{800}{939}Imagine you could travel back|in time - to a time long before man.
{985}{1052}Back across 65 million years.
{1054}{1176}You would see huge changes|in the vegetation and the climate.
{1179}{1263}Even the surface of the Earth itself|would move
{1265}{1351}as mountain ranges are pushed up|by colliding continents.
{1650}{1748}You've reached a period in Earth's|history known as the Cretaceous.
{1750}{1813}It is a very different world.
{1815}{1933}The Himalayas do not yet exist and|the Atlantic is only half as wide.
{1935}{2033}There is no grass, only|conifer forests and fern prairies.
{2067}{2081}This is a world ruled by dinosaurs.
{2081}{2170}This is a world ruled by dinosaurs.
{2172}{2230}(Fierce roar)
{2329}{2420}Giant reptiles like Tyrannosaurus,|a five-tonne predator,
{2423}{2471}stalk the land.
{2682}{2749}In Walking With Dinosaurs,
{2751}{2878}we will show you how|these magnificent creatures live -
{2881}{2941}how they eat, fight and reproduce.
{2943}{3027}You will witness|how the forces of nature
{3030}{3129}conspire to drive these animals|to extinction.
{3306}{3421}But this series will also|take you back much further.
{3582}{3635}To the Jurassic period -|when life on Earth
{3637}{3687}was at its most spectacular.
{3718}{3733}(Low grumbling roar)
{3733}{3766}(Low grumbling roar)
{3806}{3904}The creatures here|bathe in a warm tropical climate -
{3906}{3971}there are no icecaps at the poles.
{3974}{4067}Flowers and broad-leaved trees|are yet to evolve.
{4070}{4187}In the air and on the land,|the world is dominated by reptiles,
{4189}{4266}and by far the most common|are the dinosaurs.
{4472}{4532}But they are not the only giants.
{4574}{4670}Huge pterosaurs rule the skies|and, below them,
{4672}{4778}massive marine reptiles|harvest the rich oceans.
{4943}{5051}However, first, this series|will go back even further,
{5054}{5135}to discover where|dinosaurs came from.
{5193}{5253}This is our own Earth|during the Triassic period.
{5328}{5366}There are no separate continents,
{5369}{5433}just one landmass called Pangaea.
{5433}{5534}It is a harsh place|dominated by deserts.
{5707}{5762}The Triassic has already seen
{5764}{5843}many different varieties|of ancient reptiles come and go.
{5877}{5889}But now, out of this dry wilderness,
{5889}{5930}But now, out of this dry wilderness,
{5932}{6014}has appeared something|revolutionary.
{6017}{6134}A family of reptiles destined|to shape the course of life on Earth
{6137}{6206}for the next 160 million years.
{6233}{6295}These are the first dinosaurs
{6298}{6360}and this is where our story begins.
{6742}{6795}First light across the western hills
{6795}{6867}of Earth's only continent, Pangaea.
{6869}{6917}This world has been ruled
{6919}{7035}by one group of giant reptiles|for over 50 million years.
{7037}{7133}But these ancient creatures|have had their day.
{7169}{7241}All over these lush fern prairies,
{7241}{7373}an evolutionary battle has broken|out among the newer types of reptile
{7375}{7469}for supremacy of this strange world.
{7510}{7652}0n these Triassic proving grounds,|dinosaurs are still rare,
{7654}{7764}but they are beginning to show signs|of their future success.
{7786}{7824}(Small growl)
{7961}{8081}It is the end of the wet season|and the local river is full.
{8081}{8150}But it will not remain this lush,
{8153}{8230}and ahead lies nine months|with no rain.
{8259}{8370}0ne type of reptile|has evolved to thrive in drought.
{8372}{8492}Dinosaurs like this Coelophysis|can survive on very little water.
{8494}{8633}She is also light-boned, fast,|and she is beautifully adapted...
{8633}{8684}for killing.
{9059}{9152}Dinosaurs appeared|around 10 million years before,
{9155}{9205}as small predators.
{9207}{9282}What makes them unique|is special hips and ankles
{9284}{9354}that allow them to stand|perfectly balanced on two legs.
{9404}{9517}With lightning-fast reactions,|they are built to survive.
{9519}{9553}(Loud roar)
{9593}{9653}(Trumpeting calls)
{9694}{9826}A chorus of calls signals the|arrival of a huge herd of Placerias.
{9829}{9956}They are making their way down from|the ferns for their morning drink.
{10117}{10235}These impressive one-tonne beasts|are not related to dinosaurs.
{10237}{10333}They are a much more ancient|type of reptile.
{10335}{10450}0nce there were many different kinds|of these powerful creatures,
{10454}{10571}but now the Placerias are the only|ones of their kind that remain.
{10574}{10634}They are an endangered species.
{10636}{10753}Despite their fearsome appearance,|they are actually gentle herbivores.
{10756}{10842}Their tusks are used|for digging up roots.
{10845}{10888}(Angry growling)
{10917}{11039}But on two angry males,|these tusks can make lethal weapons.
{11229}{11330}For the swift Coelophysis,|Placerias are prey.
{11359}{11438}This young female|targets the old and weak
{11438}{11488}in the slow-moving herd.
{11527}{11584}(Growling and trumpeting)
{11910}{12028}0ne day, the descendants|of dinosaurs like Coelophysis
{12031}{12077}will take over this world,
{12079}{12149}but it is their speed and agility
{12149}{12223}that gives them the edge|in the mid-Triassic.
{12364}{12479}Further downriver is one of|the Triassic's most bizarre animals.
{12482}{12561}The cynodont is a missing link|between reptiles and mammals.
{12592}{12606}As he runs, his backbone moves
{12606}{12650}As he runs, his backbone moves
{12650}{12724}from side to side like a reptile's,
{12727}{12842}but he has hair and lives|down a burrow, like a mammal.
{13001}{13085}Deep inside,|his mate sleeps on a bed of lichen.
{13087}{13178}The bond between cynodonts|is very strong -
{13180}{13226}they pair for life.
{13228}{13310}Like all land reptiles,|they lay eggs,
{13312}{13430}but after hatching, the young are|utterly dependent on their parents
{13433}{13486}and for the first three months,
{13488}{13558}feed from milk glands on the mother.
{13560}{13625}This form of reproduction|has evolved
{13627}{13697}to protect their young|from the daylight predators outside.
{13762}{13884}By day, even the father sticks close|to the safety of the burrow
{13886}{13949}and carries out domestic chores.
{13951}{14009}He only hunts at night.
{14252}{14309}In the not too distant future,
{14312}{14417}small furry mammals will evolve|from reptiles like these.
{14640}{14700}In the heat of the dry season,
{14700}{14818}the Placerias herd spreads out|over the scrubland to feed.
{14820}{14880}(Low growling)
{14915}{14979}Suddenly the warm breeze changes
{14982}{15078}and there is the scent of fear|in the air.
{15440}{15495}(Vicious growling)
{15807}{15901}Postosuchus,|a merciless ambush predator -
{15903}{15968}the largest carnivore on Earth.
{15971}{16016}(Roars )
{16117}{16237}The terrified Placerias flee,|but they are desperately slow
{16237}{16304}and one of them is mortally wounded.
{16306}{16414}Their tormentor is|a distant cousin of the dinosaurs,
{16415}{16530}but unlike them, she is|too front-heavy to run on two legs.
{16533}{16657}Yet the Postosuchus is easily fast|enough to keep pace with the herd.
{16691}{16796}Eventually, a combination|of shock and blood loss
{16799}{16856}defeats the wounded Placerias.
{17135}{17188}The carnivore's bite|has done its job.
{17212}{17306}The Placerias|is now too weak to fight
{17308}{17397}and the Postosuchus|has an easy meal.
{17620}{17692}As the weeks of the dry season pass,
{17694}{17776}only the vegetation|around the river remains lush
{17778}{17903}and this attracts exotic hunters|like this Peteinosaurus.
{17904}{17990}She is a flying reptile|who has evolved extra-long fingers
{17990}{18052}to support|her delicate wing membranes.
{18055}{18115}(Rattling call)
{18199}{18314}The river's resident|flying predators are dragonflies.
{18366}{18486}Insects like these evolved|long before the first reptiles.
{18489}{18537}0ver 100 million years ago,
{18537}{18623}some took to the air|and became aerial killers.
{18624}{18756}But in the Triassic era, these|hunters have become the hunted.
{19135}{19199}A jaw full of needle-sharp teeth
{19202}{19264}makes short work of the insect.
{19336}{19432}Peteinosaurus have evolved strong,|lightweight bones for flight,
{19435}{19529}and like the dinosaurs,|they are fast and deadly.
{19531}{19615}Reptiles are becoming|the new masters of the air.
{19754}{19836}In temperatures|of over 40 degrees centigrade,
{19838}{19886}the Placerias need lots of water
{19886}{19948}and spend more time at the river.
{19951}{20004}But the herd is nervous.
{20006}{20090}They know|this is a good place for an ambush.
{20244}{20309}The Postosuchus is not hunting.
{20340}{20400}She has recently eaten her fill
{20403}{20510}and also needs|to come down to the river to drink.
{20568}{20666}Six metres long,|heavily built with an armoured back,
{20669}{20729}she needs a huge amount of food
{20729}{20837}and, therefore, has to defend|a very large territory.
{20931}{21056}The only creature on the planet|she fears is another Postosuchus.
{21142}{21195}(Loud, rasping roar)
{21444}{21530}It is the middle of the dry season,|months since any rain.
{21554}{21648}Across the scrubland,|smaller rivers are drying out.
{21651}{21759}In one, a Peteinosaurus risks|a cooling bath.
{21853}{21917}He constantly checks for danger.
{22191}{22244}The cynodonts lie secure and cool
{22246}{22315}through the hottest part of the day.
{22318}{22397}But no animal here is truly safe.
{22501}{22590}The female Coelophysis has picked up|the scent of their bedding.
{22592}{22655}Soon she is exploring|the entrance...
{22657}{22719}and she is not alone.
{22899}{22945}(Puppy-like growling)
{23000}{23098}Clearly these dinosaurs|have not met cynodonts before.
{23332}{23413}Nearby, the Placerias|search for moist roots
{23416}{23461}beneath the drying ferns.
{23631}{23708}The Postosuchus|once again needs food.
{23710}{23797}But her last attack left her|with a tusk wound on her thigh -
{23799}{23905}a severe handicap|for such a heavily-built creature.
{24052}{24167}The Placerias herd spots her|before she can set an ambush
{24169}{24227}and they mount an aggressive|defence.
{24229}{24289}(Angry roaring)
{24292}{24404}She will get no food here,|and in such a competitive world,
{24407}{24467}her wound may yet prove fatal.
{24527}{24587}Evening, and in the burrow,
{24590}{24683}the cynodonts prepare|for a night of hunting.
{24686}{24746}The young are more developed now
{24748}{24811}and starting to move about the nest,
{24813}{24866}but they are still vulnerable.
{24868}{24909}It'll be two months
{24911}{24995}before they can do without|their parents' protection.
{25074}{25170}The adult male|checks the coast is clear.
{25502}{25608}An inquisitive youngster follows|him to the end of the burrow.
{25874}{25931}(Squealing)
{25960}{26008}(Cynodont barks )
{26010}{26121}Too late, the male responds|to his squealing pup.
{26337}{26409}Again, he drives the dinosaurs away,
{26412}{26481}but this time, they don't go far.
{26541}{26601}Nearby, a thirsty male Postosuchus
{26604}{26697}has invaded|the wounded female's territory.
{26699}{26771}But this withered|Triassic landscape
{26775}{26844}cannot support two giant predators|in one dry valley.
{27408}{27477}The female is too weak to fight.
{27553}{27613}After dominating her territory|for a decade,
{27615}{27656}she is driven from her home.
{27687}{27701}The male uses precious water|to mark his new territory.
{27701}{27802}The male uses precious water|to mark his new territory.
{28003}{28121}Meanwhile, the Coelophysis are|starting to dig the cynodonts out.
{28193}{28296}Their situation|is becoming desperate...
{28299}{28395}as the dinosaurs|will soon expose the nest.
{28575}{28673}As the sun sets,|the pair have only one choice.
{28740}{28824}It means shattering|their unique parental bond -
{28827}{28896}they eat their own young.
{28899}{28966}This denies the dinosaurs|their food
{28968}{29062}and gives the cynodonts|the chance of escape.
{29250}{29370}Under the moonlight, they seize|the moment and abandon the hole.
{29677}{29753}In the morning,|the Coelophysis are back.
{29757}{29841}They can smell the cynodonts,|and it will take them time
{29843}{29905}to realise their work is in vain.
{30313}{30361}The dry season continues.
{30363}{30406}After the cynodont hole,
{30409}{30529}the female Coelophysis has found|something in the parched river bed.
{30532}{30626}It is a lungfish,|and the dinosaur's serrated teeth
{30628}{30724}will make short work|of its protective cocoon.
{30724}{30808}But she is not left alone|to eat it for long.
{31012}{31069}Coelophysis numbers are increasing,
{31069}{31155}and this leads to confrontations.
{31155}{31196}(Vicious squealing)
{31574}{31689}The pressure of numbers also brings|other changes in behaviour.
{31806}{31849}Under the merciless sun,
{31852}{31943}a flock of Coelophysis|has united for a kill.
{31957}{32053}The wounded female Postosuchus|has lost the use of her back legs.
{32054}{32143}However, her mighty jaws|could still tear a dinosaur apart.
{32709}{32714}The great carnivore's|strength fails.
{32715}{32774}The great carnivore's|strength fails.
{32830}{32914}All the Postosuchus's|heavy armour and muscle
{32916}{33012}are no more than food|for the agile little dinosaurs.
{33014}{33086}Their long snouts and nibbling teeth
{33089}{33146}can reach under her thick scales.
{33146}{33208}They eat her from the inside out.
{33814}{33857}The rains are late,
{33859}{33946}and now the real test|for survival begins.
{33948}{34017}As vast areas turn into red desert,
{34020}{34135}the Placerias are driven to migrate|in search of water.
{34400}{34467}But in this extreme drought,
{34469}{34577}dinosaurs have a crucial advantage|over other reptiles.
{34579}{34673}When they excrete,|they waste very little water.
{34733}{34800}Nowhere is this advantage more|obvious than by the shrunken river.
{34836}{34850}Coelophysis are gathering|in huge numbers,
{34850}{34913}Coelophysis are gathering|in huge numbers,
{34915}{34970}and in years of hardship like this,
{34974}{35036}it is the dinosaurs|that win through.
{35038}{35139}There is little room for other|reptiles, and without prey,
{35142}{35204}the dinosaurs swiftly|turn on each other.
{35273}{35331}Cannibalism is common.
{35412}{35508}The Triassic is pushing life|to its limits.
{35740}{35826}Night reveals dinosaurs|are not the only animals
{35826}{35903}that have managed to cling on.
{35903}{35979}The cynodonts have survived|their brush with death
{35982}{36068}and dug another burrow|hidden in some dried ferns.
{36070}{36178}0nce again,|the male is hunting in the darkness.
{36207}{36255}(Growling, animal squeals)
{36341}{36404}He has caught|the only common prey -
{36460}{36508}a baby Coelophysis.
{36683}{36697}(Thunder rumbles )
{36697}{36752}(Thunder rumbles )
{36942}{37002}After nine months of drought,
{37004}{37064}at last the rains have arrived.
{37863}{37947}Soon, the thirsty scrublands|are soaking.
{38291}{38423}In her burrow, the female cynodont|has laid a fresh clutch of eggs.
{38425}{38524}0ne day in the future, this strategy|of investing in their young
{38526}{38598}will pay off|for their mammalian descendants.
{38598}{38694}But as mammals evolve|over the next 160 million years,
{38697}{38769}they'll only survive|as a few small species,
{38772}{38872}clinging on at the edge|of a world dominated by dinosaurs.
{38930}{39026}0utside,|that future is already arriving.
{39088}{39194}The female Coelophysis|has survived the drought,
{39196}{39254}along with many of her kind.
{39316}{39436}But they have also been joined|by another type of dinosaur.
{39509}{39574}(Low, rumbling call)
{39749}{39792}A huge herd of Plateosaurus
{39794}{39866}has been drawn to the swollen river.
{39868}{39914}It is hard to believe that these|beasts are related to Coelophysis,
{39916}{39957}but these are|plant-eating dinosaurs.
{40106}{40187}Their size is the key|to their success,
{40191}{40323}and at four tonnes, they are|simply too big to be threatened.
{40404}{40490}This is the shape of things|to come -
{40493}{40543}the age of the dinosaurs has dawned.
{41220}{41268}20 million years later,
{41271}{41347}extinction wiped out|thousands of species of reptile,
{41350}{41431}but the dinosaurs|went from strength to strength.
{41434}{41556}Carnivores grew to enormous sizes,|but their prey got even bigger.
{41558}{41614}In the next programme,
{41617}{41686}we meet the giants of the Jurassic.