolutionary giant he's the first ever fish our earliest known ancestor he's unique cuz instead of having armor on the outside he's tough inside he's evolved A Primitive backbone he's the very first vertebrate Forerunner of all future backboned animals from the dinosaur to the elephant to us his flexible backbone makes him more maneuverable than spineless anomalacaris he can scaven flesh then Dart away [Music] unharmed our tiny backboned ancestors have survived a Sea of Monsters but there are still many more battles ahead they must adapt or die evolution takes over as millions of years pass fish build on their basic design the muscles around their backbone evolve into a powerful tail and fins appear they evolve a distinct head he may not look like you or I but this odd fish is becoming the blueprint for our own [Music] bodies this is kefal aspis she's a peaceful Grazer who sucks up algae through her jawless mouth but she's also developed a tough protective head and thick scales our ancestors arthropod enemies have also been evolving and they're ready for round two 100 million years have past and the fight for survival has filled the syuan Seas with variety some creatures here would be recognizable today sponges filter food alongside sea [Music] urchins the orthone is a distant relative of squid and cuttlefish but he's as long as a truck this world is terrorized by a new improved generation of armored arthropods meet Bronto Scorpio His Kind may look like modern scorpions but they're a meter long and have gills the arthropods have upped their game these monsters have a superior Armory to anomalacaris a stinger the size of a light bulb scorpions are the top predators in the syuan seas and prey is plentiful in their seabed hunting [Applause] [Music] [Applause] ground Bron Scorpio zeros in on his next meal [Music] but keil aspis has evolved an early warning system special sensors on her skin detect the tiniest vibrations in the water we've inherited similar sensors they make us sensitive to touch [Music] with her defensive headgear keil aspis can't swim fast for long she must rest frequently soon she'll tire completely [Music] keal aspis suddenly changes her path she's picking up bad vibrations something Bronto Scorpio can't detect [Music] [Applause] [Music] ter goas is the Titan of sea scorpions the biggest arthropod of all time more than 3 m long she's the size of a crocodile she's turned the tables on Bronto Scorpio he'll make a good meal for her young in such dangerous Seas there's nowhere to hide when breeding season comes the keal aspis congregate to head for the one place they might escape the Scorpion's grasp fresh water in land land at this time is like an alien planet it's a Barren expanse of roasting Rock hotter than the Sahara the air would be toxic to us it has much less oxygen and 300 times more carbon dioxide side than today but some forms of life have gained a foothold in this furnace the first pioneering plants konia has a unique survival strategy it's the first plant to send shots upwards trapping extra light to help it grow this basic design will eventually lead to our tallest forests [Music] the keilas spus Convoy plows up River away from the sea they're making the marathon Journey Back to the spawning grounds where they hatched incredibly our fish ancestors already use memory they use familiar landmarks to navigate their toughened heads protect a vital weapon one of the first complex Brains it's much more developed than their scorpion Rivals who have no memory at all it's thanks to these primitive fish that we can think and solve problems today but the fish have underestimated their enemy it is the arthropods and not our ancestors who have taken the first momentous steps out of the sea onto dry land Bronto Scorpio has a huge [Applause] Advantage as well as gills he has simple lungs made up of hundreds of thin layers of tissue he can't breathe in and out like we do he just absorbs the oxygen into his blood equipped to maximize the little oxygen available and with their armor to protect them from the Sun the Scorpions Patrol the shoreline Scavenging on whatever the sea washes up next [Music] finally the fish approached their destination they've navigated their way back to the spawning pool where their lives began weak from their long journey now they have to cross a ridge of rock to make it from the river to the pool [Music] the first fish make it through and start to lay their eggs but the exhausted Capal aspis have company [Music] [Music] passing scorpions have stumbled on this [Music] bounty but the fish have numbers on their side the clever keesus have navigated their way while Bronto Scorpio are only here by luck they're soon stuffed to the gills while the fish keep [Music] jumping one scorpion is still hungry but he can't feed he's become a prisoner in his own skin his rigid skeleton is now a handicap it can't grow with his body he needs to shed his hard skin and then grow another expanding while the new one is still soft for such a large creature this is a long process [Music] [Applause] [Music] next morning there's no sign of life in the spawning pool the Scorpion has missed his [Music] chance our ancestors have survived they've laid their eggs and are returning to the Sea brain has triumphed over Brawn and soon they won't be such soft targets Evolution starts to give them weapons to fight back over millions of years the fish's gills adapt to form the first jaw with the very first teeth now they're equipped to go on the attack some develop tougher bones and muscles in their fins and shoulders which become the first limbs this is where our arms and legs began with this four limed design our ancestors finally haul themselves out of water onto land [Music] this is the giant amphibian hpan the Prototype land dweller for the next 300 million years [Applause] hpan are over a meter and a half in length much larger than most amphibians today they've carved out a home along the water's [Applause] edge some of their arthropod enemies have now become land Specialists but the air here isn't as oxygen rich as water the arthropods primitive lungs can only absorb enough oxygen to fuel smaller bodies to adapt they've had to reduce their size and now their role has been reversed they've helped feed the growth of our amphibian ancestors still life for this Pioneer is far from [Music] easy it's a whole new world in the last 50 million years plants have developed into trees and with nothing around to eat them they've grown into vast forests pumping oxygen into the air [Music] [Applause] hittin has evolved complex lungs to exploit this new oxygen his lungs are Sachs just like ours and he breathes like we do forcing air in and out so his blood can absorb more oxygen we still rely on the design developed in this strange amphibian hitan can breathe on land but he's still water bured his skin is much thinner than ours and it dries out in minutes so he has to keep it [Applause] wet and water is a danger zone [Music] the fish are now our ancestors enemies primitive sharks are constantly on the hunt but even sharks are small fry in comparison to some flesh eating [Music] fish hinero weighs 2 tons and is 5 m long she's an insatiable carnivore [Music] the amphibian limbs are his Saving Grace for now as the burning Sun dips hpan can spend more time on land [Applause] this stretch of Shoreline is his territory and his trump card with the opposite [Music] sex hit and females are choosy and will only go for males who can defend their tur they also only mate during a short season [Music] the male's future depends on passing on his genes and tonight could be his last [Music] chance as night arrives so does the [Music] competition another male with his eye on this Prime patch [Music] to avoid injury the males demonstrate their strength in a strange push-up contest [Music] this rival is not up to the challenge but now our male may be too late for love Dawn and all the females in the area have M and moved on hpan seems to have missed his chance the only attention he's attracting comes from the dark Waters of the lake a female finally answers his call and the male sees is the [Music] [Music] [Applause] opportunity amphibian eggs are soft and they Young have gills not lungs so they must be laid in water where amphibians are most vulnerable [Music] hinia can attack like a killer whale after a seal only just missing her prey but she has remarkably powerful fins [Music] and takes the male by [Music] surprise the end for this hpan but the amphibians are about to find a way to leave the dangers of the water behind for good [Music] the key to their future success lies in changing their eggs they evolve a hard waterproof casing which protects the young inside from the drying Sun so they can be laid on land the babies will hatch out fully developed air breathing and independent they are the first ever true vertebrate land lovers the very first reptiles but as they move in land they'll face an ancient enemy more deadly than ever before the arthropods are back [Music] 300 million years ago much of the Earth was covered in vast swamp forests here nothing is as it seems the 50 m Giants towering above this water world may look like trees but they're actually distant relatives of [Music] ferns even the air is alien over a third is oxygen much higher than at any other time in history this oxygen rich atmosphere has fueled the growth of new super sized arthropod Predators this Misa spider is the size of a human head she'd be hunting cats if she were alive today she's an ambush Predator operating from her underground headquarters safe in her burrow she rests her feet on carefully constructed trip lines these allow her to pick up vibrations from the outside world reptile petacas us is hunting on the forest floor unlike our amphibian ancestors he has tough scaly skin which traps moisture inside his body vital for all land dwellers because he doesn't dry out in the sun he can Venture away from water but that means encountering new predators [Music] the reptile outruns the spider he's evolved a complex heart much more efficient than his enemies in fact the template for our our own it's a powerful pump that pushes blood and oxygen around his body to his muscles so he can run at high speed without stopping for a rest this time though he's trapped inside a [Music] log at first the spiders armor stops her squeezing in but she's not going to give up so [Music] [Music] easily back in her Lair Misa will inject her victim with digestive juices to dissolve him from inside not only the arthropods have flourished in the swamps the Carboniferous is one of Earth's greenest [Music] times it's this very abundance of plants which has pumped up the Air's oxygen to extremes fueling the arthropods growth spurt [Music] The swamp's Damp conditions are perfect for plant growth but the water levels are unpredictable they've [Music] risen the spider drags her dinner home but something's wrong [Music] her headquarters are flooding she'll have to evacuate she can't dig so she'll have to find another hole she can adapt and once outside she's vulnerable to larger Predators meura is a monster dragonfly Queen of the Carboniferous Skies with a wingspan of almost a meter she's the size of an eagle with an appetite to match high above her carbonifera kingdom normally she's Invincible but trouble's Brewing the flood below is due to an approaching storm the super oxygenated atmosphere which has helped helped fuel the growth of the insects and arthropods is highly volatile a lightning strike could trigger an explosion the clock is ticking for the swamp the rising water levels suit one group of hunters amphibians they've continued thriving over the last 60 million years their thin skin still restrict them to the waters Ed Edge but they're now powerful Predators with a devastating pair of Jaws ready to Ambush anything that wanders within [Music] reach the homeless spider tries her luck further Inland but other Misa fill the forest floor and they don't like to share neither does arthra plura he's a distant relative of modern millipedes but as long as a car he can rear up tall enough to look you right in the eye although he's vegetarian his strong Jaws could still deliver a nasty bite with the rise ing Waters arthra pla's foraging leads him into dangerous territory [Music] [Music] in this Clash of the Titans the arthropods armor is his best [Music] defense unless it gets [Music] split impaled his soft innards provide a feast the lightning storm is building moving ever closer just in time the spider finds another hole a petrolacosaurus is evicted but reptiles don't need Burrows to avoid danger they have speed and stamina on their side meanwhile the spider starts to turn the h into a hunter's Lair night falls and Misa settles into her new silk lined home she tests the new trip lines they're already picking up vibrations from outside the storm is very close now lightning strikes ignite the oxygen rich air giant dragon flies are forced down from the canopy to seek shelter below an unexpected windfall for the water predators amid the chaos Misa seems safe in her bunker [Music] underground a huge fire ignited by lightning has devastated stated misa's [Music] neighborhood there are no signs of Life above ground however a petrolacosaurus managed to outrun the Flames but now he heads right into the spider's lair [Music] misa's hole was at the center of the lightning [Music] strike the reptile gets a spider barbecue the era of the giant bugs is coming to an end the climate is drying and the atmosphere is losing oxygen the monster insects and spiders can't survive the change but with their efficient hearts and waterproof skin our versatile ancestors flourish in the new dry climate Evolution takes [Music] over lacking restrictive armor means the reptiles can start to make it big their muscles and bones broaden and extend their bodies mushroom into huge new shapes and forms our distant ancestors have come a long way they've now conquered the land [Music] the world's first giant reptiles have arrived but they're not related to dinosaurs their descendants will be of a very different [Music] kind reptiles have now spread all across the globe [Music] edaphosaurus bask in the early morning sun they're 3 m long as big as hippos and like them they're vegetarians life in their new perian home is a constant battle with the elements the climate swings between seasonal streams from burning Summers to freezing [Music] Winters a new species of plant has evolved able to withstand this cold dry atmosphere primitive conifers in this harsh unpredictable World creatures must be tough and adaptable to [Music] survive the insects have shrunk since their carbon Glory Days but the giant reptiles have prospered by finding a way to regulate their body temperature edaphosaurus are sluggish in the Autumn morning chill but they'll soon warm up thanks to the huge Sail on their backs their backbone has tall spines connected by a thin membrane of blood fill skin this large surface area can lose heat fast if the aapos need to cool [Music] down while to heat up they simply turn their sails towards the sun like a solar panel amazingly these strange sail backs are related to us they're part of a very special group of creatures called mammal likee reptiles it's down to them that we have control over our body temperature [Music] today but edaphosaurus aren't the only sailb backs and now their biggest enemy is one of their own kind [Music] [Music] this is dimetrodon a vicious carnivore the biggest reptile on [Music] Earth she'd normally attack adult edaphosaurus but today she wants to avoid injury she's pregnant and almost ready to lay her eggs she finds a smaller softer Target [Music] this was only a mock charge a tactic to dispers the group and expose the vulnerable young the panicking edaphosaurus flush their sails with blood flashing an eye spot to distract the Predator's attention from their vulnerable head but dimetrodon can see through their disguise she locks on to her [Music] victim as well as her sheer size and power Dietra has a killer Edge as a mammal-like reptile she's evolved specialized teeth inzer Shear off chunks of Flesh serrated canines cut and slice we humans have inherited these same meate eating teeth we have a smaller version in our mouths today the young aapos didn't stand a chance this is a crucial kill for the dimetrodon before she lays she needs to eat enough to last her for the next 7 months to boost her baby's chances of survival she's evolved a basic form of Parental care guarding her eggs but the smell of blood has attracted more dimetrodon highly aggressive males the female knows better than to defend her Kill by the time the group has finished there'll be nothing left but bones while Lions today consume 70% of a carcass dimetrodon eat 90 but they'll only eat intestines after shaking out the waste inside dung is one thing a dimetrodon can't [Music] stomach the female has built a nesting mound of Earth and wood [Music] inside she digs a deep [Music] burrow and starts to lay her eggs [Music] she covers her brood carefully ready to begin her guard Duty egg thieves lurk in the shadows like this carnivorous amphibian but he's too small to make a full frontal attack he'll have to bite his time until the female turns her back the mother must also constantly monitor the nest [Music] temperature temperature control is vital for reptiles even before they [Music] hatch the mother piles on more Earth if the babies are too cold and will remove a layer if they're too warm otherwise the babies will [Music] die it's going to be a long 7 months [Music] the months pass and Autumn becomes a bitterly cold winter [Music] the landscape is transformed an eerie silence descends as All Creatures seek shelter still the female keeps her vigil getting weaker all the time from lack of food this is the most critical time for her Young The Nest temperature can plummet to dangerous levels many of the young may never hatch [Music] out then finally winter melts into spring in the morning's warmth the aapos feed on the thriving conifers these trees contain an early form of antifreeze which has helped them to withstand the cold winter they also have extremely tough Hardy leaves making them particularly difficult to digest to grind down these tough mouthfuls the aapos have developed a specialized jaw and teeth they're some of the first creatures with this adaptation digesting plants is a more challenging task than meat and the adaphostin [Music] [Music] they carefully shade their sails from the heat but there's much activity at the nesting mind and it's not the mother who's digging another female is desperate to lay her eggs if she takes over the M she'll dig out and kill the incubating young already inside the resident mother may be weak but she won't give up her nest without a fight [Music] it's a battle neither can afford to lose [Music] [Music] next morning just one female remains at the nesting Mound it's the resident mother she's managed to wrestle off her rival but not without a sacrifice she won't be able to defend her eggs or herself for much longer and the thieving amphibian is poised to seize his chance as summer arrives the aapos are thriving in the [Music] heat the young have grown and test out their new found strength [Music] [Applause] [Music] but the mother dimetrodon has reached the end of hers so weak she's helpless as another Intruder attacks her nest luckily this large male has got his teeth into something more substantial than her Young the amphibian the precious eggs are safe and ready to hatch the mother can hear them squeaking she's achieved her goal but at this moment her maternal bond is severed unlike her mammal descendants she won't nurture her young her Instinct now is to save herself by finding food [Music] without their mother's protection the babies will have to be ready to go It Alone they take their first steps into a perilous world and must make a Mad Dash for the safety of the [Music] trees a danger in a familiar form awaits them adult dimetrodon are cannibals [Music] not all babies are helpless some already instinctively know how to defend themselves they roll in dunk something the adults can't stand repelling their pursuers long enough to get a head start one adult is driven on by hunger and Desperation the mother she'll weed out weaker babies straight away which helps the strong ones and her species as a whole survive and now the reptiles evolve to tighten their grip on [Music] land their legs straighten and lengthen holding them more upright and giving them [Music] speed their backbones and muscles get stronger and they even start to look like mammals to house a larger brain their skull bones expand into an enormous head and out of their jaws thrust huge sharp teeth a new age of specialist reptiles has dawned but after 270 million years of evolution the war our distant ancestors have waged so long is much more than a battle between predator and [Music] prey the whole planet is entering a different kind of Crisis one that will decimate the monster reptiles and wipe out 90% of life on Earth all the continents on earth have now drifted together to create one giant land mass called Pangia and at its Center lies the largest desert the world has ever seen it's a brutal world where animals have to be especially tough perfect for reptiles this is a one time Siberian scutosaurus a distant ancestor of turtles although he has no shell his back is covered in hard bony plates and just as well these sand dunes hide a fearsome Predator scutosaurus normally travel in herds but this old male's got left behind and his Keen nose senses Danger once he tires he's vulnerable [Applause] his attacker is a carnivorous [Music] gorgonopsid she's fast powerful and equipped with deadly weapons no Hunter has had before exhausted trapped and weakened by his wound the old scooter Taurus has no fight left all he can do is wait for the killer [Music] [Applause] [Music] [Applause] [Music] blow the Gorgan oid's huge Jaws hold a pair of fangs 12 cm long she has evolved the world's first saber teeth a Lethal Weapon some mammal Predators will later [Music] use in this harsh landscape the reptiles biggest battle is now with the elements a massive surge in volcanic activ ity is beginning to superheat the atmosphere creating the highest temperatures life on Earth has ever known each year the deserts spread even here in Siberia far north of the equator animals are forced to Cluster around any lasting source of water no matter how [Music] small the huge female gorgonopsid has come looking for a drink to wash down the scutosaurus and even smaller gorgonopsids will do well to keep out of her way 5 m long from nose to tail she's the top predator on Earth there'll be nothing to rival her until the dinosaurs evolve in 30 million years time but unlike the dinosaurs these early reptiles are more closely linked to our ancestors mammals than to lizards and crocodiles they don't have fur but they've already evolved scent glands in their skin this way everyone can tell when the giant gorgonopsid is around despite the presence of these heavy weights smaller creatures also eek out a living around the water hole dicodon a Hardy little burrower just half a meter long they live as pears in spiral Burrows which remain cool even in the desert heat like the large Predators outside dicodon are distant reptile relatives of mammals and although it will be 30 million years before the first true mammals appear there are already family resemblances in particular his hearing is linked to Tiny bones in his lower jaw one day these will evolve into our middle ear bones something no reptile has several pairs of diadon live around the water hole but this is not a colony they compete furiously for the sparse vegetation that is their food this frequently leads to confrontation [Music] these clashes are one reason why both males and females sport a pair of short tusks there is however one big advantage to living in a crowd if a neighbor spots danger everyone soon knows about it a gorgonopsid has come to [Music] [Music] investigate a single snap of those enormous Jaws would crush diadon if they could get a [Music] grip but it's not always size that counts [Music] these tiny mouthfuls are more trouble than they're [Music] worth the Gorgon opset knows that if she hangs around the water hole for long enough eventually larger prey will come to her [Music] there is another unseen resident of this water hole a monster much less suited than the reptiles to the changing climate a fugitive from when this desert world was Lush and green it lies in Ambush underwater like a crocodile a giant amphibian labyrinthodont but pound for pound this female's picked the wrong [Music] target the amphibian Ambush attempt was probably driven by sheer desperation for Generations this water hole has supported a wide range of animals including several other labyrinthodonts but this one is the last and as the water she depends on disappears she's trapped the wet season arrives but there's no rain with life under such pressure species are dying out at a rate that won't be matched until humans evolve in 250 million years time the water hole is now no more than a large puddle diadon are more adaptable than most they can dig deeper to escape the heat carving out tunnels in the rock hard mud but the giant amphibian is in big trouble and as she grows weaker her enemy watches and waits it's a deadly game of cat and mouse but life here is about to change for [Music] [Music] [Music] everyone a migrating her of scutosaurus has sniffed out the water hole it's possible they smelt the water several miles away and this could well be the first drink they've had in 6 months the desert plants are a poor source of nutrients but these large reptiles are designed to squeeze out every ounce although they cannot chew their huge stomachs hold Stones they've picked up from the desert these help grind the vegetation so their digestive juices can get to work the tough little dicodon are used to dodging danger but the gorgonopsid now keeps her distance even she dare not attack such a large armored herd it's a standoff it turns out the scutosaurus are a bigger threat to life around the water hole than the Predators within a few days they have drunk it dry and moved on once again in their Eternal search for [Music] food they represent the plight of all creatures on the continent of Pangia the global Dr is now obliterating millions of years of evolution life everywhere is on the brink for animals that do not migrate the situations reaching a crisis point [Music] hunger drives the gorgonopsid back to the diadon and this time she tries to dig them out but the diadon hard work pays off their tunnel in the sunbaked earth is deep enough to keep them safe instead the gorgonopsids nose leads her back to the dried up water hole she senses things are not as lifeless as they [Music] seem the giant amphibian just before the water hole dried up she must have burrowed into the damp mud forming a cocoon around herself in a last ditch attempt to sit out the drought but in her torpid State she's helpless as the gorgonopsid feasts [Applause] [Music] eventually storm clouds gather but instead of rainwater they bring [Music] sand the sandstorm sweeps in burying The Water Hole completely [Music] the vast pangian deserts continue to spread snuffing out entire ecosystems even the mighty gorgonopsid has at last succumbed with no prey even she could not survive mummified in the sand this monster will soon be nothing but [Music] dust over the next few million years the earth will suffocate under a stagnant blanket of heat sparking a mass extinction even greater than the one that will destroy the Dinosaurs the future belongs to a tiny group of survivors small and adaptable enough to sit it out the dicodon carry on digging throughout the drought this pair has Unearthed plant tubers which hold enough water and nutrients to keep them going for several months as millions of years go by the climate shifts again and the reptiles are among the first to recover and repop populate the empty Earth from creatures like little diadon larger stronger herbivores evolve these tough forerunners of mammals seem poised to seize control for good but they are in fact set to play out their final scene [Music] the dawn of the Triassic era and the Earth has only just begun to show signs of recovery the deserts have stopped growing and huge forests of primitive Conifer start to recolonize the [Music] land in these new forests plant eaters recover first one in particular like most of the large reptiles they may resemble d URS but lystrosaurus are more closely linked to mammals and to us astonishingly their vast herds make up more than half of all life on Earth never again will a single species do so well deep within the forests though a rival is evolving a new type of animal destined to change the face of life on Earth meet upup par carrier a tiny insect eater he may not look much of a threat to the dominant reptiles but the key to his success is in his hip the way his thigh bone is attached allows him to run on two legs freeing his hands this kind of agility has never been seen before in reptiles and gives you parara an edge upup Park area will lay the foundations for a new group of reptiles the dinosaurs Giants such as Tyrannosaurus and diplodicus can all Trace their family tree back to this little insect hunter in the Triassic forests the monster herds of lystrosaurus Hoover up so much vegetation that they constantly migrate to find fresh food they follow the seasonal rains and each here in Antarctica this brings them to the edge of a huge [Music] escarpment the only way down for these cumbersome animals is through a deep ravine [Music] the herd moves mostly at night and come Sunset they begin the dangerous descent it will take several hours for all of them to pass through the Ravine and in some parts there's only space to move in single file which leaves them very vulnerable [Music] lystrosaurus have sharp eyesight and a very good sense of smell but in these cramped conditions it's hard to spot trouble ahead they're being watched by a vicious nocturnal Hunter a theophan lystrosaurus are strong opponents but this Hunter doesn't rely on power to make a kill the attack is Swift and seems to have been unsuccessful but this predator's secret weapon is a poisonous bite its venom is more lethal than a black man ambers and it quickly floods the lystrosaurus bloodstream all the theophan have to do is wait for it to take [Music] effect the victim collapses but the herd moves on without concern they have no social bonds the Theos ofans close in for the [Music] kill Dawn at the foot of the escarpment and here the lystrosaurus will face their biggest challenge yet they need to cross a river but its banks are lined with open Jaws chasmosaurs are the earliest ancestors of crocodiles and alligators their strange overbite means once they get their teeth into a victim there is no chance of Escape they don't normally Gather in such numbers but they're here for a special event the annual migration of the lystrosaurus if you're a upup par areer the river is not a great place for hunting insects but he has speed on his side as the sun rises the chasmosaurs are drawn towards the water some of them haven't eaten since the lystrosaurus last passed this way a year ago now they sense it's time to feed again the front of the vast lystrosaurus herd finally reaches the river they're strong swimmers but drowning is not the danger here they linger at The River's Edge reluctant to go in for reptiles they have relatively large brains and they may remember what happened last year but with more lystrosaurus arriving all the time the backlog will soon force them [Music] in on the other side Lush grazing beckons and eventually the first one takes the plunge [Music] a strong swimmer he quickly makes it to the other side but with the Steep Banks he still got to find a place where he can get ashore and every extra Moment In The Water increases the [Music] risk more and more lystrosaurus we strike out for the other [Music] side but now the Predators are homing [Music] in the first swimmer has made it and clambers ashore but many of the herd now entering the water will not be so lucky [Music] [Music] [Applause] [Music] despite the conage the herd is soon reforming on the other [Music] side the Predators are quickly sated and exhausted although many lystrosaurus are dead it's still only a small proportion of the herd but the brief Glory Days of these strange mammal-like reptiles will soon be [Music] gone as life continues to revive after the peran extinction the battle for survival intensifies youup par area may only have had a walk-on part so far but he's about to Herald a new age of lethal [Music] [Music] Predators his descendants will be known as the most notorious Monsters of them all [Music] Dinosaurs the unique ability to stand upright and the agility this allowed gives the early dinosaurs a Competitive Edge over our four-legged mammal-like ancestors repressed by these Swift Killers our ancestors are reduced to small creatures hiding in the shadows their time will come but for the next 170 million years the world belongs to the dinosaurs [Music] [Applause] [Music]