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00:00Transcribed by ESO, translated by —
00:30When the dinosaurs disappeared, so too did the gigantic marine reptiles that once terrorized the oceans.
00:52For almost 25 million years, there was nothing around to eat the sharks.
01:00But there are now awesome new monsters of the deep.
01:16The giant whales have arrived.
01:20Forget the gentle filter feeders of the 21st century.
01:25These days, every whale is a killer.
01:30It is the late Eocene, and the world is still a hot one.
01:51However, it is drier than before, and so where once the land was completely covered in lush rainforest, there are now more open spaces.
02:01Freed from the constraints of living in dense forest, some mammals have started to get larger.
02:07Here on the scrub plains, big is beautiful.
02:10These changes have not suited everyone.
02:19The large killer birds are no longer much in evidence, replaced on most continents by fearsome new mammal predators.
02:26Like dinosaurs before them, mammals dominate the planet.
02:36But they are about to undergo their severest challenge.
02:39The climate change the world has seen so far is mild compared to what is coming.
02:45This program is about the beginning of climate chaos.
02:56The problem starts not on land, but in the ocean, and affects even the mightiest of mammals.
03:02This is the legendary Tethys, a tropical sea that stretches almost halfway around the world, and has connected Asia with the Atlantic since the time of the dinosaurs.
03:16It is now home to one of the mammals' biggest success stories.
03:20Bacillosaurus, 18 meters of predatory whale.
03:38Four times the length of a great white shark.
03:41This female weighs 60 tons.
03:43Incredible to think, then, their ancestors were tiny, furry, shrew-like animals that lived in trees.
03:57At this time of year, off the coast of the northern Tethys,
04:17Bacillosaurus gather to mate.
04:27A female is being eagerly pursued by several males, but it is the eldest and biggest male
04:37that she chooses to mate with.
04:42Mating is not an easy task for two such huge free-floating animals.
04:47They need a little extra help.
04:49As the successful male maneuvers into position, he calls upon one small legacy of their distant
04:55land ancestors.
04:57Bacillosaurus retain two tiny back legs.
05:07These are useless for walking or even swimming, but they are used to help lock their long,
05:11narrow bodies together during mating.
05:14The whales of the future will lose these legs altogether.
05:27The courtship is over, but as it will turn out, the natural disaster that is looming is about
05:44to make things very tough indeed for marine life.
05:51This female's fate is being influenced by events far, far away in the Antarctic.
05:57For the first time in hundreds of millions of years, the sea is freezing at the poles, throwing
06:03ocean currents into turmoil.
06:05For a whale that needs on average 80 kilograms of food a day, the slightest change in fish stocks
06:13is bad news.
06:14The ocean currents are also starting to disrupt the climate, and have already affected weather patterns along the Tethys coastline.
06:34Many areas used to high rainfall have suffered prolonged drought this year.
06:47But the drought can have some pretty nasty side effects.
07:01This is Androsarchus, a huge carnivore as tall as a horse and weighing close to a tonne.
07:08Normally, he wanders inland in search of food, but the drought has driven him onto the beach.
07:15Bad news for the exhausted turtles struggling back to the water after a night laying eggs.
07:23At first, the Androsarchus seems a little unsure of what to do with these curious shelled creatures.
07:31He is more used to picking over the carcasses of giant herbivores.
07:40Despite appearances, Androsarchus is not related to modern scavengers like dogs or hyenas.
07:45Bizarrely, he has hooves on his feet instead of claws.
07:51In fact, his nearest modern relatives are hoofed animals like sheep and goats.
07:56He is, in a sense, a sheep in wolf's clothing.
08:05He is also the largest mammal carnivore ever to walk the earth.
08:10His huge one-meter-long jaws are designed to crush anything, so the turtle's main defense is of little use.
08:16During droughts, scavengers often do well, but in the long run, the hoofed predators will not adapt quickly enough to changes in the climate.
08:37He is the last of a dying breed.
08:47Months have passed, and the erratic ocean currents have disturbed the fish stock so much that the female Bacillosaurus is searching for food hundreds of miles from her usual hunting grounds.
08:57Four months pregnant, her situation has become critical.
09:03She is now forced to hunt in the most unlikely places.
09:09Lining the southern edges of the Tethys are endless expanses of mangrove swamp.
09:14In the Eocene, it's a vast thriving network of waterways.
09:28But believe it or not, you are looking at what will become one of the driest areas on the planet.
09:34The Sahara Desert.
09:35It's hardly a classic hunting ground for an ocean-going whale, but she is desperate.
09:50And there is prey here of a sort.
09:57In the labyrinth of tidal channels, her size is a real handicap, but hunger draws her in.
10:06Watching from the branches above are primates.
10:09These are apidium that live in highly social groups, and word quickly gets around when a threat is spotted.
10:24Other creatures here are oblivious to the new danger.
10:27The amphibious mammal, Myrotherium, is too large to be bothered by the usual predators, such as crocodiles.
10:38So they ignore the chattering primates, and return to the business of eating.
10:43The apidium move away from the channel, and continue through the mangroves looking for fruiting trees.
10:49Because different trees fruit at different times, they often have to cross the waterways.
10:55This is a very risky activity.
10:58There are sharks and crocodiles to worry about.
11:01And now there is a whale as well.
11:03It's a leap of faith, but leaping is one thing apidium are very good at.
11:21The whale is frustrated, for the moment.
11:38With the rising tide, however, some waterways become too wide to jump,
11:42and the apidium have to find more hazardous ways across, closer to the water.
12:04Today their nightmare came true.
12:07It was a shark.
12:12They certainly won't cross now.
12:14They'll have to wait for the tide to go down.
12:33By contrast, the water isn't usually dangerous for the Myrotherium.
12:37They spend most of their day here.
12:38Although they are shaped like hippos, and look a bit like pigs,
12:44Myrotherium are related to neither.
12:48Look closely though, and the Myrotherium's nose betrays its true family connection.
12:53The nostrils and lip have joined together to become one dextrous muscular unit,
12:58which helps them forage for food.
13:00This is in fact a type of trunk.
13:03These benign herbivores are early relatives of the elephant.
13:06At around 200 kilograms, they are too big for the sharks.
13:15One Myrotherium heads off for pastures new.
13:19But he is heading straight for the jaws of the female Bacillosaurus.
13:24The Myrotherium scrabbles onto dry land just in time.
13:25The Myrotherium scrabbles onto dry land just in time.
13:29The Myrotherium scrabbles onto dry land just in time.
13:30The Myrotherium scrabbles onto dry land just in time.
13:42The Myrotherium scrabbles onto dry land just in time.
13:43The Myrotherium scrabbles onto dry land just in time.
13:44But the hungry Bacillosaurus isn't about to give up yet.
13:58Dry land and safety are only temporary things in the mangroves.
14:17The water still has some way to rise and most solid ground will become seabed in just a few hours time as the high tide sweeps in.
14:42The Bacillosaurus will soon be able to reach the stranded Myrotherium.
14:57The Bacillosaurus музы ranging from to the
15:13In her desperation, she has attacked too early and run aground.
15:43By the time the whale has worked herself free, the Myrotherium has escaped to the shallower channels, where even the starving Bacillosaurus won't follow.
16:03For the whale, the mangroves are turning out to be no better than the open sea.
16:13The Eocene El Niño continues to wreak havoc.
16:18The weather patterns that animals rely on are confused.
16:22In the northern Tethys, the rains have come, but six weeks later than usual.
16:37And then instead of lasting months, they are over in a few weeks.
16:43In the scrubland, the rains have finally provided new growth, but the damage caused by the prolonged drought has already been done.
16:59These Brontothera herds in particular have been hit hard.
17:02Though distantly related to horses and rhinos, they are not much like either.
17:07They are twice as big as modern rhinos, with brains just one third of the size.
17:12They are not the brightest of beasts.
17:14Still, they are one of the most successful groups of mammals around, found across the northern hemisphere in herds of hundreds.
17:24This year, though, some herds are in a sorry state.
17:28This should be a time for calving, but a high proportion of being stillborn.
17:43The few youngsters that have survived the drought continue to behave as youngsters always do.
17:50These two adolescent males practice for adulthood, challenging one another over as yet non-existent females.
17:57In another difference to rhinos, the outgrowths on their noses are not horn or hair, but bone.
18:06These are more for show than for head butting.
18:08The bone crests are far too brittle for that.
18:11The scavengers are having a better time of it.
18:23And Androsarchus is trying to harass a mother Brontothera and get at her dead calf.
18:30The female, though, is being fiercely protective.
18:41It is impossible to say whether this mother even understands that her calf is dead.
18:47Like most mammals, she has a very strong bond with her offspring and will defend it for as long as she can.
19:00Now a second Androsarchus has arrived.
19:02It is going to be difficult for the mother to keep them both away.
19:11The first Androsarchus seizes its chance.
19:37After all day defending a lost cause,
19:39the mother appears to be giving up.
19:52The scavengers aren't used to having to share the spoils.
20:10As they wrestle for the calf,
20:11the mother mistakes its movement for signs of life.
20:19She is spurred into action again.
20:21She returns to her lonely and fruitless vigil.
20:33The Androsarchus will be back.
20:34She returns to her lonely and fruitless vigil.
20:46The Androsarchus will be back.
20:51As the weeks pass, the environmental crisis at sea shows no sign of easing.
21:09It can only be described as an ocean famine.
21:20For the female Bacillosaurus, who is now heavily pregnant, things are desperate.
21:25She is getting barely enough for herself to eat, never mind her unborn calf.
21:30With her limited fat reserves all but gone, her body will soon abort her offspring in order to preserve her own life.
21:37Suddenly, the sea around her is filled with the bustling activity of a group of smaller whales called Doradon.
21:53When Doradon gather in numbers, it means that the females are about to give birth.
22:07This might look like a friendly greeting.
22:09It is anything but.
22:12The smaller whales are mobbing the giant, using their numbers to try and force her away.
22:17Bacillosaurus preys on their young, and somewhere nearby must be the Doradon's carving ground.
22:23It appears as though she has been driven to the seabed, but there is method in her madness.
22:39She has to do something that is more important than ever if her unborn calf is to survive.
22:45She must scratch.
22:53By dragging herself over a convenient sandbar, she can slough off the outer layer of her skin, and with it, any parasites or barnacles that may have got a foothold.
23:05For an animal that relies on speed to hunt, keeping her body sleek and streamlined is the difference between success and hunger.
23:21She is ready to go hunting whales.
23:23Every year, Doradon gather in this calm, protected lagoon to give birth.
23:41The first calves are appearing, just a few days old.
23:48And already, in mortal danger, the Bacillosaurus has found the lagoon.
23:55She has been spotted, and the calves are quickly shepherded away from the threat.
24:05Defending together, the adult Doradon launch aggressive attacks against the Bacillosaurus in an attempt to drive her off.
24:26Their efforts appear surprisingly effective.
24:34The Bacillosaurus moves away.
24:43Calm is restored, but it won't last for long.
24:51This is a hungry mother.
24:53It's a hungry mother.
25:01Okay.
25:03Now I walk a little bun, but please open the grassと思
25:10If I land Theater.
25:16The Naughty mother died as a flower.
25:21Over the course of the next few days, the basilosaurus returns time after time.
25:28The lagoon is transformed from a sanctuary into a bloodbath.
25:39This is what it means to be top of the food chain.
25:46It has taken the death of several Dorodon calves to further the survival of the unborn basilosaurus.
26:16It has been a year since the female basilosaurus mated.
26:31She is once again out in the open seas.
26:37But this time, she is not alone.
26:48Against all the odds, she has finally given birth.
27:00Against the odds, she and her calf have survived.
27:12Sadly, what they have been through is merely the start of the climate chaos to follow,
27:17which will end the Eocene period and cause the largest extinction since the death of the dinosaurs.
27:26As devastating as any meteor will be the catastrophic disruption of the ocean's currents caused by the gradual freezing of Antarctica.
27:34Like a gigantic El Niño, only much, much worse, 20% of living things on Earth will die out.
27:44Whales as a group will survive.
27:47But Bacilosaurus and her kind will not be among them.
27:59Next time, mammals on land go from big to bigger.
28:03We will walk with the Indrocathias, mammals that rival in size the dinosaurs of old.
28:09It is a world of the big, the bad, and the ugly.
28:15Next time, mammals will never act.
28:17It is an enemy away.
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