0:00:15 > 0:00:19Mexico. A wild land.
0:00:21 > 0:00:24The animals that live here do so in greater numbers
0:00:24 > 0:00:27and variety than almost anywhere else on Earth.
0:00:31 > 0:00:34With so much at stake,
0:00:34 > 0:00:39one man has fought tirelessly to protect the wildlife of Mexico,
0:00:39 > 0:00:44but there's a particular creature he's devoted his life to saving.
0:00:47 > 0:00:50Rodrigo Medellin is the champion
0:00:50 > 0:00:54of one of the world's most hated animals - bats.
0:00:57 > 0:00:58There's little bats,
0:00:58 > 0:01:01there's big bats, there's short-snouted, long-snouted,
0:01:01 > 0:01:06big eyes, little eyes, long ears, short ears - every type of bat.
0:01:07 > 0:01:11He is embarking on the culmination of his life's work -
0:01:11 > 0:01:14a mission to save both his favourite bat
0:01:14 > 0:01:19and the legendary drink of Mexico - tequila.
0:01:21 > 0:01:24In Mexico and in other places because of what I do,
0:01:24 > 0:01:25they call me the bat man.
0:01:26 > 0:01:33All I want is that people get the right information about bats
0:01:33 > 0:01:35and about how important they are for us
0:01:35 > 0:01:42and if that entails them calling me the bat man, so be it.
0:01:42 > 0:01:43I AM the bat man.
0:01:56 > 0:02:00Rodrigo Medellin was not like other children.
0:02:00 > 0:02:04While his friends kept gerbils and hamsters,
0:02:04 > 0:02:07Rodrigo's pets were vampire bats.
0:02:09 > 0:02:11I remember when I was a kid,
0:02:11 > 0:02:15I would keep vampire bats in the bathroom of my home,
0:02:15 > 0:02:19feeding them blood from cows - or from me, sometimes -
0:02:19 > 0:02:25keeping blood in the fridge so that I could feed the bats every night.
0:02:25 > 0:02:30That was not easy to withstand, and still my parents let me do that.
0:02:30 > 0:02:35It was fascinating to me to see these bats feeding and interacting
0:02:35 > 0:02:39with each other, and they'd take care of each other so well.
0:02:39 > 0:02:41It was a lot of fun.
0:02:43 > 0:02:46It was the beginning of a lifetime's obsession.
0:02:49 > 0:02:52But Rodrigo grew up in a world that loathes bats.
0:02:55 > 0:03:00In the 19th century, there was this author who wrote a book
0:03:00 > 0:03:06entitled Dracula, that really touched the imagination of people
0:03:06 > 0:03:08around the world
0:03:08 > 0:03:14and that has turned bats into monsters, unfortunately.
0:03:21 > 0:03:24Bats were so hated in Mexico
0:03:24 > 0:03:26because of their association with evil
0:03:26 > 0:03:29that people would hunt them down and kill them,
0:03:29 > 0:03:30burning them in their caves.
0:03:33 > 0:03:35Their populations crashed.
0:03:36 > 0:03:40To this day, people are afraid,
0:03:40 > 0:03:43saying that they're filthy,
0:03:43 > 0:03:48and that they are everything bad in the world.
0:03:48 > 0:03:50That is really not the case at all.
0:03:52 > 0:03:56A kilometre into a mountain south of Mexico City,
0:03:56 > 0:03:59Rodrigo is searching for a bat so persecuted
0:03:59 > 0:04:02that it was nearly lost for ever.
0:04:02 > 0:04:06It's called the lesser long-nosed bat, or tequila bat.
0:04:09 > 0:04:12This is one of his favourite childhood haunts.
0:04:14 > 0:04:19For most people, caves would sound like a terrifying place,
0:04:19 > 0:04:21like a place where they don't belong.
0:04:21 > 0:04:25But caves are my perfect place.
0:04:25 > 0:04:28Caves are an incredibly peaceful place.
0:04:29 > 0:04:32Rodrigo has spent much of the last 20 years underground,
0:04:32 > 0:04:34working to save the tequila bat.
0:04:36 > 0:04:40Bat guano all over.
0:04:40 > 0:04:44Under that layer of bat faeces
0:04:44 > 0:04:48is a whole layer of living insects.
0:04:48 > 0:04:52Beetles, beetle larvae, fly larvae,
0:04:52 > 0:04:55moth larvae, that are just moving everything, everything, everything.
0:04:55 > 0:04:57You look and everything is moving.
0:04:59 > 0:05:04Because bats move from cave to cave, he never knows what he'll find.
0:05:04 > 0:05:07As he approaches the roost, he must leave his lantern outside.
0:05:10 > 0:05:13Our cameras can see what he cannot.
0:05:15 > 0:05:17No-one has seen this before.
0:05:19 > 0:05:23Look at this. There are so many bats around us.
0:05:25 > 0:05:28In this beautiful space.
0:05:28 > 0:05:32There are thousands of bats here, of many different species -
0:05:32 > 0:05:34perhaps even the ones he's after.
0:05:35 > 0:05:37But Rodrigo can't see them.
0:05:39 > 0:05:41If I close my eyes now,
0:05:41 > 0:05:48it's exactly the same as if I have them open, I see absolutely nothing.
0:05:48 > 0:05:50In terms of my ears,
0:05:50 > 0:05:54I am hearing a stream of bats coming from that direction around me
0:05:54 > 0:05:59and passing through, and then a bunch of bats squealing back there.
0:06:01 > 0:06:05I can picture a map of the cave in my head.
0:06:05 > 0:06:08The bats also navigate using their ears,
0:06:08 > 0:06:12but they have evolved the ability to see with sound.
0:06:12 > 0:06:16They make high-pitched sounds beyond our hearing
0:06:16 > 0:06:19and listen for their echoes off objects.
0:06:19 > 0:06:21This how they can fly in the dark.
0:06:22 > 0:06:25This is what is called the hall of hell -
0:06:25 > 0:06:32temperatures well above our comfort zone, close to 38-40 degrees Celsius,
0:06:32 > 0:06:36very high relative humidity - all of my clothes are completely wet.
0:06:36 > 0:06:40People associate this heat with hell.
0:06:40 > 0:06:43But I feel perfectly at home here.
0:06:45 > 0:06:48Rodrigo pushes into the deepest chamber
0:06:48 > 0:06:51to find out if his precious tequila bats are here.
0:06:53 > 0:06:57He may not be able to see the bats, but the guano beneath his feet
0:06:57 > 0:07:00is a vivid history of what's lived in this cave.
0:07:03 > 0:07:05And Rodrigo knows his guano.
0:07:06 > 0:07:13Oh, yes - this is a lump of lesser long-nosed bat poop.
0:07:13 > 0:07:16This tells me that this is indeed a lesser long-nosed bat colony.
0:07:18 > 0:07:23They're here, and thanks to Rodrigo's work, they're safe.
0:07:25 > 0:07:30Today, gates and guardians protect this cave.
0:07:30 > 0:07:33Now Rodrigo must catch one to see if they're healthy.
0:07:35 > 0:07:37To do this without harming them,
0:07:37 > 0:07:42he uses mist nets, too fine for the bats' echolocation to detect.
0:07:42 > 0:07:45My first lesser long-nosed bat came into my hands
0:07:45 > 0:07:50when I was, like, 15. We knew nothing about it.
0:07:50 > 0:07:53Then we found out that they were really endangered.
0:07:53 > 0:07:57We were looking at roosts that were known to have
0:07:57 > 0:08:00many thousands of lesser long-nosed bats
0:08:00 > 0:08:04and when we visited them, they only had a few hundreds or none.
0:08:04 > 0:08:07That immediately told us that they were in trouble.
0:08:08 > 0:08:12So this is one of my best friends.
0:08:12 > 0:08:19This is the lesser-long nosed bat. This is an amazing animal
0:08:19 > 0:08:22that migrates for thousands of kilometres.
0:08:22 > 0:08:26It's a small, but powerful flier. Look at this amazing wing.
0:08:29 > 0:08:34This is what made bats so successful in the night skies.
0:08:34 > 0:08:40Long-fingered hand here and a very long arm here.
0:08:40 > 0:08:43You can see both vein down here
0:08:43 > 0:08:47and a series of muscles stretches here.
0:08:48 > 0:08:50It's very much alive,
0:08:50 > 0:08:56so that they can control making it broader or narrower.
0:08:57 > 0:09:02That makes them masters of the air.
0:09:02 > 0:09:06It's getting ready to start a really exciting time,
0:09:06 > 0:09:08a really demanding time,
0:09:08 > 0:09:12a really dangerous time too, which is migration.
0:09:15 > 0:09:19The migration of this tiny endangered bat
0:09:19 > 0:09:22is one of the greatest in the animal world.
0:09:22 > 0:09:24This epic journey happens at night,
0:09:24 > 0:09:28so it's taken Rodrigo 20 years to work out their route.
0:09:29 > 0:09:34Over his life, he has discovered many of the roosts they use
0:09:34 > 0:09:39on their 2,000-kilometre journey and protected them, one by one.
0:09:42 > 0:09:47The entire migration is powered by nectar.
0:09:47 > 0:09:51I'm going to give it a bit of sugar water here.
0:09:53 > 0:09:56This incredible tongue that they have
0:09:56 > 0:09:59is the perfect instrument for them
0:09:59 > 0:10:03to reach into deep flowers like agave flowers.
0:10:05 > 0:10:09It's incredible that an animal this big can do what these guys do.
0:10:11 > 0:10:15I love them because of that.
0:10:15 > 0:10:20Rodrigo is about to immerse himself in the bats' world.
0:10:20 > 0:10:22By tracking their entire migration,
0:10:22 > 0:10:27he wants to see if he's achieved what many thought impossible -
0:10:27 > 0:10:29saving the tequila bats from extinction.
0:10:31 > 0:10:35The stakes are high - their fate is tied to Mexico's most famous export.
0:10:38 > 0:10:40As a Mexican, I am proud of my country
0:10:42 > 0:10:48and part of the Mexican spirit is a beverage
0:10:48 > 0:10:49that is called tequila.
0:10:55 > 0:11:00These spiky plants are the source of tequila.
0:11:00 > 0:11:05Tequila is a very important part of the Mexican economy
0:11:05 > 0:11:07and it is owed to bats.
0:11:12 > 0:11:17Bats provide pollination for the tequila plant, the agave plant.
0:11:21 > 0:11:24Mexico relies on tequila.
0:11:24 > 0:11:28Over a quarter of a billion litres were exported last year.
0:11:30 > 0:11:35Every plant is harvested by hand by men called jimadores...
0:11:38 > 0:11:41..in a trade passed down from father to son.
0:11:44 > 0:11:48The agaves are planted where they've always grown -
0:11:48 > 0:11:50in the flight path of the bats.
0:12:03 > 0:12:07What agaves do is, they grow and grow and grow
0:12:07 > 0:12:13and then when the time comes, they send this amazing shoot,
0:12:13 > 0:12:17huge flowering stalk, up into the sky.
0:12:17 > 0:12:21They invest all of their energy that they have accumulated over 15 years
0:12:21 > 0:12:24into one single reproductive event
0:12:24 > 0:12:27that basically costs them their lives.
0:12:27 > 0:12:31The link that they formed has been here for millions of years.
0:12:32 > 0:12:36Agaves rely on the bats to move their pollen.
0:12:36 > 0:12:40Bats rely on agaves so that they can survive.
0:12:42 > 0:12:47We could not have this amazing product
0:12:47 > 0:12:51if it wasn't for the bats, and I can't help but think of the bats
0:12:51 > 0:12:56and thank the bats for the incredible service they give us.
0:13:04 > 0:13:06Without the bats, there would be no tequila.
0:13:15 > 0:13:17Bats are so vital in spreading pollen and seeds
0:13:17 > 0:13:21that they're known as the farmers of the tropics.
0:13:25 > 0:13:28Without them, our crops and forests would collapse,
0:13:28 > 0:13:31with terrible consequences for us all.
0:13:39 > 0:13:41The tequila bats' journey takes them west...
0:13:45 > 0:13:49..and they sweep through the valleys and plains of Central Mexico.
0:13:52 > 0:13:56The land beneath them changes constantly.
0:13:58 > 0:14:00And always, they pass over us.
0:14:04 > 0:14:09Until 500km west of where they started,
0:14:09 > 0:14:14they hit the Pacific Ocean, and the uninhabited islands of Chamela.
0:14:24 > 0:14:27Rodrigo has heard reports that the bats have been gathering here.
0:14:31 > 0:14:34He's never been to this cave before.
0:14:44 > 0:14:51To his horror, it's full of cockroaches - he hates cockroaches.
0:14:51 > 0:14:54So many cockroaches, and I almost fell on them!
0:14:59 > 0:15:02But he's astonished by what he finds.
0:15:02 > 0:15:05This is incredible.
0:15:08 > 0:15:14So many lesser-long nosed bats, all around me.
0:15:14 > 0:15:21It's so good to see that their numbers are stable and big.
0:15:21 > 0:15:25The tequila bats have come together from all across Mexico
0:15:25 > 0:15:27with one thing on their minds.
0:15:47 > 0:15:51They're mating here right now,
0:15:51 > 0:15:55and this is a very well protected cave.
0:15:55 > 0:15:56The ocean takes care of that.
0:16:00 > 0:16:04While Lucas, the boatman, tucks into some oysters,
0:16:04 > 0:16:07Rodrigo pushes deeper into the cave,
0:16:07 > 0:16:10and the source of the bats' aphrodisiac.
0:16:12 > 0:16:14Oh, yes!
0:16:14 > 0:16:19A big male, which is what we expected in this cave.
0:16:19 > 0:16:23It's full of males getting ready to reproduce.
0:16:26 > 0:16:32Such well-tempered bat, with big testicles ready for action,
0:16:32 > 0:16:36loaded with sperm and ready for the females that are gathering
0:16:36 > 0:16:41here in this cave, and this should have a patch on its back.
0:16:41 > 0:16:44Oh, yeah - the patch is there, very oily.
0:16:44 > 0:16:47I can feel it with my finger here.
0:16:47 > 0:16:49That patch is put there by the males.
0:16:49 > 0:16:52They put faeces and urine and saliva there,
0:16:52 > 0:16:54and that is very attractive to the females.
0:16:54 > 0:16:57The females are going to come and take a whiff of that
0:16:57 > 0:17:00and just fall in love with this guy.
0:17:00 > 0:17:03This boy is ready to mate
0:17:03 > 0:17:07and it's time to let him go so that he can do his deed.
0:17:09 > 0:17:10There you go, my friend.
0:17:14 > 0:17:16On the roof of this cave,
0:17:16 > 0:17:19an extraordinary mass seduction is taking place.
0:17:21 > 0:17:25Once the females find a male whose sex potion entrances them,
0:17:25 > 0:17:29they'll choose him as their mate.
0:17:29 > 0:17:32And in three months, 1,500 kilometres away,
0:17:32 > 0:17:35a single baby bat will be born.
0:17:38 > 0:17:40It may be alluring for the females,
0:17:40 > 0:17:45but for Rodrigo, the smell is overpowering.
0:17:45 > 0:17:49This is a really stinky cave,
0:17:49 > 0:17:53and there's lots and lots of bats here.
0:17:53 > 0:17:54Lots of them everywhere.
0:17:56 > 0:17:57And this is...oh!
0:17:57 > 0:18:02And this is certainly a challenging cave to be in, to be sure.
0:18:04 > 0:18:08Eventually, the smell and cockroaches are too much,
0:18:08 > 0:18:10even for the bat man.
0:18:22 > 0:18:25The bats will stay on this island for weeks,
0:18:25 > 0:18:27mating and building their strength
0:18:27 > 0:18:30before they continue on the next stage in their migration.
0:18:33 > 0:18:37It will be perhaps 30 sunsets until then.
0:18:37 > 0:18:40And each evening is a changing of the guard.
0:18:55 > 0:18:59As the birds of Mexico head home to roost...
0:19:03 > 0:19:09..all across this enormous country, bats are about to reclaim the night.
0:19:11 > 0:19:16Nowhere is this more spectacular than the bat volcano of Calakmul.
0:19:21 > 0:19:23Predators are gathering.
0:19:23 > 0:19:28It's called the bat volcano, because every night, it erupts.
0:19:47 > 0:19:50This is one of the greatest bat colonies on Earth.
0:19:50 > 0:19:55Perhaps as many as three million bats live here.
0:19:55 > 0:20:00To avoid being eaten, they form a living tornado, 200m tall.
0:20:02 > 0:20:03In this whirling mass,
0:20:03 > 0:20:08it's almost impossible for their predators to choose a target.
0:20:08 > 0:20:10But the bats must head to their feeding grounds,
0:20:10 > 0:20:13and they start to peel off across the forest.
0:20:21 > 0:20:23Now the hunters can strike.
0:20:28 > 0:20:30One bat narrowly escapes.
0:20:35 > 0:20:37Others aren't so lucky.
0:20:41 > 0:20:45Bat falcons and brown jays also swoop in to make their kills.
0:20:55 > 0:20:58But nothing can dent the swarm.
0:21:04 > 0:21:08They're heading for the cornfields across the forest.
0:21:08 > 0:21:11There, they will devour 20 tonnes of insect pests...
0:21:17 > 0:21:20..like this hatching armyworm moth.
0:21:20 > 0:21:23Each moth can produce hundreds of hungry caterpillars.
0:21:26 > 0:21:29And unprotected, the crops would be doomed.
0:21:35 > 0:21:40Most Mexicans don't realise they owe not only their tequila,
0:21:40 > 0:21:42but also their corn to bats.
0:21:48 > 0:21:50Thanks to bats, we're eating this.
0:21:53 > 0:21:57Rodrigo's main weapon to defend the bats is education.
0:21:57 > 0:22:01His teams work in over 30 states across Mexico,
0:22:01 > 0:22:04and he never misses a chance for a bit of bat PR.
0:22:49 > 0:22:52You can see it in the eyes of people when you talk to them
0:22:52 > 0:22:56and it makes sense - all of a sudden, everything makes sense.
0:22:57 > 0:23:04Their frame of mind changes and they're bat friends from then on
0:23:04 > 0:23:06and they propagate the message.
0:23:06 > 0:23:08They talk to people in the house,
0:23:08 > 0:23:10they talk to people in the office, school et cetera.
0:23:12 > 0:23:15And little by little, the situation goes snowballing
0:23:15 > 0:23:18and really, really changes the panorama for the bats.
0:23:20 > 0:23:22I can turn them around in ten minutes.
0:23:22 > 0:23:27In 15 minutes I give them the facts, I give them the evidence,
0:23:27 > 0:23:30I give them the images.
0:23:30 > 0:23:35Over 20 years, Rodrigo and his team have converted the people
0:23:35 > 0:23:37whose land the bats rely on
0:23:37 > 0:23:40from potential destroyers to bat defenders.
0:23:45 > 0:23:49Just a few centuries ago, bats were worshipped in Mexico.
0:23:51 > 0:23:55The darkest month was named after them
0:23:55 > 0:23:57and one of their gods was a bat.
0:23:59 > 0:24:01This is the rainforest of the Maya.
0:24:03 > 0:24:06Because the tequila bats have still not left their island,
0:24:06 > 0:24:10Rodrigo has a chance to return to the place he calls home.
0:24:17 > 0:24:21Once, a vast empire stretched across these lands.
0:24:23 > 0:24:25Now their temples, palaces,
0:24:25 > 0:24:28and sacrificial altars have been swallowed by the forest.
0:24:36 > 0:24:39This jungle is very special to Rodrigo.
0:24:41 > 0:24:46For here, 30 years ago, he helped create the Chajul field station.
0:24:50 > 0:24:53It has since become his base for bat research.
0:24:55 > 0:24:58I always look forward to my first morning,
0:24:58 > 0:25:02when I'm going to be woken up by the howlers calling.
0:25:05 > 0:25:09Nature right there, with you, just outside your window.
0:25:13 > 0:25:16It's great to be back. It's peaceful.
0:25:16 > 0:25:18It really feels like coming home.
0:25:28 > 0:25:31Every time I go into the forest looking for bats,
0:25:31 > 0:25:34there's something different going on.
0:25:36 > 0:25:38When the forest is alive,
0:25:38 > 0:25:42every little piece of the forest that you see has a secret to unveil.
0:25:45 > 0:25:49One of the first nights that I spent here,
0:25:49 > 0:25:55I set my mist nets and I was blown away by the diversity of bats,
0:25:55 > 0:25:59by the abundance of the bats.
0:25:59 > 0:26:02There's nothing like this anywhere else in Mexico.
0:26:02 > 0:26:06Not like this - this is 50, 40 species in a week.
0:26:07 > 0:26:12Many bats that I caught there had never been caught in Mexico before.
0:26:12 > 0:26:14So those are new records for the country.
0:26:20 > 0:26:25In a couple of nights, Rodrigo and his team catch 22 species.
0:26:25 > 0:26:29That's more types of bat than inhabit the entire British Isles.
0:26:37 > 0:26:40Flower nibblers,
0:26:40 > 0:26:43fruit gobblers,
0:26:43 > 0:26:46and even some bats that devour other bats...
0:26:49 > 0:26:51..leaving only their wings.
0:26:56 > 0:27:02And tonight, he's caught something very rare and very weird.
0:27:02 > 0:27:06It's got suckers in its thumbs and in its feet.
0:27:09 > 0:27:11And really real suckers.
0:27:12 > 0:27:14SOFT POP
0:27:14 > 0:27:16Beautiful.
0:27:17 > 0:27:22I have this glass - it's perfectly smooth
0:27:22 > 0:27:25and it's using its suckers to move around the glass.
0:27:27 > 0:27:32This sucker-footed bat can stick to the sides of curled-up jungle leaves
0:27:32 > 0:27:35in which it hides in the daytime.
0:27:35 > 0:27:41There's no other mammal or bird or reptile who have suckers like this.
0:27:41 > 0:27:44This is something really unique in the natural world.
0:27:44 > 0:27:47Now it's time to let him go.
0:27:47 > 0:27:49The suckers make it really hard to come out.
0:27:57 > 0:28:02Some gentle encouragement, and he's away.
0:28:02 > 0:28:03Go on.
0:28:07 > 0:28:12Finally, it's time for Rodrigo to return to the tequila bat island.
0:28:14 > 0:28:18It takes three days by boat, car and foot.
0:28:24 > 0:28:25The females are now pregnant
0:28:25 > 0:28:29and are ready to start their long journey north.
0:28:30 > 0:28:35They're not the only travellers who will set out tonight,
0:28:35 > 0:28:39for on the beach, new life is stirring.
0:28:39 > 0:28:45This is a miracle. This is many miracles happening right now.
0:28:49 > 0:28:54These are all olive ridley sea turtles.
0:28:54 > 0:29:00Their mother deposited the eggs here about two months ago
0:29:00 > 0:29:03and these newborns are incredibly powerful,
0:29:03 > 0:29:08having just pushed through about two feet of sand.
0:29:10 > 0:29:16And they're getting ready to go into the ocean.
0:29:16 > 0:29:17Good luck to you all!
0:29:21 > 0:29:25From this beach, the turtles will spread across the oceans.
0:29:26 > 0:29:30Those that survive will be pushed by their instincts
0:29:30 > 0:29:33and their memories to return to this beach to lay their eggs.
0:29:37 > 0:29:41It's this same urge to go back to the place of their birth
0:29:41 > 0:29:44that drives the mother tequila bats north.
0:29:44 > 0:29:47They too are returning to where they started life.
0:29:51 > 0:29:53Before they spread out across Mexico,
0:29:53 > 0:29:56Rodrigo has a rare chance to count them,
0:29:56 > 0:29:58and estimate how many there are.
0:30:00 > 0:30:04This is an amazing thing - I can't see anything.
0:30:04 > 0:30:06The cave is straight ahead of me,
0:30:06 > 0:30:11so this thermal camera can tell me what's going on there.
0:30:11 > 0:30:13Using this technology,
0:30:13 > 0:30:18we can estimate how many bats do we have in this cave.
0:30:18 > 0:30:23I'm guessing about 40,000 lesser long-nosed bats.
0:30:23 > 0:30:26This, of course, is chaos.
0:30:26 > 0:30:29I mean, really, they're going in every possible direction
0:30:29 > 0:30:32but the spectacle is incredible.
0:30:32 > 0:30:35This is staggering, considering that 20 years ago,
0:30:35 > 0:30:38when Rodrigo started to save them,
0:30:38 > 0:30:41many caves only had a few hundred bats, or none at all.
0:30:48 > 0:30:50The path the bats must now take
0:30:50 > 0:30:54lies between the mountains of the Sierra Madre and the sea.
0:30:54 > 0:30:58This fertile land is called the nectar corridor...
0:31:00 > 0:31:06..Because here, every year, billions of flowers open at night.
0:31:08 > 0:31:10The bats must feed on these constantly
0:31:10 > 0:31:14to fuel their journey, otherwise they'll die.
0:31:14 > 0:31:16And they have to time it perfectly.
0:31:18 > 0:31:23Over millions of years, the bats have learned by trial and death
0:31:23 > 0:31:26to track where the nectar is going to show up next.
0:31:28 > 0:31:32Bats are early or bats are late, plants die and bats die.
0:31:36 > 0:31:40What the bats miss is hoovered up quickly in the daytime,
0:31:40 > 0:31:44in a fiesta of hummingbirds.
0:31:46 > 0:31:52But both hummingbird and bat face an uncertain future.
0:31:52 > 0:31:55Humans are affecting every last corner of the world
0:31:55 > 0:31:59in many different ways, some ways that we still don't understand.
0:32:00 > 0:32:04Biological diversity is under threat from many angles,
0:32:04 > 0:32:11and not all of them are manageable or reversible by humans.
0:32:13 > 0:32:18Mexico is developing fast. The land the bats rely on
0:32:18 > 0:32:21is being swallowed and nature is being destroyed.
0:32:23 > 0:32:27But because of Rodrigo, at least some is safe.
0:32:29 > 0:32:3330 years ago, he was asked to assist the new government
0:32:33 > 0:32:36to devise laws to save the wildlife of Mexico.
0:32:38 > 0:32:40Land-owners, the Mexican people,
0:32:40 > 0:32:47worked as partners to create a vast network of linked nature reserves
0:32:47 > 0:32:50made from their private and the government's public land.
0:32:52 > 0:32:54I've worked with small groups, big groups,
0:32:54 > 0:32:57individuals, in the government halls, everywhere.
0:32:57 > 0:33:00All we need is a little bit of information
0:33:00 > 0:33:02and people are going to change about bats.
0:33:04 > 0:33:08Now, over a quarter of Mexico is protected land.
0:33:08 > 0:33:11Where other countries have lost much of their wildlife,
0:33:11 > 0:33:13Mexico is a rare success story.
0:33:16 > 0:33:19But nature in Mexico is still threatened
0:33:19 > 0:33:22and Rodrigo is still pushing to save more.
0:33:24 > 0:33:26This cave is one of the safe ones,
0:33:26 > 0:33:29protected by local families who share the land.
0:33:32 > 0:33:37Down here, Rodrigo and the bats feel safe.
0:33:40 > 0:33:45The peacefulness in here is really overwhelming.
0:33:45 > 0:33:47It's really nice.
0:33:47 > 0:33:52The only sound around you are the bats flying around you.
0:33:52 > 0:33:56This here is a bed of bat guano.
0:33:56 > 0:33:59I could just lie down here and take a nap.
0:33:59 > 0:34:01It would be a very nice nap.
0:34:02 > 0:34:04I just absolutely love it.
0:34:06 > 0:34:09But even in their deepest sanctuaries,
0:34:09 > 0:34:12where their bodies lie undisturbed by any scavenger,
0:34:12 > 0:34:14they're never quite secure.
0:34:14 > 0:34:17For this cave is called the cave of the serpents.
0:34:22 > 0:34:26Somehow, a group of snakes
0:34:26 > 0:34:29have learned that they can catch their food here.
0:34:30 > 0:34:33This is something I have never seen before.
0:34:33 > 0:34:36These are rat snakes.
0:34:36 > 0:34:40But they're getting used to eating bats inside the cave,
0:34:40 > 0:34:42as they come out.
0:34:44 > 0:34:48As darkness falls outside, the bats prepare to leave.
0:34:50 > 0:34:52From much deeper underground,
0:34:52 > 0:34:55they start to throng the narrow passages towards the surface.
0:34:57 > 0:34:59And the snakes start to emerge.
0:35:07 > 0:35:09Look at that!
0:35:12 > 0:35:17This snake is deep into the cave,
0:35:17 > 0:35:21where the bats are supposed to be completely safe from predators.
0:35:22 > 0:35:25Not so! Dinner.
0:35:28 > 0:35:31The bat dwarfs the snake's head.
0:35:31 > 0:35:35To swallow it, the snake must dislocate its jaw.
0:35:36 > 0:35:40This is one more danger that bats face
0:35:40 > 0:35:44along their migration,
0:35:44 > 0:35:47and still they're there and surviving.
0:35:56 > 0:35:59THUNDER CRASHES
0:35:59 > 0:36:03But just when the bat populations look safe, disaster strikes.
0:36:07 > 0:36:12Within weeks of each other, not one but two hurricanes hit Mexico
0:36:12 > 0:36:15and batter the entire Pacific coast.
0:36:19 > 0:36:22This is a threat beyond even Rodrigo's control.
0:36:27 > 0:36:29He loses the tequila bats.
0:36:33 > 0:36:36Across the country, he sends his students to everywhere
0:36:36 > 0:36:38the bats have ever been found.
0:36:41 > 0:36:44For three weeks they search, day and night.
0:36:49 > 0:36:51This has never happened before.
0:37:05 > 0:37:10Yeah, OK. So the bats are not here. Well, I don't know.
0:37:21 > 0:37:23If many of the bats have been killed,
0:37:23 > 0:37:26the future for their species is bleak.
0:37:41 > 0:37:44The way I feel right now, the trail is getting cold.
0:37:45 > 0:37:48I'm not sure if we're going to find them.
0:37:48 > 0:37:52Our only hope is to keep poking and looking
0:37:52 > 0:37:57in every little piece of bat habitat that we know of,
0:37:57 > 0:37:59to see if they are there.
0:38:03 > 0:38:08It's a tense time for Rodrigo. He puts out rewards for any leads.
0:38:11 > 0:38:15At last, one of his students thinks they've seen a tequila bat
0:38:15 > 0:38:17in a cave called Las Vegas.
0:38:24 > 0:38:28They block the exits and he heads in alone.
0:38:41 > 0:38:45Finally he emerges - triumphant.
0:38:46 > 0:38:48I found them!
0:38:48 > 0:38:51It took weeks of searching everywhere.
0:38:51 > 0:38:55It took two hurricanes to move the bats around
0:38:55 > 0:38:58so that we could not track them, but they're here.
0:38:58 > 0:39:04I got, like, er, maybe like ten, so the population is healthy.
0:39:05 > 0:39:08Another dot in the migration of this species.
0:39:08 > 0:39:10I'm so relieved. I've found them!
0:39:15 > 0:39:16Oh, wow!
0:39:23 > 0:39:27Oh, look at this! This is a pregnant female.
0:39:27 > 0:39:30Her wings are in great shape.
0:39:32 > 0:39:37Wow! I can feel the head right here and the rump over here.
0:39:37 > 0:39:40This is the baby right here. The baby is really big.
0:39:42 > 0:39:49I can't imagine the energy that this bat has spent
0:39:49 > 0:39:53just flying around with a foetus growing inside her.
0:39:53 > 0:39:55Thank you, mom. You're ready to go.
0:40:02 > 0:40:05With proof that there are bats here in numbers,
0:40:05 > 0:40:08he can get legal protection for the cave.
0:40:09 > 0:40:14The tequila bats have another vital place of permanent safety.
0:40:19 > 0:40:23For Rodrigo, it's time to visit some old friends.
0:40:29 > 0:40:32There are over 1,200 species of bats in the world.
0:40:38 > 0:40:40Three are vampires.
0:40:47 > 0:40:50And two of these species live in this cave.
0:40:57 > 0:40:59I got you!
0:40:59 > 0:41:02I thought this was a common vampire bat
0:41:02 > 0:41:04but it's a hairy-legged vampire bat.
0:41:05 > 0:41:07They're not common at all.
0:41:08 > 0:41:12This hairy-legged vampire bat feeds almost entirely
0:41:12 > 0:41:15on mammal blood in this area here.
0:41:15 > 0:41:18They have a really soft side, which is that they share blood.
0:41:18 > 0:41:23No vampire bat can afford to go one night without feeding.
0:41:23 > 0:41:28We found out that they'd come back from their foraging
0:41:28 > 0:41:31and regurgitate a little bit of the blood for the guys
0:41:31 > 0:41:34that didn't feed that night.
0:41:34 > 0:41:37So basically they have a blood cooperative going
0:41:37 > 0:41:40in every vampire bat colony.
0:41:41 > 0:41:43They are nice. I mean, look at them.
0:41:45 > 0:41:46Really nice.
0:41:51 > 0:41:55This might look like the stuff of nightmares,
0:41:55 > 0:41:57but the cow is oblivious
0:41:57 > 0:42:01to the vampires feeding on its back and sides.
0:42:01 > 0:42:07Vampire teeth are so sharp that the cow doesn't feel their bite,
0:42:07 > 0:42:11and an anticoagulant in their saliva keeps the blood flowing.
0:42:13 > 0:42:16They don't suck, but lick up the flowing juices.
0:42:19 > 0:42:23Often, they will return to feed on the same animal, night after night.
0:42:27 > 0:42:30Regrettably, Rodrigo can't stay for dinner.
0:42:32 > 0:42:35He's back on the trail of the tequila bats.
0:42:36 > 0:42:40He heads north to the end of the nectar corridor
0:42:40 > 0:42:43and the edge of the Pinacate desert.
0:42:45 > 0:42:51The Pinacate desert is one of the great deserts of North America.
0:42:51 > 0:42:54It is part of the Sonoran desert
0:42:54 > 0:42:59and as such is part of the driest desert in this continent.
0:43:00 > 0:43:04It is one of the most challenging places on Earth to make
0:43:04 > 0:43:09a living as a human being or survive as a species.
0:43:12 > 0:43:17This place has been a desert for at least 100,000 years.
0:43:21 > 0:43:26The bats are aiming for a cave, deep in the heart of this desert,
0:43:26 > 0:43:29in the badlands just south of the US border.
0:43:36 > 0:43:39There are no agaves to feed off en route.
0:43:41 > 0:43:43Instead, the tequila bats,
0:43:43 > 0:43:46nearing the end of their three-month pregnancy,
0:43:46 > 0:43:50must seek the flowers of the giant columnar cactuses.
0:43:51 > 0:43:56These flowers accommodate almost half of the bat's body into them.
0:43:57 > 0:44:03It means millions of years of evolution
0:44:03 > 0:44:08in which the flowers have become perfect receptacles
0:44:08 > 0:44:13for the bat's head and snout and tongue
0:44:13 > 0:44:19and the very long tongue of the bat goes into those flowers
0:44:19 > 0:44:25and lick the nectar out and they come out completely covered with pollen.
0:44:25 > 0:44:29They move out, they go to another columnar cactus
0:44:29 > 0:44:30and there is pollination.
0:44:32 > 0:44:35Because he knows the bats will come to the cactus flowers,
0:44:35 > 0:44:40Rodrigo has a chance to solve a puzzle that's long been on his mind.
0:44:42 > 0:44:44How far can they fly in one night?
0:44:54 > 0:44:58It is a female - very lively,
0:44:58 > 0:45:01in very, very good health.
0:45:01 > 0:45:05We're going to mark it with a blue powder.
0:45:07 > 0:45:13Rodrigo coats the bats he catches in harmless UV dust,
0:45:13 > 0:45:15which they will lick off and digest.
0:45:15 > 0:45:18We keep the head out so that the powder
0:45:18 > 0:45:23does not affect its senses.
0:45:23 > 0:45:25That should be enough.
0:45:27 > 0:45:31The bats will now head on to their roost.
0:45:31 > 0:45:34And if Rodrigo can find a glowing bat-dropping there, he can prove
0:45:34 > 0:45:38how far they've flown - at least, in theory.
0:45:38 > 0:45:40No-one has tried this before.
0:45:49 > 0:45:52At daybreak, 50km from the cactuses,
0:45:52 > 0:45:58Rodrigo finally arrives at the most important cave -
0:45:58 > 0:46:01the end point of their long journey.
0:46:02 > 0:46:05The birth cave of the tequila bats.
0:46:08 > 0:46:14This cave is the largest colony
0:46:14 > 0:46:19that this bat has anywhere in the world.
0:46:20 > 0:46:24It's Rodrigo's great hope that enough bats have made it here
0:46:24 > 0:46:26to sustain their population.
0:46:28 > 0:46:32The future of the species depends on what will take place
0:46:32 > 0:46:34in this ancient volcano.
0:46:35 > 0:46:39We cannot get in the cave during the day.
0:46:39 > 0:46:44We would create chaos, worrying females
0:46:44 > 0:46:46that are taking care of their babies.
0:47:03 > 0:47:05Rodrigo must wait by the cave mouth.
0:47:08 > 0:47:09Night falls.
0:47:18 > 0:47:19And then...
0:47:22 > 0:47:27At first a trickle, then more emerge.
0:47:27 > 0:47:29At least some of the bats have made it.
0:47:31 > 0:47:34It's a tremendous relief for Rodrigo.
0:47:41 > 0:47:44Now the mothers have left the cave to find food,
0:47:44 > 0:47:47it's safe for Rodrigo to go inside.
0:47:55 > 0:47:58They turn on their UV torches,
0:47:58 > 0:48:01and carefully comb the cave.
0:48:06 > 0:48:07Ah!
0:48:09 > 0:48:10Blue poop.
0:48:12 > 0:48:17This is proof that these bats are really long distance fliers
0:48:17 > 0:48:23doing 50km one-way trips, and then coming back every night.
0:48:23 > 0:48:26This is a really good find - confirmation.
0:48:28 > 0:48:32To fly to the cactus where Rodrigo dusted it and back
0:48:32 > 0:48:35is a 100-kilometre round trip.
0:48:35 > 0:48:38No-one suspected the bats could fly so far.
0:48:39 > 0:48:43This is a spotted skunk, and it's coming out now.
0:48:43 > 0:48:45I have never seen it before.
0:48:45 > 0:48:50Look at the incredible pattern and a huge feathered plume,
0:48:50 > 0:48:54advertising that it is about to spray us,
0:48:54 > 0:48:58but it chooses to move off into the dark.
0:49:03 > 0:49:08Rodrigo moves far deeper into the maze of the volcano
0:49:08 > 0:49:09than he's ever been before.
0:49:13 > 0:49:16We can check on the reproductive success
0:49:16 > 0:49:21by gauging how many babies are hanging from the roof of a cave.
0:49:29 > 0:49:33At last - far below the desert surface -
0:49:33 > 0:49:37the bats' secret, their nursery.
0:49:40 > 0:49:43This is a group of babies,
0:49:43 > 0:49:48and there's a mix in their ages.
0:49:48 > 0:49:51Most of them are about a week old.
0:49:51 > 0:49:53Very few are one-day-old
0:49:53 > 0:49:57and two-day-old babies. It's always good to see them.
0:50:00 > 0:50:04These are the first babies to be born of what will hopefully
0:50:04 > 0:50:07be hundreds of thousands.
0:50:07 > 0:50:11The future of the entire species hangs in this cave.
0:50:14 > 0:50:20They synchronise their births so that everything happens
0:50:20 > 0:50:25in the space of two weeks, three weeks - that's it.
0:50:27 > 0:50:32You have twice that many bats in there.
0:50:32 > 0:50:34This is...this is huge.
0:50:45 > 0:50:48Oh, yeah, this is a good spot for the camera.
0:50:51 > 0:50:54Rodrigo sets up remote cameras.
0:50:54 > 0:50:56He can't stay when the mothers return,
0:50:56 > 0:50:59so he's never seen what happens here during the day
0:50:59 > 0:51:02when they're reunited with their pups.
0:51:07 > 0:51:12This is a very young baby - one-day-old, two-day-old.
0:51:12 > 0:51:17This is not a good place for the mother to leave this baby.
0:51:19 > 0:51:23The pup is so young, its umbilical cord is still attached.
0:51:23 > 0:51:27It's yet to grow the fur and fat that will keep it warm.
0:51:27 > 0:51:29These babies are tiny.
0:51:29 > 0:51:33At this age, they cannot keep their temperature up.
0:51:33 > 0:51:39They have to be surrounded by dozens or hundreds of other babies
0:51:39 > 0:51:44so that they keep the heat in place in what we call nurseries.
0:51:44 > 0:51:47But this poor guy is here by himself.
0:51:47 > 0:51:50If his mother doesn't come soon,
0:51:50 > 0:51:53his temperature is going to drop and he is going to be in trouble.
0:51:55 > 0:51:58Death is always part of the natural history of these species,
0:51:58 > 0:52:03but I always worry about the fate of these little guys.
0:52:03 > 0:52:05Soon the mothers will start to return
0:52:05 > 0:52:08from across the great desert wastes.
0:52:08 > 0:52:10It's time for Rodrigo to leave.
0:52:18 > 0:52:23In the hours before dawn, the bats flood into the ancient volcano,
0:52:23 > 0:52:25like an eruption in reverse.
0:52:32 > 0:52:35As the day passes on the desert surface,
0:52:35 > 0:52:39the cameras record the bats' hidden lives deep underground.
0:52:43 > 0:52:47At nightfall, once the females have left again,
0:52:47 > 0:52:49they can retrieve the footage.
0:52:50 > 0:52:54It's a long night watching through the many hours recorded.
0:52:56 > 0:53:00This is er...this has to be at around 7 or 8pm.
0:53:02 > 0:53:07Nobody has ever seen a nursery in the process of building up
0:53:07 > 0:53:11the numbers of babies that are being left behind by the mothers.
0:53:13 > 0:53:16- But she's pregnant, right? - Not this one?- No, this one.
0:53:16 > 0:53:18And then...
0:53:18 > 0:53:20Look at this!
0:53:20 > 0:53:24- Having a baby! - Having a...she's having a baby!
0:53:31 > 0:53:33No es possible!
0:53:38 > 0:53:40The baby is coming out!
0:53:40 > 0:53:43THEY SPEAK SPANISH
0:53:43 > 0:53:45This is incredible.
0:53:47 > 0:53:53She's licking, scratching, and again.
0:53:54 > 0:53:55Wow!
0:53:59 > 0:54:04The camera has captured something never seen before.
0:54:04 > 0:54:08- Look at the tiny forearm! - The face - this is the face!- Yes!
0:54:09 > 0:54:13First its head, then its wing emerges.
0:54:13 > 0:54:17Then suddenly, the baby is out and clinging to its mother.
0:54:20 > 0:54:22The wings are protecting the baby,
0:54:22 > 0:54:25so nobody can come close to the baby at all.
0:54:25 > 0:54:27We catch a glimpse of the newborn pup's face
0:54:27 > 0:54:30as its mother cleans it in her fingertips.
0:54:30 > 0:54:35Look at that! Ooh! Baby was slipping away from the mother.
0:54:35 > 0:54:38The baby must be very, very slippery
0:54:38 > 0:54:42and it's slipping down away from the control of the mother,
0:54:42 > 0:54:45so she catches it with the wing.
0:54:45 > 0:54:48The mother quickly positions the baby on her teat
0:54:48 > 0:54:50for its first feed of her milk.
0:54:52 > 0:54:53That is amazing.
0:54:55 > 0:54:59There's a few mothers. There's one, two, three, four.
0:54:59 > 0:55:01But this is all babies.
0:55:01 > 0:55:04Over the next few days, the colony swells
0:55:04 > 0:55:08with thousands upon thousands of new babies.
0:55:08 > 0:55:11This is the flagship colony that is helping me understand
0:55:11 > 0:55:16what is the actual conservation status of that species.
0:55:16 > 0:55:21If we multiply that one birth hundreds of thousands of times,
0:55:21 > 0:55:24tells me that the species has recovered.
0:55:28 > 0:55:32Rodrigo could never have dreamed 20 years ago
0:55:32 > 0:55:34that he'd be seeing such a recovery.
0:55:35 > 0:55:39His tequila bats have come home to roost.
0:55:43 > 0:55:46Our work as conservation professionals
0:55:46 > 0:55:50is not to put as many species as we can
0:55:50 > 0:55:52in endangered species lists.
0:55:54 > 0:55:58Our work is to work as hard as we can
0:55:58 > 0:56:00for as long as is needed -
0:56:00 > 0:56:04as long as is needed only - to recover that species.
0:56:06 > 0:56:11Finally, Rodrigo is ready to make an extraordinary announcement.
0:56:11 > 0:56:15There's places where I have to be in big meetings.
0:56:15 > 0:56:17You have to address the world.
0:56:17 > 0:56:21Before that happens, I picture myself in a cave,
0:56:21 > 0:56:26in the darkness, in the quiet, in the peace of a cave.
0:56:26 > 0:56:27Everything is great then.
0:56:31 > 0:56:34At the Ministry of the Environment in Mexico City,
0:56:34 > 0:56:38journalists and ministers pack the room to hear what he has to say.
0:56:38 > 0:56:39APPLAUSE
0:56:40 > 0:56:48HE SPEAKS SPANISH
0:56:54 > 0:56:57Thanks to the work of Rodrigo, his team,
0:56:57 > 0:57:02and hundreds of others across this country, the lesser long-nosed bat
0:57:02 > 0:57:04is the first species in Mexico
0:57:04 > 0:57:07to be officially saved from extinction,
0:57:07 > 0:57:11and it will be removed from the endangered species list.
0:57:11 > 0:57:17This is a clear indication that our work is actually having
0:57:17 > 0:57:18a good impact in the world.
0:57:20 > 0:57:25His method of combining research, law and community education
0:57:25 > 0:57:29has meant every single bat colony has either stabilised or increased.
0:57:31 > 0:57:35His techniques are now being applied with further success
0:57:35 > 0:57:37to save endangered species of all kinds
0:57:37 > 0:57:40across Latin America and the world.
0:57:41 > 0:57:45Rodrigo really is the bat man.
0:57:46 > 0:57:51This is a great day for the lesser long-nosed bat.
0:57:51 > 0:57:54There's a lot of work to be done
0:57:54 > 0:57:57but first, it's time to celebrate.