0:00:02 > 0:00:03In the vastness of the Pacific,
0:00:03 > 0:00:06a once-in-a-lifetime expedition is underway.
0:00:08 > 0:00:09For the next few weeks,
0:00:09 > 0:00:12we are going on a voyage of discovery
0:00:12 > 0:00:17covering over 1,000km through the Galapagos Islands.
0:00:17 > 0:00:21Galapagos, one of the treasures of the natural world.
0:00:26 > 0:00:31Over 1,000 species here are found nowhere else on earth,
0:00:31 > 0:00:33and they've evolved in extraordinary ways.
0:00:36 > 0:00:39But this paradise is under threat,
0:00:39 > 0:00:42as our world is changing like never before.
0:00:46 > 0:00:49Now we're embarking on one of the most ambitious
0:00:49 > 0:00:53scientific expeditions ever attempted in Galapagos.
0:00:54 > 0:00:58I'm Liz Bonnin, I'm a wild animal biologist helping to carry out
0:00:58 > 0:01:01ground-breaking research in the field.
0:01:04 > 0:01:07Joining me is a team of world-renowned scientists.
0:01:09 > 0:01:11Equipped with cutting-edge technology,
0:01:11 > 0:01:15we'll be able to study the wildlife of Galapagos up close
0:01:15 > 0:01:17to see how it's adapting to change.
0:01:18 > 0:01:21- How does that look? - That's perfect.
0:01:21 > 0:01:23'In its rich ocean.'
0:01:23 > 0:01:24Orca pod just sighted.
0:01:24 > 0:01:26There, right there.
0:01:26 > 0:01:28'On its volcanic slopes.'
0:01:28 > 0:01:31This volcano erupted this time last year.
0:01:32 > 0:01:34'And within hidden worlds.'
0:01:34 > 0:01:38This place is just incredible.
0:01:40 > 0:01:44We'll attempt to help save animals on the brink of extinction.
0:01:44 > 0:01:46Iguana! Iguana!
0:01:48 > 0:01:53And dive into the unknown to discover species new to science.
0:01:56 > 0:01:59This just changes everything.
0:01:59 > 0:02:01Everything.
0:02:01 > 0:02:03Oh, my God, look at this.
0:02:06 > 0:02:08This is Mission Galapagos.
0:02:34 > 0:02:38Combined, the Galapagos Islands cover an area just a tenth
0:02:38 > 0:02:39the size of Scotland.
0:02:44 > 0:02:46They lie in the Pacific,
0:02:46 > 0:02:491,000km from the coast of South America.
0:02:51 > 0:02:54Galapagos is made up of 13 main islands
0:02:54 > 0:02:56and many smaller rocky outcrops.
0:03:02 > 0:03:04Sitting right on the equator,
0:03:04 > 0:03:08these subtropical islands enjoy relatively consistent temperatures.
0:03:11 > 0:03:14But this also makes them vulnerable to the rapid effects
0:03:14 > 0:03:16of climate change.
0:03:18 > 0:03:20And now these unique islands
0:03:20 > 0:03:23are under greater threat than ever before.
0:03:23 > 0:03:27It's why we've come here to study their animals and find ways
0:03:27 > 0:03:28to protect them.
0:03:31 > 0:03:37This is Alucia, a 56-metre research vessel - our base of operations.
0:03:39 > 0:03:44An expedition like this on this sort of scale has never been attempted
0:03:44 > 0:03:45in the Galapagos before.
0:03:45 > 0:03:49Over the next few weeks, we'll be gaining unprecedented insights
0:03:49 > 0:03:52into the wildlife here, with the help of the scientists
0:03:52 > 0:03:53we're teaming up with.
0:03:53 > 0:03:57This ship is a scientist's dream.
0:03:57 > 0:03:59INDISTINCT RADIO COMMUNICATION
0:04:00 > 0:04:03'And we'll be working alongside some of the best from both
0:04:03 > 0:04:06'the Galapagos and across the world,
0:04:06 > 0:04:10'all taking advantage of this unique opportunity.'
0:04:13 > 0:04:17Charles Darwin visited the Galapagos almost 200 years ago
0:04:17 > 0:04:19on a research expedition of his own.
0:04:19 > 0:04:22He was just 26 years old at the time.
0:04:23 > 0:04:27He began to recognise the process of evolution here,
0:04:27 > 0:04:30which would inspire a theory that transformed the way we think
0:04:30 > 0:04:32about all life on Earth.
0:04:37 > 0:04:41On the first leg of this journey we'll be exploring the youngest
0:04:41 > 0:04:44volcanic islands in the west of the Galapagos and investigating
0:04:44 > 0:04:47the remarkable ways in which animals have adapted
0:04:47 > 0:04:50to their hostile environments.
0:04:52 > 0:04:55We'll be looking for the species that are most at risk,
0:04:55 > 0:04:58to find out if they're adapting fast enough to survive.
0:05:05 > 0:05:09Our first mission will be one of the most ambitious of all.
0:05:10 > 0:05:14It will take us to the very top of the active Wolf Volcano.
0:05:16 > 0:05:19In this extreme location, we'll be looking
0:05:19 > 0:05:22for one of the most recently discovered and rarest species.
0:05:27 > 0:05:30Weather conditions around the volcano are so changeable
0:05:30 > 0:05:34that, if we get it wrong, we'll be stranded.
0:05:34 > 0:05:38Our helicopter pilot, Tyler, isn't taking any chances.
0:05:38 > 0:05:41Something that we take very seriously is getting someone
0:05:41 > 0:05:44up there and then not being able to pull them back off the mountain
0:05:44 > 0:05:46for potentially days,
0:05:46 > 0:05:50and, so, we've briefed the team to bring shelter,
0:05:50 > 0:05:54bring enough food to last a day or two just in case the weather
0:05:54 > 0:05:56moves in and we can't get back to you.
0:06:12 > 0:06:14- PILOT:- We're currently at a course of 000,
0:06:14 > 0:06:17speed 11 knots through the water.
0:06:20 > 0:06:24The volcano towers over the northern part of Isabela,
0:06:24 > 0:06:27the largest island in Galapagos.
0:06:27 > 0:06:32Wolf is one of six volcanoes which erupted and joined together
0:06:32 > 0:06:35to form this island over the past million years.
0:06:39 > 0:06:41Seeing it for the first time is breathtaking.
0:06:51 > 0:06:54There it is, Wolf Volcano.
0:06:55 > 0:06:57Sitting above the clouds.
0:06:57 > 0:07:03It's the tallest volcano in the Galapagos - 1,700 metres.
0:07:05 > 0:07:08It's one of the least explored, most pristine parts
0:07:08 > 0:07:11of the archipelago, and it's home to a reptile
0:07:11 > 0:07:15that only a few people have ever seen in the flesh -
0:07:15 > 0:07:16the pink iguana.
0:07:20 > 0:07:24It wasn't until 2009 that the pink iguana was first identified
0:07:24 > 0:07:29as a new species, and scientists think that only around 200 remain.
0:07:33 > 0:07:37It's thought they once lived all across the Galapagos Islands,
0:07:37 > 0:07:39but, slowly, this species has been dying out.
0:07:41 > 0:07:44It's hard to believe that Wolf Volcano is now the only place
0:07:44 > 0:07:46on Earth that they exist.
0:07:48 > 0:07:52And, up here, everything can change in the blink of an eye.
0:07:55 > 0:08:00All of this lava flow is very, very young.
0:08:00 > 0:08:04This volcano erupted this time last year.
0:08:04 > 0:08:07We are camping on the other side,
0:08:07 > 0:08:11which I'm told is the inactive side of a volcano.
0:08:11 > 0:08:13But, like all good volcanoes,
0:08:13 > 0:08:18you don't ever know exactly where or when it's going to erupt next.
0:08:22 > 0:08:27The 2015 eruption shook the scientific community.
0:08:27 > 0:08:30Over half the volcano's crater was covered in lava,
0:08:30 > 0:08:33wiping out every living thing in its path.
0:08:38 > 0:08:42So, assessing how many pink iguanas are left is vital.
0:08:42 > 0:08:44But, first, we have to find them.
0:08:46 > 0:08:49A few days ago, our team of scientists headed up in advance
0:08:49 > 0:08:51to drop off equipment and set up camp.
0:08:53 > 0:08:54Now I'm joining them.
0:08:57 > 0:09:01Evolutionary biologist and team leader Dr Gabriele Gentile
0:09:01 > 0:09:02is here to meet me.
0:09:02 > 0:09:06- Gabriele!- Hello, Liz.- How are you?
0:09:06 > 0:09:07I'm pretty good, how about you?
0:09:07 > 0:09:10Really well. What a flight in. That was extraordinary.
0:09:10 > 0:09:12- Welcome here. - How are things in camp?
0:09:12 > 0:09:15- Good.- Shall we get some coffee going?- Let's get some coffee.
0:09:17 > 0:09:19Hola, everybody.
0:09:19 > 0:09:20Hello, hello, hello.
0:09:20 > 0:09:26'Gabriele and his team identified the pink iguana as a new species.
0:09:26 > 0:09:28'So, if anybody can find one, it's them.'
0:09:30 > 0:09:32This is what we'll be doing today. We'll start from the camp,
0:09:32 > 0:09:35then we'll walk along the rim of the crater.
0:09:35 > 0:09:39We have to proceed very slowly and try not to be very loud
0:09:39 > 0:09:41cos iguanas, they'll run away.
0:09:41 > 0:09:46Very important is that any of us that will see an iguana just say,
0:09:46 > 0:09:50"Hey, iguana," and we'll start our procedure to capture them
0:09:50 > 0:09:52and then collecting data.
0:09:52 > 0:09:53- Bueno?- Bueno.
0:09:53 > 0:09:55Good, good, good. Can I have an almond?
0:09:55 > 0:09:56No.
0:09:56 > 0:09:58LAUGHTER
0:10:05 > 0:10:09Understanding as much as possible about the pink iguana,
0:10:09 > 0:10:12how they live, what they eat, when they breed,
0:10:12 > 0:10:16is the only way for scientists to learn how to protect them.
0:10:18 > 0:10:20The search is on.
0:10:43 > 0:10:47This is mind-blowing, Gabriele.
0:10:47 > 0:10:51- Yeah, it's beautiful.- I know we're on a mission but can I just
0:10:51 > 0:10:54take two seconds? I need to take this in.
0:10:54 > 0:10:56- Take your time.- Wow.
0:11:30 > 0:11:33It's not long before we spot the first clues -
0:11:33 > 0:11:37the burrows these reptiles use for nesting and shelter.
0:11:37 > 0:11:38Big hole over here.
0:11:39 > 0:11:41Burrows everywhere.
0:11:41 > 0:11:44We have to be really careful not to stand near the burrow
0:11:44 > 0:11:47otherwise we'll just collapse the whole thing.
0:11:47 > 0:11:49They're quite delicate.
0:11:50 > 0:11:53There's another one. Just be really careful.
0:12:09 > 0:12:11After hiking for hours,
0:12:11 > 0:12:16it's becoming clear that finding a pink iguana really isn't that easy.
0:12:26 > 0:12:29Look at the size of Wolf Volcano.
0:12:29 > 0:12:35And there are about 200 pink iguanas that scientists need to find
0:12:35 > 0:12:36in order to protect them.
0:12:47 > 0:12:48Iguana!
0:12:49 > 0:12:50Iguana!
0:12:55 > 0:12:57We've got a pink iguana. It's a new one.
0:12:59 > 0:13:02- It's big.- It is. It's a big male.
0:13:02 > 0:13:04Oh, my God.
0:13:04 > 0:13:05It's a huge male.
0:13:07 > 0:13:08- Look at that.- All right.
0:13:09 > 0:13:11Well done.
0:13:11 > 0:13:13It's a big one.
0:13:21 > 0:13:23He is such a beautiful specimen.
0:13:23 > 0:13:25He looks really healthy.
0:13:25 > 0:13:26He actually is in good shape.
0:13:28 > 0:13:32There's not much food now in this area
0:13:32 > 0:13:34- but he's doing good.- Yeah.
0:13:34 > 0:13:36Once found across the island chain,
0:13:36 > 0:13:40over thousands of years and due in part to competition from
0:13:40 > 0:13:44another iguana species, Wolf has become their last stronghold.
0:13:44 > 0:13:47- So, Gabriele, I presume you have to work really quickly.- Yeah.
0:13:50 > 0:13:5171.
0:13:52 > 0:13:55HE SPEAKS IN SPANISH
0:13:55 > 0:13:56So, now we measure this animal.
0:13:57 > 0:14:00Measuring size and weight will indicate if it's getting
0:14:00 > 0:14:05enough food and growing normally. Blood tests will show hormone levels
0:14:05 > 0:14:07and any signs of disease.
0:14:07 > 0:14:11This data will tell the team if the last remaining pink iguanas
0:14:11 > 0:14:12are healthy.
0:14:13 > 0:14:15To set eyes on a pink iguana...
0:14:17 > 0:14:19..is an honour, actually.
0:14:19 > 0:14:22It's a real honour. And he's beautiful.
0:14:22 > 0:14:24He's a stunning male.
0:14:24 > 0:14:25Look at that.
0:14:27 > 0:14:31This colour is not due to the presence of pigment but is actually
0:14:31 > 0:14:33blood flowing in the deeper layer of the skin.
0:14:33 > 0:14:35So they're pink but not because of pink pigment.
0:14:35 > 0:14:37They're pink because they have no pigmentation.
0:14:37 > 0:14:39That's correct.
0:14:39 > 0:14:42Given the fact that you're taking so many measurements
0:14:42 > 0:14:43from this individual alone,
0:14:43 > 0:14:46is that indicative of how little we know about pink iguanas?
0:14:46 > 0:14:49Well, we collect all the data because they may be informative
0:14:49 > 0:14:52about the ecology and evolution of the species,
0:14:52 > 0:14:55because there are so few individuals left.
0:14:56 > 0:15:00Scientists still don't fully understand why so few pink iguanas
0:15:00 > 0:15:04survive, and whether this tiny population can ever recover.
0:15:04 > 0:15:08But this research will go a long way towards gaining more knowledge
0:15:08 > 0:15:09about this precious reptile.
0:15:11 > 0:15:13So, there we go. He's marked him on his body.
0:15:15 > 0:15:16The paint is harmless,
0:15:16 > 0:15:20but will allow Gabriele to identify this animal.
0:15:20 > 0:15:21Are we letting him go now?
0:15:21 > 0:15:23- Yeah, we're letting him go. - And to think that they're...
0:15:25 > 0:15:27..just hanging on by a thread.
0:15:27 > 0:15:31I love the fact that it was done quickly, calmly,
0:15:31 > 0:15:33minimum stress to the animal,
0:15:33 > 0:15:36get your measurements done and then off you go.
0:15:36 > 0:15:40Gabriele can use the data he's gathered to explore a new plan,
0:15:40 > 0:15:44to move some of the iguanas to another part of Galapagos
0:15:44 > 0:15:47and establish a second healthy population.
0:15:47 > 0:15:50There will be chances for this species to survive,
0:15:50 > 0:15:52especially continuing to input all these efforts.
0:15:52 > 0:15:55To give the pink iguana a chance somewhere else.
0:15:55 > 0:15:56Another spot to live.
0:15:56 > 0:15:58But for this to have success,
0:15:58 > 0:16:02we need to learn a lot about the ecology of the species.
0:16:02 > 0:16:04There are so few left in just this one place.
0:16:04 > 0:16:06Are we watching it on its way out,
0:16:06 > 0:16:09as part of the natural process of evolution?
0:16:09 > 0:16:12So, we have to consider extinction like a natural process as well,
0:16:12 > 0:16:14but what a loss would that be.
0:16:29 > 0:16:30Dinner time.
0:16:38 > 0:16:40Chicken soup.
0:16:40 > 0:16:42Thank you. Gracias.
0:16:43 > 0:16:45Oh, yum.
0:16:45 > 0:16:47Really, really good day.
0:16:48 > 0:16:52It's just amazing to be out in nature like this.
0:16:52 > 0:16:54You feel really alive.
0:16:59 > 0:17:02The story of how the pink iguana ended up
0:17:02 > 0:17:06on a remote volcano on the equator,
0:17:06 > 0:17:11and somehow managed to make it here is ultimately a story of survival.
0:17:11 > 0:17:14And stories like these abound here.
0:17:14 > 0:17:19They're what make the Galapagos such a unique and special place.
0:17:37 > 0:17:40Next morning, I head back to the Alucia,
0:17:40 > 0:17:43leaving Gabriele and his team to search for more pink iguanas
0:17:43 > 0:17:45during their final days here.
0:17:52 > 0:17:56From a recently-discovered species at the top of a volcano,
0:17:56 > 0:18:00it's time for me to descend down the side of one,
0:18:00 > 0:18:02in search of new species on the sea floor.
0:18:07 > 0:18:11'A mission that's only possible thanks to Alucia's most impressive
0:18:11 > 0:18:13'pieces of technology.'
0:18:13 > 0:18:15Two deep sea submersibles,
0:18:15 > 0:18:20each capable of descending 1km beneath the waves.
0:18:23 > 0:18:26'Leading this search is our expedition's marine biologist,
0:18:26 > 0:18:29'Dr Pelayo Salinas de Leon.'
0:18:29 > 0:18:31We're very excited about this dive.
0:18:31 > 0:18:34It's the first time I'll be down to 1,000 metres.
0:18:34 > 0:18:39And we're basically collecting as many weird-looking,
0:18:39 > 0:18:42odd creatures that we encounter.
0:18:42 > 0:18:45Pretty much everything that we see is very likely to be a new species
0:18:45 > 0:18:46to science.
0:18:50 > 0:18:54Our mission is taking us to a place no-one has gone before.
0:18:57 > 0:19:01And we're in the safe hands of our submersible pilot Buck Taylor,
0:19:01 > 0:19:05a veteran with over 2,000 dives under his belt.
0:19:05 > 0:19:07It's such a harsh environment.
0:19:07 > 0:19:10We're down at 1,000 metres, 3,300 feet.
0:19:10 > 0:19:13Everything wants to crush us.
0:19:13 > 0:19:16The pressure outside is huge.
0:19:16 > 0:19:20So we've got to make sure every single system on the sub is working,
0:19:20 > 0:19:22and working perfectly before we go anywhere near the water.
0:19:24 > 0:19:25Come to starboard.
0:19:27 > 0:19:28Come to port.
0:19:30 > 0:19:33It's time for a final briefing in mission control.
0:19:38 > 0:19:41Alucia's technical officer, Victor,
0:19:41 > 0:19:45has been busy scanning the sea floor here to create 3-D maps of the area
0:19:45 > 0:19:47we're hoping to explore.
0:19:49 > 0:19:52So, how deep is it at its deepest point?
0:19:53 > 0:19:58The area that we actually scanned is 1,550 metres.
0:19:58 > 0:20:01OK. So, obviously, depth is important but then there's more
0:20:01 > 0:20:05to it than just going deep, isn't there? What are we looking for?
0:20:05 > 0:20:09We'll be looking at the green, which is around 1,000 metres.
0:20:09 > 0:20:12And we'll be looking at this sort of shape.
0:20:12 > 0:20:15So, the craggy bits, not the smooth slopes.
0:20:15 > 0:20:19- Why?- Because the craggy means very steep.
0:20:19 > 0:20:23That's the perfect environment for animals to grow.
0:20:23 > 0:20:26So, all these ridges are prime real estate.
0:20:26 > 0:20:29So, that's what we're looking for - all the critters on the edge.
0:20:29 > 0:20:32But does it make it more difficult to get to those areas?
0:20:32 > 0:20:33Yes, sometimes.
0:20:33 > 0:20:35We've got to approach with caution.
0:20:36 > 0:20:37It could all change, you know.
0:20:37 > 0:20:39Overhangs, ridges,
0:20:39 > 0:20:43gullies and we get these local little anomalies with currents
0:20:43 > 0:20:46and things, where it'll start rushing over an edge.
0:20:46 > 0:20:51So, it'll start pushing the sub around, and it keeps us on our toes.
0:20:51 > 0:20:55OK. You say the whole thing with a massive grin on your face.
0:20:55 > 0:20:58- Cos it's fun.- It's not a nervous grin, is it?
0:20:58 > 0:20:59- No.- OK.
0:21:01 > 0:21:06I'm with Buck and Pelayo in the yellow three-seater sub, Nadir.
0:21:06 > 0:21:11The smaller Deep Rover is our support sub, piloted by Toby.
0:21:14 > 0:21:18Deep Rover will collect the samples for us and, at 1,000 metres,
0:21:18 > 0:21:20is also an essential safety sub.
0:21:26 > 0:21:29- Welcome to Nadir.- Thank you.
0:21:29 > 0:21:31INDISTINCT RADIO COMMUNICATION
0:21:33 > 0:21:37Nadir, safety brief complete, ready to charge.
0:21:37 > 0:21:38Roger. Shut your hatches.
0:21:38 > 0:21:41- Both happy?- Yeah, really happy.
0:21:41 > 0:21:44- 'As soon as they're ready.' - Understood.
0:21:46 > 0:21:49OK, moving off down the trolley.
0:21:49 > 0:21:51All of Alucia's crew are now focused
0:21:51 > 0:21:55on getting our eight-tonne submersible safely on its way.
0:21:56 > 0:21:57- Wow.- Here we go.
0:21:57 > 0:22:001,000 metres underneath us.
0:22:00 > 0:22:02- Piece of cake.- Piece of cake.
0:22:02 > 0:22:03What's this for? For when I cry?
0:22:03 > 0:22:05Yes.
0:22:08 > 0:22:09OK. Bring it up.
0:22:13 > 0:22:15That's the Nadir off-deck.
0:22:37 > 0:22:38Nadir, ready to go.
0:22:38 > 0:22:39Roger.
0:22:56 > 0:22:57Bye-bye, surface.
0:23:07 > 0:23:10In the Alucia's mission control room, surface officer, Alan,
0:23:10 > 0:23:14will be tracking our progress every step of the way.
0:23:14 > 0:23:17We've had a really successful launch.
0:23:17 > 0:23:20At the moment, we can track them on sonar and we get very,
0:23:20 > 0:23:21very good comms.
0:23:21 > 0:23:24They've just reported in. Conditions are good.
0:23:24 > 0:23:25VOICE FROM NADIR
0:23:25 > 0:23:28As you can hear, they're talking between themselves.
0:23:32 > 0:23:35So, we basically free-fall into the depths.
0:23:37 > 0:23:39What speed are we descending at?
0:23:39 > 0:23:41We try and do about one metre every four seconds.
0:23:46 > 0:23:51At 200 metres, the light begins to disappear.
0:23:51 > 0:23:54Below us is over 1,000 metres of deep sea.
0:23:56 > 0:23:59This is the biggest ecosystem on earth.
0:23:59 > 0:24:02It's also the most unexplored.
0:24:06 > 0:24:11Control, control, Nadir passing 250 metres, over.
0:24:11 > 0:24:13I feel like I'm in space.
0:24:13 > 0:24:16It's better than space because there is life here.
0:24:16 > 0:24:21It's sad that we do know more about the moon than we know about this.
0:24:21 > 0:24:24And there's going to be critters going extinct that we've never
0:24:24 > 0:24:26even discovered yet.
0:24:32 > 0:24:35'We descend through clouds of zooplankton.
0:24:35 > 0:24:40'Many of these tiny animals are invisible to the naked eye,
0:24:40 > 0:24:42'but they're the lifeblood of these oceans.'
0:24:44 > 0:24:48Just this is really breathtaking.
0:24:48 > 0:24:52Because this is the reason why everything in the Galapagos
0:24:52 > 0:24:55is so biodiverse and thriving.
0:24:55 > 0:24:57It's all to do with this.
0:24:57 > 0:25:02This soupy mix of all sorts of strange-shaped organisms.
0:25:08 > 0:25:11'Zooplankton feeds a huge variety of sea life,
0:25:11 > 0:25:14'and kick-starts the entire marine food web.'
0:25:17 > 0:25:20You know, you're on the surface looking at all these charismatic,
0:25:20 > 0:25:24big, beautiful animals but actually this is more awe-inspiring
0:25:24 > 0:25:25and actually more humbling, in a way.
0:25:25 > 0:25:29- Yes.- If it wasn't for this, none of it would exist.
0:25:32 > 0:25:34'We head towards our target depth.
0:25:36 > 0:25:40'It's pitch-black down here and we're reliant on assistance
0:25:40 > 0:25:41'from the surface.
0:25:41 > 0:25:43'Nearing the jagged rocks,
0:25:43 > 0:25:46'this can be the most dangerous stage of the dive.'
0:25:48 > 0:25:51Nadir, Nadir, this is control, over.
0:25:51 > 0:25:54As you can see, the subs are here at the moment, both together.
0:25:54 > 0:26:00That area between the 50 metre, 80 metre and getting to 150 metres
0:26:00 > 0:26:02off the bottom, we have to guide them.
0:26:05 > 0:26:08'Until we can see the rocks, we're in their hands.
0:26:19 > 0:26:23'Then, from out of the darkness, the flank of the volcano appears.'
0:26:29 > 0:26:30Wow.
0:26:35 > 0:26:36What is all this stuff?
0:26:38 > 0:26:40Are they corals?
0:26:40 > 0:26:42Control, control, Nadir.
0:26:44 > 0:26:48Visibility lights on. 15 metres. Lights off, zero.
0:26:48 > 0:26:52Bottom composition - rock and some sediment.
0:26:54 > 0:26:56Tidal stream, we've got a slight...
0:27:03 > 0:27:07'Two hours into the dive, we reach our target depth.'
0:27:11 > 0:27:121,000 metres, everybody.
0:27:15 > 0:27:18So, there's five of us down here in the subs,
0:27:18 > 0:27:21and there's only five people ever seen this. Ever.
0:27:25 > 0:27:29'This is the deepest anyone has ever been in the Galapagos Islands.'
0:27:34 > 0:27:37Just as we looked up at the screen, we knew they were close.
0:27:39 > 0:27:42They are at 1,000 metres. So they're not interested in telling us,
0:27:42 > 0:27:45or anything like that, they're just getting on with the job.
0:27:45 > 0:27:49'Control, Nadir, depth 1,000 metres with the Rover.
0:27:49 > 0:27:52- 'Over.'- As we hear, they've thought about us now,
0:27:52 > 0:27:54and they've told us that they're 1,000 metres, you know.
0:27:54 > 0:27:58So, that's nice that we know they're safe, they're happy.
0:28:07 > 0:28:10How does it feel to be our modern-day, deep-sea Darwin?
0:28:12 > 0:28:14- A lot of pressure? - It's a lot of pressure,
0:28:14 > 0:28:16but I prepared all my life for this.
0:28:16 > 0:28:18I love it. I love it.
0:28:19 > 0:28:22Over a kilometre beneath the waves,
0:28:22 > 0:28:27the mission is now to ascend up the volcano wall to find and collect
0:28:27 > 0:28:28new species.
0:28:32 > 0:28:34This is basically the flank of a volcano.
0:28:34 > 0:28:35Yes.
0:28:36 > 0:28:38We're climbing a volcano.
0:28:45 > 0:28:48Soon, a remarkable fish decides to pay us a visit.
0:28:55 > 0:28:59A Galapagos ghost shark, or chimaera.
0:28:59 > 0:29:01Oh, my God, he's awesome.
0:29:02 > 0:29:06A fish discovered relatively recently, but it's been around
0:29:06 > 0:29:08for at least 300 million years -
0:29:08 > 0:29:10long before the dinosaurs.
0:29:10 > 0:29:14If you look at them, it's kind of a mix between a ray and a shark.
0:29:14 > 0:29:15Yes.
0:29:20 > 0:29:24Chimaeras can live for up to 30 years.
0:29:24 > 0:29:26Using their incredible sense of smell,
0:29:26 > 0:29:29they hunt for shellfish in the dark,
0:29:29 > 0:29:32grinding them up with tooth plates instead of rows of teeth.
0:29:39 > 0:29:43Those enormous eyes work hard to take advantage of any light
0:29:43 > 0:29:44that reaches the deep sea.
0:30:00 > 0:30:01Starfish.
0:30:01 > 0:30:03Oh, yeah, I think you're right.
0:30:03 > 0:30:05I haven't seen that guy before.
0:30:06 > 0:30:09Pelayo can only confirm a new species
0:30:09 > 0:30:11if he takes a sample to study.
0:30:12 > 0:30:15With a special permit from the Galapagos National Park,
0:30:15 > 0:30:18he's one of the only people with the authority to do this.
0:30:19 > 0:30:22For everything he collects and stores in these tanks,
0:30:22 > 0:30:27he carefully records every detail about the habitat it came from.
0:30:29 > 0:30:31It may appear invasive,
0:30:31 > 0:30:35but taking these samples will help scientists to understand
0:30:35 > 0:30:37how to better protect species in the deep sea.
0:30:39 > 0:30:45Despite the fact that we're aware of how much we take from the planet,
0:30:45 > 0:30:47- these samples are very important, aren't they?- Yeah.
0:30:47 > 0:30:52People only care about what they know and from here we know nothing.
0:30:53 > 0:30:56Then something else catches Pelayo's eye -
0:30:56 > 0:30:59a soft coral he's never seen before.
0:30:59 > 0:31:00Move on, Pelayo?
0:31:00 > 0:31:03No. Can we get Toby to grab that one?
0:31:04 > 0:31:07This guy here, this soft coral.
0:31:07 > 0:31:10I've got another sample for you, Toby.
0:31:24 > 0:31:27Our search continues as we make our way up the slope.
0:31:36 > 0:31:40Until another creature of the deep makes an appearance
0:31:40 > 0:31:42and steals the show.
0:31:47 > 0:31:52Pelayo thinks it is a type of deep-sea warty octopus,
0:31:52 > 0:31:55and it's never been recorded in the Galapagos before.
0:32:11 > 0:32:13She's carrying eggs
0:32:13 > 0:32:17and will guard them for up to four and a half years,
0:32:17 > 0:32:19longer than any other animal on the planet.
0:32:49 > 0:32:51Our time in the abyss has come to an end.
0:32:53 > 0:32:54Here we go, kids.
0:32:55 > 0:32:5735 metres to go.
0:32:57 > 0:33:00- Is that it? We're back in the real world.- Nearly there.
0:33:17 > 0:33:19Welcome back, everybody.
0:33:19 > 0:33:21- Wow.- Hello, Galapagos.
0:33:32 > 0:33:33That experience...
0:33:34 > 0:33:38..is probably the most exhilarating thing I will ever do
0:33:38 > 0:33:39in my entire life.
0:33:39 > 0:33:41That has trumped, officially trumped,
0:33:41 > 0:33:44anything I've done in my entire life, personal and professional.
0:33:50 > 0:33:53And you really did say, you know, "It'll fly by".
0:33:53 > 0:33:55And I was like, "Yeah, but it's seven hours".
0:33:55 > 0:33:57It flew by.
0:33:58 > 0:34:01So our job isn't done for the day.
0:34:01 > 0:34:05Because now we've all these amazing samples to take a look at.
0:34:07 > 0:34:11In the ship's wet lab, Pelayo quickly begins to analyse
0:34:11 > 0:34:15everything he's collected today - 16 samples in total.
0:34:18 > 0:34:24So we're going to start with the first sample, which is this star
0:34:24 > 0:34:26we collected at 1,000 metres deep.
0:34:28 > 0:34:31So is this a specimen that you're familiar with?
0:34:31 > 0:34:35No. When we were down there, it was the first time we saw this.
0:34:35 > 0:34:40We take a small sample for genetic analysis.
0:34:41 > 0:34:46DNA tests that can only be carried out on land will confirm
0:34:46 > 0:34:48if these are indeed new species.
0:34:49 > 0:34:51The process will take months,
0:34:51 > 0:34:54but Pelayo is confident that what we've found
0:34:54 > 0:34:57on these submerged volcanic slopes is new to science.
0:35:02 > 0:35:06If so, it means scientists will be one step closer to unravelling
0:35:06 > 0:35:09the mysteries of life in the deep.
0:35:09 > 0:35:12We're a funny old species. We want to explore new frontiers,
0:35:12 > 0:35:15we want to find out if there's life on Mars,
0:35:15 > 0:35:17which in itself is hugely important,
0:35:17 > 0:35:22and yet we've forgotten about this vast ocean that covers
0:35:22 > 0:35:24the majority of our planet.
0:35:24 > 0:35:28And for kilometres, down there,
0:35:28 > 0:35:30there is stuff just waiting to be discovered.
0:35:37 > 0:35:39While we've been exploring the deep,
0:35:39 > 0:35:43Alucia's mission control has been continuing to scan the sea floor.
0:35:50 > 0:35:53These 3-D maps show that Galapagos is littered
0:35:53 > 0:35:57with underwater volcanoes known as seamounts.
0:35:57 > 0:36:01Mission geologist Karen Harpp thinks some seamounts might explain
0:36:01 > 0:36:06how certain species dispersed across the island chain,
0:36:06 > 0:36:09adapting to each new environment they encountered.
0:36:09 > 0:36:14That seamount's really interesting to us because it has a structure,
0:36:14 > 0:36:16a shape that's not typical.
0:36:16 > 0:36:19- It looks very flat. - It is very flat.
0:36:19 > 0:36:22You need therefore a way to explain why it has such a flat top,
0:36:22 > 0:36:27and one of those ways is this notion that it is actually a sunken island.
0:36:28 > 0:36:32As this volcanic island slowly sank beneath the ocean,
0:36:32 > 0:36:36waves would have eroded down its peak into this flat shape.
0:36:37 > 0:36:41What you see when you look at the Galapagos today is only its current
0:36:41 > 0:36:44configuration. But if you go back even a half a million years,
0:36:44 > 0:36:47one million years, two million years,
0:36:47 > 0:36:50it turns out that very different islands were in different places,
0:36:50 > 0:36:54and we have to think of it as a very dynamic place.
0:36:54 > 0:36:55Which it surely is.
0:36:57 > 0:37:03So why is the presence of a drowned island important,
0:37:03 > 0:37:06with respect to our understanding of how animals might have
0:37:06 > 0:37:08dispersed from island to island?
0:37:08 > 0:37:11The way to think of it is as stepping stones.
0:37:11 > 0:37:14If you can shorten the distance between two islands, you increase
0:37:14 > 0:37:17the chances of a species getting relocated to that new island.
0:37:28 > 0:37:34Many species most likely floated to Galapagos by chance and once here,
0:37:34 > 0:37:38this island-hopping theory could explain how they were able to spread
0:37:38 > 0:37:42across the archipelago to even its farthest reaches.
0:37:47 > 0:37:50It's how the pink iguana could have made it
0:37:50 > 0:37:52to one of its most remote volcanoes.
0:37:55 > 0:38:01And how another iconic species can be found across most of Galapagos -
0:38:01 > 0:38:03the giant tortoise.
0:38:06 > 0:38:09Today, the largest population lives on Alcedo,
0:38:09 > 0:38:13a volcano whose enormous crater, known as a caldera,
0:38:13 > 0:38:16is rarely visited because it is so difficult to reach.
0:38:21 > 0:38:23It's where we're heading next.
0:38:23 > 0:38:26The expedition will be led by Pablo Valladares,
0:38:26 > 0:38:29a guide working with the Galapagos National Park.
0:38:31 > 0:38:34Alcedo has been hit by a drought this year,
0:38:34 > 0:38:38and many scientists predict that they'll only become more severe
0:38:38 > 0:38:40with climate change.
0:38:40 > 0:38:45Pablo doesn't know how badly the giant tortoises have been affected.
0:38:45 > 0:38:48One way to find out is to assess how well they're breeding.
0:38:51 > 0:38:54This is it - the Alcedo Volcano.
0:38:54 > 0:38:58Its caldera measures 6.4km in width.
0:38:58 > 0:39:01And there you can see plumes of volcanic gas.
0:39:01 > 0:39:05This volcano is still very much alive and active.
0:39:09 > 0:39:13We need to find a nice population of tortoises.
0:39:13 > 0:39:16How many tortoises are usually around this area, though?
0:39:16 > 0:39:19Well, on Alcedo there is an estimate of between
0:39:19 > 0:39:225,000 and 8,000 tortoises.
0:39:22 > 0:39:24Generally, when you get a mud pond, a wet area,
0:39:24 > 0:39:26that's where all of them congregate.
0:39:26 > 0:39:29So there's no mud ponds anywhere here, is there?
0:39:29 > 0:39:30It has been very dry.
0:39:41 > 0:39:44We head off in search of tortoises.
0:40:00 > 0:40:04Look at this, Liz - we're following a tortoise path.
0:40:04 > 0:40:07By generation and generation, tortoises have been walking,
0:40:07 > 0:40:09they've been walking, following on this path.
0:40:09 > 0:40:13You can see all the tracks of their feet and their bodies.
0:40:15 > 0:40:18Darwin himself noticed these well-worn tracks
0:40:18 > 0:40:22littering the landscape and that following them was the best chance
0:40:22 > 0:40:24of finding fresh water.
0:40:24 > 0:40:28Today, they lead us to a group of giant tortoises.
0:40:30 > 0:40:34On a day like today, this is exactly what reptiles need to be doing.
0:40:34 > 0:40:38They can't regulate their own body temperature like we can
0:40:38 > 0:40:42and it would be very silly of them to hang out in this 32-degree heat.
0:40:42 > 0:40:46So they're all huddled along what little shade they can find,
0:40:46 > 0:40:47all along this tortoise track.
0:40:47 > 0:40:51There's two here, there's two there, there's one over there.
0:40:54 > 0:40:58They really are magnificent primordial beasts.
0:41:02 > 0:41:06The Galapagos tortoise is one of the most long-lived creatures on Earth,
0:41:06 > 0:41:09with an average lifespan of 100 years.
0:41:10 > 0:41:15And they can weigh almost half a tonne, as much as five grown men.
0:41:26 > 0:41:30These gargantuan reptiles can survive for up to a year
0:41:30 > 0:41:32without any food or water.
0:41:32 > 0:41:35That has got to go a long way towards helping them to succeed
0:41:35 > 0:41:38in a challenging environment like this one.
0:41:41 > 0:41:42But are they breeding?
0:41:45 > 0:41:47Pablo soon finds evidence.
0:41:53 > 0:41:54These are tortoise nests.
0:41:54 > 0:41:55Look at all the shells, look.
0:41:56 > 0:41:58This is amazing.
0:41:58 > 0:42:02It's amazing. So this means tortoises are nesting here
0:42:02 > 0:42:04and babies are hatching out.
0:42:04 > 0:42:09This is the perfect spot for that because it is open,
0:42:09 > 0:42:14so it'll allow the sun rays to go through and warm up the nests.
0:42:15 > 0:42:18How many eggs do they lay at a time?
0:42:18 > 0:42:21There's an average of ten eggs, generally,
0:42:21 > 0:42:24and it depends on the tortoise population.
0:42:24 > 0:42:27Babies will never meet their mother.
0:42:27 > 0:42:29Or, if they do, they'll never know,
0:42:29 > 0:42:33because the female closes the nest and goes.
0:42:33 > 0:42:34They're on their own from the minute they hatch.
0:42:34 > 0:42:37Absolutely. It gives you hope.
0:42:37 > 0:42:40These are excellent signs that the tortoises are breeding.
0:42:40 > 0:42:41They're having babies.
0:42:45 > 0:42:49The hatchlings are nowhere to be seen, which is to be expected.
0:42:54 > 0:42:57The first stage of the giant tortoise's life is known
0:42:57 > 0:43:00as the lost years, as very little is known about them.
0:43:08 > 0:43:12With Galapagos hawks circling overhead,
0:43:12 > 0:43:16young tortoises need to remain hidden for several years
0:43:16 > 0:43:19until they're large enough to fend for themselves.
0:43:30 > 0:43:34It's an effective strategy that's contributed to their success here
0:43:34 > 0:43:35for millions of years.
0:43:39 > 0:43:41But with ever more severe droughts,
0:43:41 > 0:43:46new challenges will be pushing their survival strategies to the limit.
0:43:49 > 0:43:51Across the Galapagos,
0:43:51 > 0:43:55tortoises have evolved to suit their habitat perfectly.
0:44:03 > 0:44:05On the islands thick with vegetation,
0:44:05 > 0:44:09their dome-shaped shells help them to plough through the undergrowth.
0:44:12 > 0:44:16On more arid islands, where food is less plentiful,
0:44:16 > 0:44:19their shells are saddle-shaped, with a peak at the front,
0:44:19 > 0:44:22allowing them to reach the fruit of tall cacti.
0:44:24 > 0:44:29Each tortoise is beautifully adapted to the island it came to inhabit,
0:44:29 > 0:44:33resulting in 11 different types of Galapagos tortoise today.
0:44:34 > 0:44:38But why are the environments across this small group of islands
0:44:38 > 0:44:39so varied?
0:44:43 > 0:44:47The answer can be found deep inside the Earth,
0:44:47 > 0:44:51beneath this giant plate of rock on which the Galapagos sits.
0:44:59 > 0:45:04Below Alcedo is a hot spot where magma wells up,
0:45:04 > 0:45:07producing active volcanoes at the surface.
0:45:08 > 0:45:13But these islands sit on a tectonic plate that moves slowly
0:45:13 > 0:45:15over the hot spot.
0:45:15 > 0:45:17Like a conveyor belt,
0:45:17 > 0:45:21the newly-formed volcanic islands are pulled away from the hot spot
0:45:21 > 0:45:23and, over time, they become inactive.
0:45:28 > 0:45:32This island is drifting across the Earth's surface at a rate
0:45:32 > 0:45:35of about seven centimetres a year.
0:45:35 > 0:45:39The tectonic plate is carrying it, and the entire archipelago,
0:45:39 > 0:45:42in that direction, towards the south-east.
0:45:42 > 0:45:43It may not sound like much,
0:45:43 > 0:45:47but in the 700,000 years since Isabela first formed,
0:45:47 > 0:45:51it has moved 50km from its birthplace.
0:45:53 > 0:45:57In just a few million years, as they travel away from the hot spot,
0:45:57 > 0:46:02the islands transform from active volcanoes of barren rock,
0:46:02 > 0:46:05to landscapes filled with lush vegetation,
0:46:05 > 0:46:08covered in mist and cloud,
0:46:08 > 0:46:11until, finally, they sink beneath the waves.
0:46:14 > 0:46:17This is the reason why each Galapagos island
0:46:17 > 0:46:19is so dramatically different to the next,
0:46:19 > 0:46:22and why each island's inhabitants have had to adapt
0:46:22 > 0:46:25in really specific ways in order to survive on them,
0:46:25 > 0:46:29ending up completely different to their counterparts on other islands.
0:46:43 > 0:46:47The wildlife of the Galapagos is a product of this dynamic,
0:46:47 > 0:46:49ever-changing landscape.
0:46:50 > 0:46:55This cycle of island birth and death has forced species here
0:46:55 > 0:46:58to evolve and survive, or die.
0:47:14 > 0:47:16The focus of our final mission...
0:47:17 > 0:47:19..is an animal that's hard to miss
0:47:19 > 0:47:21along the island's coastline.
0:47:25 > 0:47:26The marine iguana.
0:47:35 > 0:47:40When Darwin first encountered them, he was both fascinated and repulsed,
0:47:40 > 0:47:42describing them as, "imps of darkness."
0:47:46 > 0:47:48This unusual habit of sneezing salt...
0:47:50 > 0:47:53..surely contributed to this reputation.
0:48:10 > 0:48:13I am keen to have an encounter with these fascinating reptiles.
0:48:15 > 0:48:19To see them in their element, I'm going to dive with them.
0:48:30 > 0:48:34These are the world's only seagoing lizards.
0:48:36 > 0:48:39Down here, you can see just how much they've changed
0:48:39 > 0:48:43over millions of years, compared to their land ancestors...
0:48:45 > 0:48:49..and why Darwin was interested in their remarkable adaptations
0:48:49 > 0:48:50to the marine environment.
0:48:52 > 0:48:56The largest individuals can hold their breath for over an hour.
0:48:58 > 0:49:01They've developed strong, hooked claws to cling to the rocks...
0:49:06 > 0:49:09..and blunt snouts full of razor-sharp teeth
0:49:09 > 0:49:12to graze on the only food they eat - algae.
0:49:16 > 0:49:20But every few years, this precious food source disappears,
0:49:20 > 0:49:23proving catastrophic for the marine iguanas.
0:49:42 > 0:49:47Our mission is to study how these extraordinary animals are adapting
0:49:47 > 0:49:48to this threat.
0:49:53 > 0:49:55To do this, we've brought our lab with us
0:49:55 > 0:49:59to carry out a ground-breaking experiment in the field.
0:50:02 > 0:50:06Professor Greg Lewbart is a wild animal vet.
0:50:06 > 0:50:09The marine iguana has been his focus for the last three years.
0:50:12 > 0:50:14It's such a unique animal.
0:50:14 > 0:50:17The marine iguana can be sort of an indicator species
0:50:17 > 0:50:19to the overall health of the islands.
0:50:22 > 0:50:27Every few years, a major weather event, El Nino, hits Galapagos...
0:50:29 > 0:50:32..and many scientists think they're getting stronger
0:50:32 > 0:50:33with climate change.
0:50:36 > 0:50:41During an El Nino, marine nutrient levels drop and the algae dies,
0:50:41 > 0:50:44directly impacting on marine iguana numbers.
0:50:46 > 0:50:51In 1983, 60% of marine iguanas were lost across the Galapagos.
0:50:51 > 0:50:55In 1998, 90% of them died on some islands.
0:50:55 > 0:50:59Marine iguana populations here take a regular beating.
0:51:00 > 0:51:04Greg has been tracking individual marine iguanas and measuring them.
0:51:06 > 0:51:08He's observed something extraordinary.
0:51:10 > 0:51:13It appears that they're actually, at least some of them,
0:51:13 > 0:51:17are getting shorter in order to survive El Nino events.
0:51:17 > 0:51:21If you're smaller, you're going to need less food,
0:51:21 > 0:51:24you're going to expend less energy,
0:51:24 > 0:51:29and your odds of surviving are going to be significantly better.
0:51:29 > 0:51:33We're not talking about animals that are just getting smaller
0:51:33 > 0:51:36in terms of their size, like someone who loses weight.
0:51:36 > 0:51:38- Right.- They're actually shortening,
0:51:38 > 0:51:41and that's really unheard of
0:51:41 > 0:51:44in animals with backbones.
0:51:44 > 0:51:49In addition to being able to shrink, they can grow again.
0:51:49 > 0:51:51OK, so when you're talking about shrinking,
0:51:51 > 0:51:54you don't mean generation on generation.
0:51:54 > 0:51:59You mean individual iguanas, in their lifetimes,
0:51:59 > 0:52:00are getting longer and shorter.
0:52:00 > 0:52:03Yes. Kind of like an accordion.
0:52:03 > 0:52:06So like a lizard accordion. I know, it's hard to comprehend.
0:52:07 > 0:52:12To explore how these iguanas alter their size so dramatically,
0:52:12 > 0:52:16we're going to do something that's never been attempted before.
0:52:16 > 0:52:20We're X-raying the iguanas with this cutting-edge portable machine.
0:52:21 > 0:52:26No-one has ever radiographed marine iguanas in the field like this.
0:52:26 > 0:52:27So the iguana sits here.
0:52:27 > 0:52:29- Yes.- This takes the X-ray.
0:52:29 > 0:52:33Does the iguana not try to scurry off the plate?
0:52:33 > 0:52:35Well, no-one has ever done this before, so we're not sure.
0:52:35 > 0:52:41OK, but step one is to catch them off those slippery rocks by the sea.
0:52:41 > 0:52:45- Yes.- Whose job is that, everybody's? - That's the fun part.- OK!
0:53:12 > 0:53:14You got one?
0:53:14 > 0:53:16- Hey.- Fantastic.
0:53:16 > 0:53:19It's a perfect, perfect first iguana for this.
0:53:19 > 0:53:23How much can they tolerate handling before we need to release them?
0:53:23 > 0:53:25- Quite a bit.- Yeah?
0:53:25 > 0:53:28You'll see that these animals are really pretty relaxed.
0:53:28 > 0:53:33Some animals, when you put them on their back, they go into a trance.
0:53:33 > 0:53:37So chickens do this, alligators do this,
0:53:37 > 0:53:40- and fortunately marine iguanas do this.- I love it.
0:53:40 > 0:53:43It's a behaviour that Darwin first identified -
0:53:43 > 0:53:47animals playing dead to discourage predators.
0:53:47 > 0:53:50It's 78.3.
0:53:51 > 0:53:55These heavy, lead overalls are a little cumbersome for the beach,
0:53:55 > 0:53:57but they're designed to protect us from the X-rays.
0:53:57 > 0:54:00- This is extra large. - What are you saying?
0:54:02 > 0:54:06So you got the medium and I get the extra large? I'm not going to take it personally, I'm not. It's fine.
0:54:06 > 0:54:09- Oh, it is heavy. - Yes. Now, go, turn around.
0:54:10 > 0:54:12- Are you ready, Andy? - Yes, I am ready.
0:54:12 > 0:54:13You better be a good iguana.
0:54:13 > 0:54:15I'm not going to try to do any restraint on him, OK, Andy?
0:54:19 > 0:54:21- Are you ready?- Yes, I'm ready.
0:54:21 > 0:54:25One, two, three.
0:54:25 > 0:54:26MACHINE BEEPS
0:54:26 > 0:54:28Done.
0:54:28 > 0:54:30- Good catch.- Got you.
0:54:33 > 0:54:34How does that feel?
0:54:34 > 0:54:37It feels great. We've been wanting to do this for a couple of years,
0:54:37 > 0:54:38and we've been dreaming about it.
0:54:40 > 0:54:43By X-raying the skeletons of these iguanas,
0:54:43 > 0:54:46Greg will be able to confirm how they achieve
0:54:46 > 0:54:48this incredible transformation.
0:54:51 > 0:54:55His plan is to return and X-ray the same individuals,
0:54:55 > 0:54:57and by comparing the data,
0:54:57 > 0:55:00he'll be able to see how these reptiles might break down
0:55:00 > 0:55:02and rebuild bone tissue.
0:55:11 > 0:55:14- Ready for release?- All right, buddy.
0:55:14 > 0:55:15You picked a great one. You got a good one.
0:55:15 > 0:55:17He was really well behaved.
0:55:17 > 0:55:21This research is revealing just how quickly these animals
0:55:21 > 0:55:24are responding to challenges.
0:55:24 > 0:55:27Who knows? If they survive to the next El Nino,
0:55:27 > 0:55:31we're pretty sure they could shrink again.
0:55:31 > 0:55:35Marine iguanas have not only been evolving over millennia,
0:55:35 > 0:55:39they're capable of adapting to change in just a few months.
0:55:42 > 0:55:45To me, it's like a magic trick.
0:55:45 > 0:55:48I bet Darwin didn't know that iguanas were shrinking,
0:55:48 > 0:55:49but he wasn't here long enough.
0:55:58 > 0:56:03I'm astounded by the number of ways marine iguanas have adapted
0:56:03 > 0:56:06to everything these islands have thrown at them,
0:56:06 > 0:56:09ever since their ancestors arrived here millions of years ago,
0:56:09 > 0:56:13by chance, on floating rafts of vegetation.
0:56:13 > 0:56:17And, for me, they represent what the Galapagos is all about.
0:56:30 > 0:56:35Our journey so far has revealed how this dynamic island chain
0:56:35 > 0:56:38continues to shape the extraordinary wildlife here.
0:56:40 > 0:56:43And how animals are adapting to change,
0:56:43 > 0:56:46no matter how challenging the circumstances.
0:56:50 > 0:56:53'Next time on Mission Galapagos,
0:56:53 > 0:56:58'we'll dive into some of the most shark-infested waters on the planet,
0:56:58 > 0:57:00'to discover why hammerheads congregate here
0:57:00 > 0:57:02'in such huge numbers.'
0:57:02 > 0:57:04Oh, my God, look at this.
0:57:04 > 0:57:06LIZ YELLS
0:57:06 > 0:57:09'We'll investigate how sea lions are faring
0:57:09 > 0:57:11'in the face of climate change.'
0:57:12 > 0:57:15I'm trying to keep up with him as he spins, spins, spins,
0:57:15 > 0:57:16and I'm exhausted.
0:57:16 > 0:57:19'Search for an elusive ocean giant,
0:57:19 > 0:57:22'to find out what it gets up to in the deep.'
0:57:22 > 0:57:24Coming right in.
0:57:24 > 0:57:26GASPING Oh, my God.
0:57:26 > 0:57:29'And experience the power of the Pacific,
0:57:29 > 0:57:32'100 metres below the waves.'
0:57:32 > 0:57:33Oh, God, that was close.