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00:01Imagine if you could halt the constant march of time.
00:11If you could slow it down and speed it up.
00:17Imagine if you could stop time or even reverse it.
00:23The world about us would look quite different.
00:30Imagine no longer. Come with us as we go on a journey through time.
00:42Life is a race against the clock.
00:51For all of us, every second of every day, the pressure is on.
00:55To find food, meet a mate and have a family.
01:01All before our time is up.
01:04By speeding through days, months and years, we're going to see how plants and animals manipulate time to stay in the running.
01:20Why is it that a mouse lives for two years, while a whale can live for 200?
01:37Why do these crabs have their own little alarm clocks that must be reset every day?
01:46What drives these caribou to run thousands of kilometres through some of the harshest conditions on earth?
02:03And what has turned this hummingbird into the Pinocchio of the bird world?
02:08It's all down to time.
02:14By crushing centuries into seconds, we'll see life change beyond recognition and meet some real time travellers.
02:25But can anything truly cheat time and live forever?
02:38Different animals have different lifespans.
02:53Take a man and his dog.
02:55They both look like they could run and run.
02:58But one of them is already past his prime.
03:01The dog may look full of beans, but it's six years old.
03:07And in dog years, that means well into middle age.
03:12Dogs live to about 12, whereas we humans now expect to reach 80.
03:18Why do we have these hugely different lifespans?
03:24Even with these creature comforts, a house mouse will be lucky if it survives till it's two.
03:30Could lifespan be all down to size?
03:36Of course, a mouse only has to grow a tiny body.
03:41But that's not the whole story.
03:43Its short time on earth is also about staying one step ahead of danger.
04:00A mouse's life is so likely to come to a swift end that it pays to live life in the fast lane.
04:08A newborn mouse grows up at breakneck speed.
04:12Within a matter of days, the first hair erupts.
04:16Next, their body lengthens.
04:18The whiskers grow and the ears pop out.
04:28A baby mouse turns into an adult in just five weeks.
04:34Right away, it can start having babies of its own.
04:36In its short lifetime, a mouse can have several litters with up to 12 babies each time.
04:50You don't have to do the sums to see how mice can quickly take over the place.
04:55Individuals may not live very long, but their fast and furious way of life is a winning one if you're constantly dicing with death.
05:15A wild owl lives up to eight years.
05:26So what gives them the extra long lease?
05:35It's not just that they're bigger than mice.
05:38It takes a lot longer to bring up their brood.
05:41What took the mice five weeks takes the owls a whole year.
05:48By zooming through the months, we can see that an infant owl has to develop some pretty complicated kit to become a successful hunter.
05:59It needs a beak that can rip into prey.
06:04Special wing feathers that will help it glide silently through the night.
06:08Talons that can pincer a rodent.
06:13And discs of specialised feathers around each eye.
06:19Like satellite dishes, these focus the tiniest rustlings directly to its pin-sharp ears.
06:26Even when it's fully fledged, our young owl still needs time to learn the tricks of its hunting trade.
06:34Only then can it hope to find a mate and have a family of its own.
06:47It's a more demanding way of life, so they have to take things step by step.
06:52That's why barn owls live a lot longer than mice.
07:06But one animal has stretched its lifetime to an absolute extreme.
07:11Primitive harpoon heads have recently been found in a few bowhead whales.
07:28This proves that these whales can live for an incredible 200 years.
07:33Size matters, but living in the Arctic Ocean, it might take decades to fatten up and reach breeding age.
07:45But that's not the only delay. Over these frozen wastes, it can take ages to even find a partner.
08:02There is no speed dating here.
08:04In these tough waters, bowheads need very, very long lives to make sure there is a next generation.
08:17So what about us?
08:19Going by size, we humans should only live for 30 years.
08:24And in fact, most people have found partners and had a family by their 30s.
08:29But our lives don't stop there.
08:33Even though we might have done our bit to prolong the human race,
08:37we then expect to live way past our child-rearing years.
08:44Sociable animals, apes, dolphins and humans, get an extension on life.
08:51We've earned this extra time by becoming helpful in old age.
08:55Grandparents and other members of extended families offer wisdom, wealth and, of course, babysitting.
09:09Mouse, owl, whale or man, we've all got different lifespans which best suit how and where we live.
09:17But no matter how long or short our time on Earth, we're all under the thumb of one great clock.
09:25Great clock.
09:49As dawn breaks over Hong Kong, millions of people begin their journey to work.
09:53This mad rush hour may seem as far removed from nature as you can get.
10:03But in fact, we're not the only animal trapped in a nine-to-five routine.
10:12Off a remote island in the Pacific, golden jellyfish crowd a marine lake.
10:18By speeding up the clock, we can see that they too have a rush hour.
10:29Every day they rise at the same time and set off on the same commute across the lake.
10:35So why have they joined the rat race?
10:37The clue lies in their golden glow, a colour caused by millions of tiny algae that live within the jellyfish.
10:51The algae produce sugars which they share with their jellyfish partners.
10:58But to keep their golden complexion, the algae need a secret ingredient.
11:05Sunlight.
11:06Sunlight.
11:11That's where their mobile homes come in.
11:18The jellyfish transport the algae up towards the sun each morning.
11:23The water glistens as the jellies break the surface, but their job isn't over.
11:36All day they have to work the area of the lake, shifting position to follow the arcing sun.
11:41It's a long day, but it's the only way that both algae and jellies get enough to eat.
11:51The relationship is so successful that jellyfish numbers have boomed.
11:56Today there are over ten million of them.
11:59Unlike our jobs, there are no breaks.
12:06This is Round the Clock.
12:09Day in, day out.
12:29The setting sun triggers a return commute, back down to the depths of the lake.
12:42Just as we need rest and recuperation, the algae passengers must restock on vital nutrients that have sunk to the bottom.
12:51The algae get there on the jelly train.
12:59Tomorrow the whole thing will start again.
13:06The sun is boss.
13:09We and many other creatures clock on while the sun floods the world with heat and light.
13:17And clock off when it sinks from view.
13:20Its daily rhythm is our daily grind.
13:29It may feel relentless, but the big clock in the sky sets the pace at which our bodies work best.
13:43But it's not the only timepiece controlling life on Earth.
13:47Even though it is nearly 400,000 kilometers away, the moon also has a profound influence on many animals.
14:08As it spins around the Earth, it drags a great bulge of oceanic water in its wake.
14:14The rising tide.
14:20It ebbs and flows twice a day.
14:23But that's not all.
14:24Each day the timing of the new tide shifts forwards by nearly an hour.
14:30It's a highly complicated schedule, so how can anything live by it?
14:34It's two in the afternoon, and the incoming tide is driving waves towards the beach, to a surfer's paradise in Australia.
14:49The best surf is at the turn of the tide, but predicting when this is requires some precise astronomical calculations.
15:05Luckily, someone else has done the maths.
15:14All surfers need to do is check out the tide timetable, and then just watch the clock.
15:19Just watch the clock.
15:28That's it. Surf's up.
15:29That's it. Surf's up.
15:30That's it. Surf's up.
15:31Surf's up.
15:46Surf's up.
15:47¡Suscríbete al canal!
16:17Cloth being pulled back from over a hidden feast.
16:20The tiny creatures aren't exactly on a plate,
16:23but they are there for the taking.
16:30While the tide's out, it's dinner time.
16:33Not just for this one soldier crab, but a huge army of them.
16:47They're on a regimented march to the water's edge.
17:04With so many crabs to choose from,
17:06predators find it hard to single out their prey.
17:09The soldier crabs can only sieve out food along the shoreline
17:21while the sand is damp, so they haven't got long.
17:24Something extraordinary happens just before the tide turns.
17:39It's as if a sergeant major has barked out the order to retreat.
17:44As one, the crabs scuttle back up the beach.
17:48Just as well, if they were to stay out a moment too long,
18:00they would risk certain death.
18:04The incoming tide brings crab-hungry fish.
18:08Even though the tide times are constantly shifting,
18:16soldier crabs amazingly never get caught out.
18:19How do they get the timing right?
18:26Are they sensing movement under the sand?
18:31Is it down to remarkable eyesight?
18:37Or is something else going on?
18:45If we isolate crabs from the outside world,
18:48we can reveal the secret of their precision timing.
18:55Just watch what happens to these crabs
18:58as the tide rises and falls.
19:04When it's out, they run around, as if it's time to feed.
19:09But when it re-floods,
19:12they mysteriously stop moving,
19:14as they would if they were in their burrows.
19:18It's all down to an internal alarm clock
19:21that's tied not to the sun, but to the moon.
19:33What's more, it is incredibly sophisticated.
19:37It's self-adjusting.
19:38We wake up at more or less the same time each day.
19:41The crabs' wake-up call shifts by almost an hour with each tide.
19:54This is how the soldiers get their timing right.
19:57But it's not just animals that need to keep an eye on the clock.
20:16Many flowers open during daylight hours,
20:19but they don't all open at the same time.
20:25Take the morning glory.
20:27It opens soon after dawn,
20:30but the South African Miesem waits until noon.
20:34The evening primrose, as its name suggests,
20:37saves itself for the twilight hours.
20:39So what on earth is going on?
20:46Can plants really tell the time?
20:57When it comes to setting seed,
21:00flowers have a big problem.
21:02They must exchange pollen with each other.
21:05A bit tricky when you're rooted to the spot.
21:08Flowers need go-betweens,
21:15insects that can carry fertilising pollen
21:18from one flower to another.
21:21To attract the attention of passing insects,
21:24flowers have to flirt,
21:26and they do this with a dazzling array of colours and scents.
21:31But, of course, insects are being courted
21:34by every hot, blossomed flower in the bed,
21:37so some flowers have found a really cunning way
21:40of standing out in the crowd.
21:43And it's all down to timing.
21:45At sunrise, the morning glory is already on the pool,
21:55opening its petals before any other flower.
21:58This might seem risky, as few insects are up and about during these chilly hours.
22:05But the morning glory is counting on another early riser.
22:12Bumblebees are so big that they can warm up independently of the sun.
22:17They vibrate their wing muscles to generate their own internal heat
22:23and can get airborne as early as 5 a.m.
22:29Morning glories are ready and waiting.
22:32In return for spreading pollen,
22:39the bees are rewarded with a drink of nectar.
22:42The Mexican poppy takes a different approach.
22:52It's less fussy about who it flirts with,
22:55so it waits till after breakfast before giving its all.
22:59It's bright orange outfit is critical to its future.
23:05If rain or wind threaten,
23:07the poppy folds its petals away.
23:16By late morning, the flower bed is a riot of colour,
23:20a scramble of flowers trying to win the attentions of winged helpers.
23:25But the South African misem is only just opening.
23:28How can it afford this lazy start to the day?
23:34Its long line matches that of its chosen pollen, Kuria,
23:39an insect that needs a little more time to get going.
23:43Monkey beetles cannot take off
23:45until their body temperature reaches 27 degrees,
23:49so they're only out and about
23:51during the very hottest part of the day.
23:55On cue, the eye-catching misems are ready.
23:58On cue, the air-catching misems are ready.
24:04Oh, I love you.
24:07Oh, I love you.
24:10Oh, yes, I love you.
24:13Moi, non drus.
24:16Oh, non amour.
24:19Comme la vague.
24:20Pero tiempo es limitado.
24:23As soon as el temperatura empieza a descargar,
24:25las peatlas de descargar,
24:28así que los misens turnen off
24:30el charm, también.
24:37Una flor
24:38saves itself until
24:39after sundown,
24:41cuando más otras han ido a bed.
24:43Only then does el evening primrose
24:45waft its seductive
24:47scent over el jardín.
24:48It lures in night fliers
24:51such as moths.
24:55By waiting this late,
24:57the evening primrose
24:57has the pick of the insect
24:59night shift.
25:05So it seems plants
25:07really can tell the time.
25:09Right through the day,
25:10they keep appointments
25:11with their insect go-betweens.
25:13It's a highly efficient way
25:19of getting fertilised.
25:21So, importantly,
25:22it guarantees the next generation
25:25of floral timekeepers.
25:35Judging time over a day
25:37is one thing.
25:39But how about
25:40over months and years?
25:42Sometimes this is essential.
25:46Especially when it comes
25:47to keeping the whole
25:48family line on track.
25:50And for one North American animal,
25:57it's turned into a truly
25:59desperate struggle
26:00against the clock.
26:04It's high summer
26:06in northern Quebec
26:07and a huge herd
26:09of caribou
26:10covers the tundra.
26:12This is the richest
26:13pasture around.
26:14It's a perfect place
26:18to raise their young.
26:20But these caribou
26:21can't stay here.
26:23They are about
26:24to be driven away.
26:28But what's giving them
26:30the push?
26:32They live so far north
26:34that their world flips
26:36between seasonal extremes.
26:40It's June
26:41and these warm summer meadows
26:43are about to become
26:44howling snowscapes.
27:00As the autumn weather
27:02closes in,
27:03the caribou
27:04are forced
27:05to run south.
27:10It's the start
27:11of an incredible marathon.
27:14But there's a deadline.
27:15They need to get back
27:16to the summer meadows
27:18by June next year
27:19to give birth
27:20to their young.
27:23The further
27:24they go south,
27:25the more time
27:26it will take
27:27to get back.
27:28So they've got to keep
27:29one eye
27:29on the advancing weather
27:31and one
27:32on the clock.
27:33All the while
27:38their hormones
27:39are working
27:40to schedule.
27:41They flood
27:42through the males
27:43which kick-starts
27:44the rut.
27:50Antlers develop
27:51and harden
27:52in unison
27:53allowing the males
27:54to battle
27:55for females.
27:56The shorter day length
28:12has got female hormones
28:14racing too.
28:17It's no accident
28:18that males and females
28:20have their minds
28:21on the same thing.
28:22It's all part
28:24of the master plan
28:25to ensure
28:26that all the females
28:27get pregnant
28:28at the same time.
28:39Once that's done
28:40they're desperate
28:41to head back north
28:43back to their meadows
28:44but now the bad weather
28:46is blocking their way.
28:47For now
29:00they have to bide
29:01their time
29:02down here
29:02not a soft option
29:04so they scratch
29:06a living
29:06from lichens
29:07under the snow.
29:13It's a relentless
29:15search
29:16for the right diet.
29:17Lichens aren't enough
29:19for expectant mothers.
29:26Sometimes time
29:28just runs out.
29:36The females
29:37are now living
29:38close to the wire.
29:40The June deadline
29:41is getting closer.
29:43They're heavily pregnant
29:44but they're still
29:454,000 kilometres away
29:47from the rich
29:48summer meadows
29:49where they want
29:50to give birth.
29:56Even though the ground
29:57is still frozen
29:58alarm bells
29:59are ringing
30:00telling the females
30:01to head north again.
30:03they've been on their feet
30:11for months
30:11they've clocked up
30:129,000 kilometres
30:14all to make it back
30:16to the carving meadows
30:18in time.
30:19They arrive back
30:40just as these rich meadows
30:41come to their peak
30:42and that's the clever bit.
30:47Thousands of calves
30:48are born within days
30:50of each other
30:51and it's all been
30:52precision timed.
30:53That's because
30:54there's just
30:54a short window
30:55when the grass
30:56is at its best
30:57and when the calves
30:58can grow up quickly
30:59on their mother's
31:01fortified milk.
31:02They've met
31:06the deadline
31:07but time
31:08doesn't stand still.
31:13Within an hour
31:14of birth
31:15a calf
31:15is able to keep up
31:16with its mother
31:17and will soon be ready
31:18to join the caribou herd's
31:20annual marathon race
31:22against time.
31:29The natural rhythms
31:31of the earth
31:31hold animals
31:32in a vice-like grip.
31:34To survive
31:35they've simply
31:36got to keep up
31:36but some remarkable
31:38creatures have managed
31:40to step off
31:40this time treadmill.
31:44They've set
31:45their own agenda.
31:59It's the summer
32:01of 2003
32:02and the town of Elkin,
32:05North Carolina
32:05has been overwhelmed
32:07by a swarm
32:09of cicadas.
32:11Normally bird
32:12and mammal predators
32:13would be having
32:14a field day
32:15picking off
32:16these tasty morsels
32:17but strangely enough
32:19no one's eating them.
32:20It's as if the cicadas
32:21aren't really there.
32:24What's going on?
32:24These are periodic cicadas
32:28so-called
32:29because they've come up
32:30with an ingenious strategy
32:31to outwit
32:32their enemies.
32:33But to see it
32:35in action
32:35we have to go
32:36back in time
32:37half a century.
32:44It's 1952
32:46and the town of Elkin
32:47looks very different.
32:48The only familiar things
32:50are the cicadas.
32:54The residents of Elkin
32:56might have time
32:57on their hands
32:58but the adult cicadas
32:59have no time to lose.
33:02They only have
33:02three more weeks
33:03to complete
33:04their life cycle.
33:07First they must find
33:08a partner
33:08which they do
33:09with their own
33:10chirpy little number.
33:12Once they've mated
33:32the females lay
33:33all their eggs
33:34in the branches
33:35of trees.
33:42after they've hatched
33:43the larvae
33:43full to the ground
33:44and bury themselves.
33:46This in itself
33:48isn't unusual
33:49but what happens next
33:51is
33:51if we whiz through
33:54to the same time
33:55the following year
33:561953
33:56the fashions
33:58have moved on
33:59but the cicadas
34:00are nowhere to be seen.
34:02In fact
34:10we have to fast forward
34:1117 years
34:12to 1969
34:14before there is
34:15any sign of them again.
34:25While Neil Armstrong
34:26takes his first steps
34:28on the moon
34:28back on earth
34:30people are celebrating
34:31the summer of love.
34:51The cicadas
34:52have also emerged
34:53for their own
34:54summer loving.
35:01The world has moved on
35:10but the cicadas
35:11go through
35:11the same old routine.
35:13Once again
35:14the nymphs
35:14bury themselves
35:15and disappear
35:16from view
35:17but for how long
35:19will it be
35:19this time?
35:20In 1986
35:41exactly 17 years later
35:43they reappear.
35:45How on earth
35:53can the next generation
35:54buried deep underground
35:56measure the passing of time
35:58so accurately?
36:01It's now thought
36:02that the cicadas
36:03pick up cues
36:04from the yearly rise
36:06and fall of sap
36:07in plant roots.
36:09Yep,
36:09these guys
36:10are actually counting.
36:11It's only when
36:28they've counted
36:28another 17 years
36:30that these little
36:31time travellers
36:32appear again.
36:34We're back
36:34to where we started
36:35in 2003.
36:37But what's the reason
36:42for taking time
36:43out for so long?
36:46Well,
36:47since they show up
36:47so rarely
36:48no animal
36:49can rely on them
36:50as a source of food.
36:51In fact,
36:52most animals
36:52wouldn't even
36:53recognise them
36:54as food.
36:55They might have
36:56seen this sight
36:56only once
36:57in a lifetime.
37:06With little
37:06to threaten them
37:07the nymphs move
37:08into position
37:09for the last stage
37:10of their development.
37:12Here they can time travel
37:14and emerge
37:15into adulthood
37:16in peace.
37:17By morning,
37:40the whole town
37:41of Elkin
37:42is littered
37:43with their
37:44discarded
37:44nymphal shells.
37:50As long
37:51as they can
37:52accurately count
37:53up to 17
37:54and emerge
37:55altogether,
37:56they will
37:56outwit
37:57any potential
37:58predators.
38:02It's not just
38:03mathematically brilliant,
38:05it's biologically
38:06clever.
38:07Periodic cicadas
38:08have,
38:09quite literally,
38:10calculated how to
38:11stay out of other
38:12creatures' mouths
38:13and in the race
38:15against time.
38:19By time travelling
38:21through three generations
38:22of cicadas,
38:23we've unlocked the secret
38:25of their success.
38:27But just imagine
38:28if we could travel back
38:30through thousands
38:30of generations,
38:31what stories would unfold
38:34in front of our eyes.
38:37Horses haven't always
38:39been able to run
38:40this fast.
38:41They only became
38:42champion racers
38:43as they travelled
38:45through time.
38:45in front of our eyes.
38:54Galloping back
38:5550 million years,
38:57we'd find ourselves
38:57in a much hotter,
38:59wetter world.
39:01Lush rainforests
39:02blanketed the earth.
39:05This squat mammal
39:07was about as far
39:08from a sleek thoroughbred
39:10as you could get,
39:11but this is what the horse
39:13originally looked like.
39:14It was about the size
39:17of a domestic cat
39:19and with its delicate
39:20snout and teeth,
39:22it nibbled fruits
39:23and leaves
39:24on the forest floor.
39:28Its four-toed feet
39:29were designed
39:30for stability,
39:32not speed.
39:33It wouldn't be worth
39:34even a flutter
39:36at Ascot.
39:39It would have stayed
39:40a racing outsider,
39:42but for a dramatic change.
39:44in the earth's climate.
39:4740 million years ago,
39:50the world became
39:50cooler and drier.
39:53The ice caps grew.
39:57Their rainforest home
39:59died back
40:00and the early horse
40:01faced a very different future.
40:05The vast spaces left behind
40:06were filled by a new breed
40:08and a plant.
40:09A plant.
40:10Grass.
40:13Grass is tough stuff.
40:15To survive on it,
40:17you need big teeth
40:18and a strong jaw,
40:19which this delicate-mouthed animal
40:21would have to develop
40:23or else.
40:25The race was on.
40:28At first,
40:29only those with the strongest teeth
40:31lived long enough to breed,
40:33but if we speed through
40:34thousands of generations,
40:36we can see how the new grassy diet
40:39forced their teeth,
40:40head and jaw muscles
40:42to gradually become longer
40:44and stronger.
40:44A more familiar head
40:54was taking shape.
41:00But in other ways,
41:01they were still quite different
41:03from modern horses.
41:04For a start,
41:05they were still
41:06only the size of sheep.
41:07Even more critically,
41:11they still had
41:12those ancient toes,
41:13which made them
41:14very slow on their feet.
41:19On these exposed plains,
41:22wolf-like predators
41:23would have frequently
41:24had them on the run.
41:33They needed speed.
41:34Longer-legged animals
41:37were the ones
41:38that got away.
41:41So over yet more generations,
41:44these were the body parts
41:45that extended.
41:47At the same time,
41:48the toes disappeared,
41:50making the leg lighter
41:51and quicker
41:52to swing forward.
41:55The transformation
41:56from forest-dweller
41:58to flat-racer
41:59was complete.
42:04It took millions of years,
42:07but the horse
42:08came up with the goods.
42:10Generation by generation,
42:12it reworked itself
42:13into this odds-on favorite.
42:25Time forces change,
42:27but it can send
42:29some creatures down
42:30very odd routes indeed.
42:32Flying around
42:36with a beak this big
42:38is no joke.
42:41How did this poor hummingbird
42:43become the Pinocchio
42:45of the bird world?
42:51It's the humbling story
42:53of what happens
42:53when a bird
42:54is driven to drink.
42:56All hummingbirds' tipple
43:00of choice
43:01is sugar-rich nectar,
43:03but they have to work
43:04to get it,
43:06hovering in midair
43:07while shooting
43:08their long tongue
43:09down a flower.
43:12Just doing this
43:13uses up huge quantities
43:14of energy,
43:15so the more they drink,
43:17the more they need.
43:18They're addicted
43:19to the stuff.
43:19But it's the flowers
43:22that control the shots
43:24because they need the birds
43:25to distribute their pollen.
43:29As the birds
43:30are given a good drink
43:31of nectar,
43:32pollen rubs off
43:33onto the bird's forehead.
43:34As time moved on,
43:39certain flowers
43:40got increasingly picky
43:41about who came
43:42for a drink.
43:44Their flowers
43:44changed shape
43:45so that not all hummers
43:47could get in.
43:48It's like having
43:49a lock and key
43:50on the drinks cabinet.
43:52Only the birds
43:53with the right-shaped bill
43:54can get access.
44:01One bird
44:02tried to cheat
44:03the system.
44:04Thousands of years ago,
44:09swordbills
44:09with slightly longer beaks
44:11got an extra shot
44:13of nectar
44:13from the datura flower.
44:15But their heads
44:16were no longer
44:17in contact
44:18with the pollen,
44:19so the flower
44:20grew longer
44:21in response.
44:27Over generations,
44:29flower and beak
44:30tried to outsmart
44:32each other.
44:33Both became longer,
44:34and longer,
44:35increasingly dependent
44:37on each other.
44:41No other bird
44:42can reach the nectar
44:43from this outlandish flower,
44:45and the swordbills
44:47are stuck in a rut too.
44:50And that could be
44:52their undoing.
44:54For them,
44:55the future is now
44:56a one-way street,
44:58one that's more likely
44:59to be a dead-end.
45:03By speeding through
45:04thousands of generations,
45:05we've seen how
45:06hummingbirds and horses
45:08had to adapt.
45:10Time throws up surprises,
45:12and life just has to fit in.
45:13However, one animal
45:20has remained
45:21totally unruffled.
45:22It has cruised
45:24through 200 million years
45:26of Earth history
45:27without even breaking
45:28its stride.
45:32Other creatures
45:33were caught out
45:34by global cooling,
45:35global warming,
45:36or the Manhattan-sized
45:38meteor which caused
45:40one of the world's
45:41greatest mass extinctions.
45:42The cataclysm wiped out
46:07the dinosaurs,
46:09but this one animal
46:10was left untouched.
46:12The crocodile.
46:18What gave it the edge?
46:21The world went haywire,
46:23and dinosaurs
46:24were just too set
46:25in their ways.
46:27The croc had options.
46:29It survives in water
46:30as well as on land,
46:32and as fires raged
46:34across the planet,
46:35this was the safest
46:36place to be.
46:42It already had a gland
46:48which rids the body
46:49of salt,
46:50so it wasn't limited
46:51to fresh water either.
46:53It can stay under
46:54for three hours
46:56at a time,
46:57thanks to the clever
46:58design of its heart
47:00and lungs.
47:00This is how it kept
47:02out of trouble.
47:09But even a croc
47:11can't keep its head
47:12down forever.
47:13It emerged to a landscape
47:22of corpses,
47:23millions of them.
47:27Rotting flesh
47:28is a death trap
47:30of bacteria,
47:31so how did the crocodile
47:32find enough to eat?
47:34Well, it just tucked
47:39right in.
47:40It has a tougher
47:41than tough immune system,
47:43so it didn't matter
47:44that this meat
47:45was way past
47:46its sell-by date.
47:49What's more,
47:50it has powerful
47:51stomach juices,
47:52so even skin
47:53and bones
47:54can be digested.
47:56In those hard times,
47:58nothing went to waste.
48:04But there were
48:08other problems
48:09on the way.
48:10The Earth's atmosphere
48:11was clogging up
48:12with dust,
48:13soot and ash,
48:15plunging the planet
48:16into months
48:17of darkness.
48:21Even this
48:22didn't stop
48:23the crocodile
48:23in its tracks.
48:25It can see
48:26just as well
48:27in the dead
48:27of night
48:28and can sniff
48:29out rancid meat
48:30from over
48:31three kilometres
48:33away.
48:34It had all
48:38the right skills
48:39to stay
48:40in business.
48:49But the world
48:50was about
48:51to change
48:52again.
48:53As the atmosphere
48:54cleared,
48:55the sun rose
48:56on a very
48:57different world.
48:58The Earth
48:59was being taken
48:59over by warm-blooded
49:01creatures.
49:02Suddenly,
49:03the crocodile
49:03had some
49:04stiff competition.
49:06It might have
49:06proved itself
49:07during the Blitz.
49:08Was it any match
49:10for these new
49:10movers and shakers?
49:17The croc has yet
49:19another trick
49:19up its sleeve.
49:20Not only does it
49:21produce about 70
49:23babies at a time,
49:24but it actually
49:25looks after them.
49:26Most reptiles
49:27abandon their
49:28offspring,
49:29but this is
49:30a super mum
49:31who carefully
49:32watches over
49:33her hatchlings
49:33in a nursery
49:35lagoon.
49:43So many babies
49:44survive that
49:45the crocodile
49:46has never been
49:47in danger
49:48of dying out.
49:49while other animals
50:06have come and
50:07gone,
50:07the crocodile
50:08is still here,
50:10200 million years
50:12after it first
50:13appeared on the planet.
50:15What's more,
50:15it's survived
50:16completely unchanged.
50:18It hasn't needed
50:19to evolve.
50:20Unlike the horse,
50:21the crocodile
50:22had all the right
50:23stuff from the start.
50:32The crocodile family
50:34may have stood
50:35the test of time,
50:36but is this the best
50:37that life can do?
50:38Is it possible
50:40for any individual
50:41living thing
50:42to truly cheat
50:44time and live
50:45forever?
50:52We humans
50:54have done our best
50:55to extend
50:56our lifetimes.
50:58With family support
50:59and better health,
51:00we've added decades
51:02to our lifespan.
51:03But there is something
51:09that's taken
51:09almost magical control
51:11of its time
51:13on earth.
51:14To discover
51:15the secrets
51:15of its eternal life,
51:17we must remain
51:18in this English
51:19churchyard.
51:20But imagine
51:21travelling back
51:211,600 years
51:24to a funeral
51:30in the Dark Ages.
51:33It was a simple
51:35ceremony,
51:36but these early
51:37Christians were known
51:37to mark the grave
51:38by planting the sapling
51:40of a yew tree.
51:46Maybe our ancestors
51:48already had a hunch
51:49about the enduring
51:50nature of this tree.
52:00If we watch
52:01this yew sapling
52:02grow at speed,
52:04will its secrets
52:05be revealed?
52:08In its first 200 years,
52:10it witnesses
52:11the felling
52:11of most
52:12of the wildwood
52:13around.
52:15Perhaps because
52:16it marks
52:17a grave,
52:18our yew tree
52:19is spared.
52:21It's when it
52:22creeps into its
52:23third century
52:24that it starts
52:25to unveil
52:25mysterious powers.
52:26only the flesh
52:28of its berries
52:28is safe to eat.
52:30The leaves
52:31and bark
52:32are highly poisonous
52:33and are left
52:35well alone.
52:41The needles
52:42are like a curse.
52:45As they fall,
52:46their toxic juices
52:47leach out
52:48into the earth.
52:49It wipes out the competition
52:54so that the yew
52:55has all the goodness
52:56of the soil
52:57to itself.
52:59This is how it gives itself
53:01a head start.
53:02It might have stood out
53:11as monks
53:11were spreading
53:12the Christian faith
53:13across England
53:14because our 400-year-old yew
53:16had become
53:17a favoured burial site.
53:23A church
53:24is built
53:25on this sacred ground.
53:26As the centuries
53:33pass,
53:34the church
53:34increases
53:35in stature.
53:39Meanwhile,
53:40the yew tree
53:41seems master
53:42of its own destiny.
53:43It doesn't just
53:44grow slowly.
53:45It appears
53:46to be able
53:46to stop itself
53:47growing altogether.
53:55These are tricks
53:56which our tree
53:57will need
53:57because as we
53:59roll into
53:59the Middle Ages
54:00there's trouble
54:01in store.
54:06The weather
54:07is at its worst.
54:09The winters
54:09are long
54:10and cold
54:10and it rains
54:11cats and dogs.
54:24Many of its neighbours
54:25are toppled
54:26by strong gales
54:27but the yew
54:28stands firm.
54:31During its slow,
54:32slow growth
54:33it's laid down
54:34hard,
54:35close-grained wood
54:36and that gives
54:37its trunk
54:38and branches
54:38immense strength
54:40and flexibility.
54:45It weathers
54:46the Middle Ages
54:47but at 1,200 years old
54:49disaster
54:50is about to strike
54:52big time.
54:53While cavaliers
55:02and roundheads
55:03are tearing
55:03the country apart
55:04the yew tree
55:05has its own
55:06battle to fight.
55:08The dense wood
55:08which served it
55:09so well
55:10has trapped pools
55:11of water
55:12between the branches.
55:14The very heart
55:15of the tree
55:16is beginning
55:16to rot.
55:18Surely
55:18this is the end.
55:24But at what
55:25seems like
55:26its final hour
55:27it conjures up
55:28its most
55:29remarkable trick
55:30of all.
55:32The tree
55:33throws itself
55:34a lifeline.
55:38A young branch
55:39from the canopy
55:40does a U-turn
55:41and grows downwards
55:43right down
55:44into the rotting wood.
55:50There it feeds
55:51off its own
55:52compost.
55:53It has turned
55:53itself into
55:54a new root.
56:00It digs down
56:02through the heart
56:02wood into the
56:03ground
56:04replanting itself.
56:06This is a tree
56:07that has the power
56:09to be born
56:10again
56:10and again.
56:15Rejuvenated
56:16the tree
56:17marches steadily
56:18on
56:18into the
56:1921st century.
56:21It's now
56:211600 years old
56:23and still
56:24going strong.
56:29These days
56:31it often
56:31stands
56:32over a wedding.
56:33We have
56:34all
56:35the time
56:38in the world
56:41just for love
56:44nothing more
56:46nothing less
56:49on
56:51love
56:52this U- has
57:03already outlived
57:0480 generations
57:06of people
57:06but who knows
57:07how much further
57:08through time
57:09it might travel.
57:22This ancient tree
57:24seems to know
57:25nothing of old
57:26age
57:27or death.
57:28It appears
57:29to have found
57:29life's holy grail
57:31the ultimate
57:32time-busting
57:33strategy
57:34the ability
57:35to live forever.
57:36but the U- tree
57:48is not
57:48the only
57:49winner
57:49over time
57:52individuals
57:52may come
57:53and go
57:53entire species
57:55may adapt
57:56or die
57:57but life
57:58itself
57:58in all
57:59its different
58:00forms
58:00has been
58:01steadily
58:02marching
58:03through time
58:04so far
58:05for an
58:06incredible
58:06three and a
58:07half
58:07billion years.
58:11That's
58:11staying power
58:12and that's
58:14what matters
58:14most
58:15in life's
58:16race
58:16against time.
58:21Next week
58:22we discover
58:23why we are
58:24so obsessed
58:24with mastering
58:26time
58:26why our lives
58:28are ruled
58:29by clocks
58:30we never see
58:30and what we are
58:32doing that could
58:33let us live
58:33forever.
58:35we see
58:35what our
58:36ever-increasing
58:36pace of life
58:37is doing
58:38to the world
58:39we live in
58:40and how our
58:41need for speed
58:42may one day
58:43let us all
58:44travel through
58:45time.
58:45we see
58:57we see
58:58we see
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