{1108}{1210}When the dinosaurs disappeared|so too did the gigantic
{1198}{1306}marine reptiles that once|terrorised the oceans.
{1304}{1418}For almost twenty-five million|years there was nothing around
{1404}{1454}to eat the sharks.
{1541}{1659}But there are now awesome new|monsters of the deep.
{1916}{1997}The giant whales have arrived.
{1994}{2115}Forget the gentle filter feeders|of the twenty-first century.
{2099}{2222}These days every whale is a killer.
{2680}{2796}lt is the late Eocene and the|world is still a hot one.
{2783}{2884}However it is drier than before|and so where once the land
{2872}{2947}was completely covered|in lush rainforest
{2939}{3017}there are now more open spaces.
{3009}{3088}Freed from the constraints of|living in dense forest
{3080}{3162}some mammals have started|to get larger.
{3155}{3268}Here on the scrub plains|big is beautiful.
{3409}{3471}These changes have not|suited everyone.
{3465}{3556}The large killer birds are no|longer much in evidence,
{3545}{3672}replaced on most continents|by fearsome new mammal predators.
{3791}{3901}Like dinosaurs before them mammals|dominate the planet.
{3887}{3988}But they are about to undergo|their severest challenge.
{3987}{4098}The climate change the world|has seen so f ar is mild
{4085}{4164}compared to what is coming.
{4241}{4355}This programme is about the|beginning of primate chaos
{4400}{4494}The problem starts not on land|but in the ocean and affects
{4483}{4564}even the mightiest of mammals.
{4602}{4708}This is the legendary Tethys|a tropical sea that
{4695}{4797}stretches almost half way round|the world and has connected
{4785}{4902}Asia with the Atlantic since the|time of the dinosaurs.
{4894}{5021}lt is now home to one of the|mammal's biggest success stories.
{5273}{5405}Basilosaurus - eighteen metres|of predatory whale.
{5434}{5527}Four times the length of|a Great White Shark.
{5516}{5599}This female weighs sixty tons
{5738}{5913}lncredible to think then their ancestors|were tiny furry shrew like animals
{5888}{5940}that lived in trees.
{6312}{6410}At this time of year off|the coast of the Northern Tethys
{6399}{6478}Basilosaurus gather to mate.
{6760}{6867}A female is being eagerly pursued|by several males.
{6856}{6976}But it is the eldest and biggest|male that she chooses to mate with
{7035}{7169}Mating is not an easy task for two|such huge free floating animals
{7151}{7219}they need a little extra help.
{7212}{7312}As the successful male manoeuvres|into position he calls upon
{7300}{7412}one small legacy of their distant|land ancestors.
{7564}{7670}Basilosaurus retain two|tiny back legs.
{7657}{7729}These are useless for walking|or even swimming,
{7722}{7800}but they are used to help lock|their long narrow bodies
{7792}{7856}together during mating.
{7850}{7964}The whales of the future will|lose these legs altogether.
{8444}{8537}The courtship is over but as|it will turn out,
{8526}{8622}a natural disaster that is|looming is about to make things
{8611}{8691}very tough indeed for|marine life.
{8777}{8875}This female's f ate is being|influenced by events f ar f ar
{8863}{8929}away in the Antarctic.
{8928}{9014}For the first time in hundreds of|millions of years the sea
{9003}{9140}is freezing at the Poles, throwing|ocean currents into turmoil.
{9172}{9270}For a whale that needs on average|eighty kilograms of food a day,
{9258}{9368}the slightest change of fish|stocks is bad news.
{9364}{9458}She is at the top of a food chain|that is about to collapse and
{9447}{9535}she has just become pregnant.
{9783}{9892}The ocean currents are also|starting to disrupt the climate
{9878}{9990}and have already affected weather|patterns along the Tethys coastline.
{9977}{10089}Many areas used to high rainf all|have suffered prolonged
{10074}{10117}drought this year.
{10209}{10360}Despite these problems life|ploughs on as best it can.
{10443}{10536}But the drought can have some|pretty nasty side-effects.
{10531}{10621}This is Andrewsarchus, a huge|carnivore as tall as a horse
{10611}{10689}and weighing close to a ton.
{10688}{10776}Normally he wanders inland in|search of food,
{10765}{10854}but the drought has driven him|onto the beach.
{10867}{10970}Bad news for the exhausted turtles|struggling back to the water
{10958}{11009}after a night laying eggs.
{11063}{11122}At first the Andrewsarchus seems|a little unsure of
{11117}{11209}what to do with these curious|shelled creatures.
{11302}{11359}He is more used to picking|over the carcasses
{11355}{11409}of giant herbivores.
{11474}{11551}Despite appearance|Andrewsarchus is not related
{11543}{11630}to modern scavengers like dogs|or hyenas.
{11623}{11731}Bizarrely he has hooves on his|feet instead of claws.
{11765}{11843}ln f act his nearest modern|relatives are hoofed
{11834}{11905}animals like sheep and goats ...
{11999}{12123}He is in a sense a sheep|in wolf's clothing.
{12120}{12248}He is also the largest mammal|carnivore ever to walk the earth.
{12233}{12336}His huge one metre long jaws are|designed to crush anything,
{12329}{12441}so the turtle's main defence|is of little use.
{12754}{12896}During droughts scavengers often do well|but in the long run the hoofed
{12876}{12981}predators will not adapt quickly enough|to changes in the climate.
{12969}{13039}He is the last of a dying breed.
{13176}{13272}Months have passed and the erratic|ocean currents have disturbed
{13261}{13363}the fish stock so much that|the female Basilosaurus is searching
{13349}{13464}for food hundreds of miles from her|usual hunting grounds.
{13469}{13572}Four months pregnant, her situation|has become critical.
{13559}{13673}She is now forced to hunt|in the most unlikely places.
{13726}{13814}Lining the southern edges of|the Tethys are endless
{13805}{13867}expanses of mangrove swamp.
{14093}{14213}ln the Eocene it's a vast thriving|network of waterways,
{14203}{14281}but believe it or not you are looking|at what will become one of
{14273}{14405}the driest areas on the planet|the Sahara Desert.
{14599}{14740}lt's hardly a classic hunting ground|for an ocean-going whale,
{14721}{14836}but she is desperate and there is|prey here of a sort.
{14919}{15045}ln the labyrinth of tidal channels|her size is a real handicap,
{15028}{15088}but hunger draws her in.
{15144}{15226}Watching from the branches|above are primates.
{15219}{15339}These are Apidium that live in highly|social groups and word quickly
{15324}{15399}gets around when a threat is spotted.
{15601}{15702}Other creatures here are oblivious|to the new danger.
{15743}{15894}The amphibious mammal Moeritherium|is too large to be bothered
{15873}{15932}by the usual predators|such as crocodiles,
{15928}{16067}so they ignore the chattering primates|and return to the business of eating.
{16084}{16203}The Apidium move away from the channel|and continue through the mangroves
{16188}{16248}looking for fruiting trees.
{16245}{16338}Because different trees fruit at|different times they often have
{16326}{16377}to cross the waterways.
{16374}{16441}This is a very risky activity.
{16435}{16516}There are sharks and crocodiles|to worry about ...
{16517}{16589}and now there is a whale as well.
{16888}{16985}lt's a leap of f aith,|but leaping is one thing
{16974}{17033}Apidium are very good at.
{17145}{17245}The whale is frustrated for the moment.
{17437}{17539}With the rising tide however some|waterways become too wide to
{17527}{17642}jump and the Apidium have to find more|hazardous ways across closer
{17628}{17678}to the water.
{18081}{18148}Today their nightmare came true.
{18166}{18200}lt was a shark.
{18288}{18344}They certainly won't cross now,
{18341}{18414}they'll have to wait for|the tide to go down.
{18799}{18909}By contrast the water isn't usually|dangerous for the Moeritherium.
{18898}{18956}They spend most of their day here.
{19006}{19107}Although they are shaped like hippos|and look a bit like pigs,
{19095}{19168}Moeritherium are related to neither.
{19193}{19270}Look closely though and the|Moeritherium's nose betrays
{19262}{19329}its true f amily connection.
{19322}{19425}The nostrils and lip have joined|together to become one dextrous
{19413}{19507}muscular unit which helps|them forage for food.
{19504}{19580}This is in f act a type of trunk.
{19573}{19687}These benign herbivores are early|relatives of the elephant.
{19699}{19835}At around two hundred kilograms|they are too big for the sharks.
{19882}{19965}One Moeritherium heads off|for pastures new ...
{20022}{20148}But he is heading straight for|the jaws of the female Basilosaurus.
{20458}{20556}The Moeritherium scrabbles onto|dry land just in time.
{20881}{20984}But the hungry Basilosaurus|isn't about to give up yet.
{21550}{21671}Dry land and safety are only|temporary things in the mangroves.
{21847}{21950}The water still has some way to rise|and most solid ground will
{21938}{22083}become seabed in just a few hours|time as the high tide sweeps in.
{22305}{22433}The Basilosaurus will soon be able|to reach the stranded Moertherium.
{23235}{23341}ln her desperation she has attacked|too early and run aground.
{23884}{23973}By the time the whale has worked|herself free the Moeritherium
{23961}{24048}has escaped to the shallower channels|where even the starving
{24038}{24099}Basilosaurus won't follow.
{24095}{24162}For the whale, the mangroves|are turning out to be no
{24155}{24210}better than the open sea.
{24362}{24464}The Eocene El Nino continues|to wreak havoc.
{24458}{24545}The weather patterns that|animals rely on are confused.
{24547}{24657}ln the Northern Tethys the rains|have come, but six weeks
{24643}{24684}later than usual.
{24929}{25058}And then instead of lasting months|they are over in a few weeks.
{25216}{25321}ln the scrubland the rains have|finally provided new growth,
{25310}{25437}but the damage caused by the prolonged|drought has already been done.
{25478}{25583}These Brontothere herds in particular|have been hit hard.
{25570}{25693}Though distantly related to horses and|rhinos they're not much like either.
{25680}{25824}They're twice as big as modern rhinos|with brains just one third of the size.
{25805}{25862}They are not the brightest of beasts
{25941}{26037}Still they are one of the most|successful groups of mammals around,
{26025}{26123}found across the Northern Hemisphere|in herds of hundreds.
{26136}{26234}This year though some herds are|in a sorry state.
{26363}{26454}This should be a time for calving|but a high proportion
{26444}{26493}are being still-born.
{26574}{26671}The few youngsters that have survived|the drought continue to behave as
{26659}{26713}youngsters always do.
{26757}{26859}These two adolescent males practice|for adulthood, challenging one
{26847}{26949}another over as yet non existent females.
{27011}{27110}ln another difference to rhinos the|outgrowths on their noses are not
{27098}{27163}horn or hair, but bone.
{27162}{27225}These are more for show than|for head-butting.
{27219}{27296}The bone crests are f ar|too brittle for that.
{27382}{27464}The scavengers are having|a better time of it.
{27585}{27688}And Andrewsarchus is trying to harass|a mother Brontothere and get at
{27675}{27723}her dead calf.
{27750}{27826}The female though is being|fiercely protective.
{28058}{28135}lt is impossible to say whether|this mother even understands
{28125}{28173}that her calf is dead.
{28175}{28243}Like most mammals she has a very|strong bond with her
{28237}{28347}offspring and will defend it for|as long as she can.
{28491}{28569}Now a second Andrewsarchus has arrived.
{28561}{28654}lt is going to be difficult for|the mother to keep them both away.
{29009}{29109}The first Andrewsarchus seizes|its chance.
{29420}{29558}After all day defending a lost cause|the mother appears to be giving up.
{29789}{29888}The scavengers aren't used to|having to share the spoils.
{30236}{30325}As they wrestle for the calf|the mother mistakes its movement
{30315}{30375}for signs of life
{30481}{30550}She is spurred into action again.
{31084}{31183}She returns to her lonely and|fruitless vigil.
{31233}{31317}The Andrewsarchus will be back.
{31635}{31731}As the weeks pass the environmental|crisis at sea shows
{31719}{31775}no sign of easing.
{31774}{31878}lt can only be described|as an ocean f amine.
{31992}{32085}For the female Basilosaurus|who is now heavily pregnant
{32075}{32132}things are desperate.
{32152}{32236}She is getting barely enough|for herself to eat never mind
{32227}{32268}her unborn calf.
{32266}{32332}With her limited f at reserves|all but gone,
{32326}{32458}her body will soon abort her offspring|in order to preserve her own life.
{32681}{32767}Suddenly the sea around her is filled|with the bustling activity of a
{32756}{32843}group of smaller whales called Dorudon.
{32985}{33075}When Dorudon gather in numbers|it means that the females are
{33065}{33122}about to give birth.
{33172}{33291}This might look like a friendly greeting|it is anything but.
{33287}{33357}The smaller whales are mobbing|the giant, using their
{33350}{33404}numbers to try and force her away.
{33419}{33534}Basilosaurus preys on their young|and somewhere nearby must be the
{33519}{33586}Dorudon's calving ground.
{33707}{33800}lt appears as though she has been|driven to the seabed.
{33790}{33868}But there is method in her madness.
{33962}{34063}She has to do something that is more|important than ever if her unborn
{34052}{34126}calf is to survive.
{34118}{34177}She must scratch.
{34374}{34478}By dragging herself over a convenient|sandbar she can slough off
{34466}{34593}the outer layer of her skin and with|it any parasites or barnacles that
{34577}{34642}may have got a foothold.
{34787}{34864}For an animal that relies|on speed to hunt,
{34856}{34943}keeping her body sleek and|streamlined is the difference
{34932}{35021}between success and hunger.
{35019}{35102}She is ready to go hunting whales.
{35430}{35577}Every year Dorudon gather in this calm,|protected lagoon to give birth.
{35616}{35782}The first calves are appearing|just a few days old and already
{35759}{35821}in mortal danger.
{35823}{35915}The Basilosaurus has found the lagoon ...
{36028}{36126}She has been spotted and the calves|are quickly shepherded away
{36114}{36168}from the threat.
{36500}{36600}Defending together the adult Dorudon|launch aggressive attacks against
{36587}{36696}the Basilosaurus in an attempt|to drive her off.
{36758}{36853}Their efforts appear|surprisingly effective.
{36848}{36942}The Basilosaurus moves away.
{37080}{37217}Calm is restored but|it won't last for long.
{37286}{37347}This is a hungry mother.
{38066}{38145}Over the course of the next few days|the Basilosaurus returns
{38136}{38204}time after time.
{38352}{38477}The lagoon is transformed from|a sanctuary into a bloodbath
{38578}{38663}This is what it means to be|top of the food chain.
{38657}{38758}lt has taken the death of several|Dorudon calves to further the survival
{38745}{38835}of the unborn Basilosaurus.
{39690}{39797}lt has been a year since|the female Basilosaurus mated.
{39785}{39858}She is once again out in the open seas
{39940}{40025}But this time she is not alone.
{40189}{40282}Against all the odds|she has finally given birth.
{40496}{40632}Against the odds she and|her calf have survived.
{40806}{40902}Sadly what they have been through|is merely the start of the climate
{40892}{41035}chaos to follow which will end|the Eocene period and cause the largest
{41014}{41115}extinction since the death|of the dinosaurs.
{41148}{41250}As devastating as any meteor will be|the catastrophic disruption of
{41239}{41372}the ocean's currents caused|by the gradual freezing of Antarctica.
{41359}{41486}Like a gigantic El Nino only|much much worse.
{41470}{41577}Twenty percent of living things|on earth will die out.
{41607}{41772}Whales as a group will survive|but Basilosaurus and her kind
{41748}{41821}will not be among them.
{41978}{42099}Next time mammals on land go|from big to bigger.
{42085}{42148}We will walk with the lndricothere's -
{42143}{42240}...mammals that rival in size|the dinosaurs of old.
{42230}{42409}lt is a world of the big,|the bad and the ugly.