0:00:05 > 0:00:07In the heart of the Americas,
0:00:07 > 0:00:11where continents collide,
0:00:11 > 0:00:14there's a land full of natural riches.
0:00:34 > 0:00:36A land of towering giants...
0:00:39 > 0:00:41..scorching sands...
0:00:44 > 0:00:46..and secret rivers.
0:00:53 > 0:00:55Where great civilisations rose...
0:00:57 > 0:00:58..and fell.
0:01:03 > 0:01:06To succeed here takes passion and spirit.
0:01:12 > 0:01:16This is a country rich in colour and culture.
0:01:20 > 0:01:23A festival of life.
0:01:34 > 0:01:36This is Mexico.
0:02:05 > 0:02:10Just south of the American border is a little-known world...
0:02:14 > 0:02:17..Northern Mexico's prairie lands.
0:02:32 > 0:02:34These dry grasslands are home
0:02:34 > 0:02:37to one of Mexico's most sociable animals...
0:02:41 > 0:02:43..the black-tailed prairie dog.
0:02:48 > 0:02:53They live in extensive colonies comprised of dozens of families,
0:02:53 > 0:02:56each with a dominant male, several females
0:02:56 > 0:02:58and their offspring.
0:03:03 > 0:03:07In May, their six-week-old pups take their first steps above ground.
0:03:26 > 0:03:29Grasses and other prairie plants provide all the food
0:03:29 > 0:03:31and moisture these vegetarians need.
0:03:33 > 0:03:36But feeding in this open terrain
0:03:36 > 0:03:37comes with risks.
0:03:57 > 0:04:00Their burrows offer an escape from birds of prey
0:04:00 > 0:04:03and coyotes.
0:04:08 > 0:04:11But they're no protection
0:04:11 > 0:04:14from one of the prairie's most persistent hunters...
0:04:17 > 0:04:20..the bullsnake.
0:04:27 > 0:04:30This powerful constrictor could easily
0:04:30 > 0:04:32suffocate an adult prairie dog.
0:04:32 > 0:04:34PRAIRIE DOG SQUEAKS
0:04:37 > 0:04:39But it's pups he's after.
0:04:48 > 0:04:51And they are hiding somewhere in their burrow.
0:05:04 > 0:05:06PRAIRIE DOG SQUEALS
0:05:06 > 0:05:10Their father would be foolhardy to follow this predator underground.
0:05:29 > 0:05:32The snake's found nothing down this hole,
0:05:32 > 0:05:35so he's on to the next.
0:05:41 > 0:05:46To save his pups, their father must somehow drive the snake away.
0:06:08 > 0:06:10PRAIRE DOG CALLS
0:06:10 > 0:06:13He stands to warn others where the snake is.
0:06:16 > 0:06:19Repeated strikes may just drive it away.
0:06:24 > 0:06:26PRAIRIE DOG CALLS
0:06:38 > 0:06:41The snake concedes defeat.
0:06:47 > 0:06:50On the open prairies, there's safety in numbers
0:06:50 > 0:06:52in this prairie-dog town.
0:06:56 > 0:06:58Thanks to their father's bravery,
0:06:58 > 0:07:00the pups are safe again.
0:07:09 > 0:07:12Northern Mexico sits at a latitude
0:07:12 > 0:07:15where high atmospheric pressure dominates.
0:07:15 > 0:07:17A little rain ever falls.
0:07:19 > 0:07:22This is Mexico's driest region.
0:07:22 > 0:07:25Much of it is desert.
0:07:30 > 0:07:34It's the least populated, wildest corner of the country.
0:07:39 > 0:07:43Journey west and conditions only get hotter,
0:07:43 > 0:07:45drier and more challenging.
0:07:50 > 0:07:55But for those who overcome these conditions,
0:07:55 > 0:07:58there are rich rewards...
0:08:00 > 0:08:04..especially on Mexico's northern prairies.
0:08:05 > 0:08:09THUNDER
0:08:11 > 0:08:13Lying in the foothills of mountains,
0:08:13 > 0:08:17at an altitude of over 5,000 feet,
0:08:17 > 0:08:21these grasslands catch a little more rain than most of the north.
0:08:32 > 0:08:35Between June and September,
0:08:35 > 0:08:39monsoon storms roll in off the Caribbean,
0:08:39 > 0:08:41helping grass to grow.
0:08:48 > 0:08:53For the rest of the year, little, if any, rain falls.
0:08:57 > 0:09:00But even during drought, there is water here.
0:09:06 > 0:09:08Deep underground,
0:09:08 > 0:09:12great reservoirs are trapped in the porous limestone bedrock.
0:09:18 > 0:09:20These giant aquifers help support
0:09:20 > 0:09:24one of Mexico's most iconic ways of life.
0:09:24 > 0:09:26INDISTINCT SHOUTS
0:09:29 > 0:09:30HORSE WHINNIES
0:09:30 > 0:09:33This is cowboy country.
0:09:39 > 0:09:43With year-round water and plenty of pasture,
0:09:43 > 0:09:46these prairies are ideal for cattle ranching.
0:09:51 > 0:09:55For centuries, people like Servando Diaz Gomez
0:09:55 > 0:09:57have worked this land.
0:10:20 > 0:10:24Cowboys are rooted in American culture,
0:10:24 > 0:10:28but their true birthplace is here in the prairies of Northern Mexico.
0:10:38 > 0:10:40In the 16th century, the Spanish
0:10:40 > 0:10:43brought cattle and horses to the north,
0:10:43 > 0:10:46and trained locals to manage their herds.
0:10:52 > 0:10:56The vaquero, or cowboy, was born.
0:11:27 > 0:11:30But the dry conditions make ranching tough.
0:11:33 > 0:11:35These grasses are easily overgrazed.
0:11:37 > 0:11:39Over the last 100 years,
0:11:39 > 0:11:43farming and drought have damaged over half of the prairies.
0:11:51 > 0:11:54But Servando is one of a pioneering band
0:11:54 > 0:11:56trying to reverse this trend.
0:11:59 > 0:12:01Using electric fences,
0:12:01 > 0:12:04he confines his herd to small blocks of pasture.
0:12:09 > 0:12:13Every few hours, they're moved on to the next block.
0:12:18 > 0:12:21The grazed area is then left to recover.
0:12:26 > 0:12:29It's a practice that's having a big impact.
0:12:35 > 0:12:39This healthy pasture is helping Servando rear twice as many cattle.
0:12:42 > 0:12:44And wildlife is thriving.
0:12:51 > 0:12:56Well-managed prairies offer a rich diet of insects and seeds
0:12:56 > 0:12:59for up to three times as many grassland birds.
0:13:04 > 0:13:08And they provide food for one of Mexico's rarest creatures...
0:13:14 > 0:13:16..the aplomado falcon.
0:13:20 > 0:13:23They range as far south as Argentina,
0:13:23 > 0:13:27but Mexico's prairies are their northern limit,
0:13:27 > 0:13:30where only a handful survive.
0:13:33 > 0:13:35Like its relative, the peregrine,
0:13:35 > 0:13:38it specialises in aerial assault.
0:13:54 > 0:13:57The falcon is much faster in level flight.
0:14:03 > 0:14:06But its prey is far quicker on the turn.
0:14:23 > 0:14:27Only one in five pursuits ends in success.
0:14:28 > 0:14:31But aplomado falcons have a secret weapon...
0:14:36 > 0:14:38..breeding pairs hunt together.
0:15:08 > 0:15:12Their prey's only chance to escape is to hide.
0:15:24 > 0:15:29The falcons need to flush the bird out...
0:15:33 > 0:15:36..and two birds are better than one.
0:16:03 > 0:16:06Working together, these birds are twice as successful.
0:16:08 > 0:16:11And every catch is vital when you're raising a family.
0:16:14 > 0:16:17Conservationists have put up platforms
0:16:17 > 0:16:21to protect the precious chicks from ravens and owls.
0:16:22 > 0:16:25Precious because they are so rare.
0:16:30 > 0:16:34There are only five pairs here,
0:16:34 > 0:16:38and these are the only ones to successfully breed this year.
0:16:43 > 0:16:46But with conservationists and ranchers
0:16:46 > 0:16:49looking out for these spectacular birds,
0:16:49 > 0:16:51they've hopefully got a brighter future.
0:16:55 > 0:16:59Teamwork is important for many in Mexico's prairies.
0:17:03 > 0:17:05So, too, is bravery.
0:17:34 > 0:17:37Charros are traditionally dressed cowboys
0:17:37 > 0:17:40who compete in Mexico's official national sport...
0:17:45 > 0:17:47..the charreria.
0:17:55 > 0:17:58What was once a friendly competition between neighbours
0:17:58 > 0:18:00hundreds of years ago
0:18:00 > 0:18:05is now the ultimate display of cowboy bravado.
0:18:19 > 0:18:22Each team of charros is made up of specialists
0:18:22 > 0:18:25who perform nine different equestrian events across the day...
0:18:27 > 0:18:29..that showcase all the cattle handling,
0:18:29 > 0:18:33riding and roping skills used in cowboy life.
0:18:36 > 0:18:39The most dangerous is saved until last.
0:18:44 > 0:18:48Martin specialises in el paso de la muerte...
0:18:52 > 0:18:55..the pass of death.
0:18:58 > 0:19:00Galloping at full speed,
0:19:00 > 0:19:04he has to jump onto the back of a wild, untamed horse
0:19:04 > 0:19:06and hang on without reins.
0:19:13 > 0:19:15If he falls, he'll be trampled.
0:19:26 > 0:19:31Martin now risks everything to secure victory for his team.
0:20:27 > 0:20:30In the burning north, success favours the brave.
0:20:41 > 0:20:46Mexico's prairies run along the edge of great mountain ranges -
0:20:46 > 0:20:50the Western and Eastern Sierra Madres.
0:20:54 > 0:20:57Over 10,000 feet high,
0:20:57 > 0:21:00they intercept moist air coming from the Pacific Ocean
0:21:00 > 0:21:01and Gulf of Mexico.
0:21:06 > 0:21:10Beyond the prairies, the land is starved of rain...
0:21:13 > 0:21:17..creating one of the biggest deserts in North America.
0:21:22 > 0:21:25The Chihuahuan Desert.
0:21:29 > 0:21:31It covers an area larger than Britain...
0:21:33 > 0:21:37..and receives about half as much rain as the prairies.
0:21:43 > 0:21:46But in the heart of this desert
0:21:46 > 0:21:49is one of Mexico's greatest natural wonders...
0:21:51 > 0:21:54..the valley of Cuatro Cienegas.
0:22:02 > 0:22:04It may look barren...
0:22:07 > 0:22:10..but this valley hides an oasis.
0:22:37 > 0:22:40Here, aquifers break the surface,
0:22:40 > 0:22:42creating a water world.
0:22:47 > 0:22:50Most of these pools, known locally as pozas,
0:22:50 > 0:22:53are fed by thermal springs,
0:22:53 > 0:22:58where underground water is forced to the surface by geothermal heat.
0:23:03 > 0:23:06Millions of years ago,
0:23:06 > 0:23:08when this region was much wetter,
0:23:08 > 0:23:11ancient waterways brought fish into this valley.
0:23:15 > 0:23:18As the climate dried, the waters receded,
0:23:18 > 0:23:21and fish became isolated in pools,
0:23:21 > 0:23:24evolving into many new species.
0:23:30 > 0:23:3416 species live here,
0:23:34 > 0:23:37half of them found nowhere else on Earth.
0:23:41 > 0:23:44Including this one,
0:23:44 > 0:23:47a Cuatro Cienegas cichlid.
0:23:53 > 0:23:56This female has a family...
0:23:58 > 0:24:02..and she is the most devoted mother.
0:24:07 > 0:24:09Stirring up the sediment,
0:24:09 > 0:24:13she exposes tiny plankton for her fry to feed on.
0:24:18 > 0:24:23But the biggest challenge isn't feeding her babies,
0:24:23 > 0:24:26it's protecting them.
0:24:35 > 0:24:38Some cichlids have evolved into predators...
0:24:43 > 0:24:46..and in this small pool there are few places to hide.
0:25:05 > 0:25:09From dawn until dusk, she must defend her brood.
0:25:13 > 0:25:16She has no time to feed herself,
0:25:16 > 0:25:19and is getting weaker by the day.
0:25:26 > 0:25:27But it's worth it.
0:25:27 > 0:25:32Without her help, her young would never survive.
0:25:36 > 0:25:38When they're a centimetre long,
0:25:38 > 0:25:40they will fend for themselves.
0:25:42 > 0:25:46Until then, this mother must give her all.
0:25:51 > 0:25:53An astonishing diversity of life
0:25:53 > 0:25:55has evolved in this valley.
0:25:57 > 0:26:00It's home to more unique species
0:26:00 > 0:26:03than anywhere else on the North American continent.
0:26:05 > 0:26:08That's the exception to the norm.
0:26:16 > 0:26:19Most of this great desert is dominated
0:26:19 > 0:26:21by just a few hardy souls.
0:26:23 > 0:26:26And one plant copes better than most...
0:26:32 > 0:26:34..the creosote bush -
0:26:34 > 0:26:38so-called because it smells like wood preservative.
0:26:43 > 0:26:46Locals call it la gobernadora -
0:26:46 > 0:26:48the governess.
0:26:48 > 0:26:52And it governs for a very long time.
0:26:57 > 0:26:59One plant is known to have survived
0:26:59 > 0:27:03for over 11,000 years.
0:27:08 > 0:27:10It's brilliant at coping with drought.
0:27:13 > 0:27:15Tiny, resin-coated leaves
0:27:15 > 0:27:19drastically reduce water loss.
0:27:22 > 0:27:26And its shallow roots quickly soak up any moisture...
0:27:28 > 0:27:30..stopping anything growing in between.
0:27:39 > 0:27:42Creosote has truly conquered this desert.
0:27:46 > 0:27:50Its success has been exploited by a creature
0:27:50 > 0:27:52that's addicted to creosote...
0:27:52 > 0:27:55CHIRPING SOUNDS
0:28:05 > 0:28:07..the creosote bush grasshopper.
0:28:13 > 0:28:17It's one of the few animals that can stomach this plant.
0:28:20 > 0:28:24It's resinous leaves are indigestible to most animals,
0:28:24 > 0:28:28but this grasshopper eats nothing else.
0:28:29 > 0:28:32It's even evolved to look like this plant
0:28:32 > 0:28:34to avoid becoming food itself.
0:28:39 > 0:28:43Most of the bushes have their own resident male.
0:28:43 > 0:28:45GRASSHOPPERS CHIRP
0:28:46 > 0:28:50Their calls let other males know this bush is occupied.
0:28:54 > 0:28:57They're also very attractive to the opposite sex.
0:29:03 > 0:29:07This newly-arrived female is exactly what he's been waiting for.
0:29:14 > 0:29:16But they are not alone for long.
0:29:16 > 0:29:18Another male flies in.
0:29:23 > 0:29:26A female is worth fighting for.
0:29:34 > 0:29:37He must throw his rival out of his bush.
0:29:55 > 0:29:58Easier said than done with so many legs.
0:30:10 > 0:30:13Victory for the resident male.
0:30:21 > 0:30:26But he's just one of millions of battling grasshoppers
0:30:26 > 0:30:29in this endless expanse of creosote.
0:30:29 > 0:30:32GRASSHOPPERS CHIRP
0:30:41 > 0:30:44Hundreds of miles to the west,
0:30:44 > 0:30:47the vast Chihuahuan Desert meets great mountains.
0:30:54 > 0:30:59These high sierras catch more rain than the desert below,
0:30:59 > 0:31:01enabling forests to grow.
0:31:04 > 0:31:07Offering a refuge for a special plant
0:31:07 > 0:31:10with the hottest reputation.
0:31:10 > 0:31:13THEY SPEAK SPANISH
0:31:16 > 0:31:19Every autumn, Armida Elena Contreras Duron
0:31:19 > 0:31:24and her husband Eliazar head out to their mountain ranch
0:31:24 > 0:31:27to pick wild chillies called chiltepin.
0:31:47 > 0:31:50These plants might have a fiery nature,
0:31:50 > 0:31:53but they can be remarkably delicate.
0:31:53 > 0:31:56They don't like constant exposure to the desert sun.
0:31:59 > 0:32:03But this woodland provides enough shade for them to thrive.
0:32:11 > 0:32:156,000 years ago, this wild plant started a food revolution
0:32:15 > 0:32:19when it was first domesticated here in Mexico.
0:32:22 > 0:32:26It's given rise to thousands of varieties of chillies worldwide.
0:32:27 > 0:32:31And with fruit 20 times hotter than jalapenos,
0:32:31 > 0:32:34it gives a spectacular kick to Armida's cuisine.
0:33:04 > 0:33:07And an awful lot of chillies.
0:33:13 > 0:33:17Every type of chilli has a unique flavour.
0:33:17 > 0:33:19Chiltepins are particularly cherished
0:33:19 > 0:33:22because they are arrebatado,
0:33:22 > 0:33:25meaning rapid, or violent.
0:33:25 > 0:33:30They're hot, but their heat subsides quickly, and that's addictive.
0:33:48 > 0:33:52To Armida and her family, it's part of their national identity.
0:34:04 > 0:34:07These mountain forests are one of the few places
0:34:07 > 0:34:10where wild chiltepin thrive.
0:34:10 > 0:34:13And because of our love of this spicy plant,
0:34:13 > 0:34:17its descendants have spread all around the world.
0:34:35 > 0:34:37In the foothills to the west,
0:34:37 > 0:34:40the sun has shaped another desert
0:34:40 > 0:34:42that couldn't look more different.
0:34:49 > 0:34:54Stretching over 100,000 square miles,
0:34:54 > 0:34:58the Sonoran Desert covers much of Northwest Mexico.
0:35:06 > 0:35:10And it's home to the most iconic desert plant of all...
0:35:14 > 0:35:17..the saguaro cactus.
0:35:23 > 0:35:27The Sonoran Desert is hotter and drier than the Chihuahuan.
0:35:31 > 0:35:34And one way to cope is to become gigantic.
0:35:42 > 0:35:45Towering up to 18 metres,
0:35:45 > 0:35:48saguaros can store great reserves of water.
0:35:51 > 0:35:53THUNDER
0:36:01 > 0:36:06During summer storms, a season's rain can fall in just a few hours.
0:36:12 > 0:36:16The saguaro is built to take advantage of this.
0:36:16 > 0:36:20Its shallow roots stretch as wide as the cactus is tall,
0:36:20 > 0:36:25and its split trunk allows it to expand like an accordion,
0:36:25 > 0:36:27enabling the largest cacti
0:36:27 > 0:36:30to absorb one tonne of water during one storm.
0:36:38 > 0:36:41It's enough water to last for a year,
0:36:41 > 0:36:45making saguaros the lifeblood of this desert.
0:36:53 > 0:36:56Even in a drought year, saguaros bloom.
0:36:56 > 0:36:59They're a magnet for wildlife.
0:37:11 > 0:37:15Almost every creature here relies on this plant,
0:37:15 > 0:37:18and not just as a source of food and moisture.
0:37:28 > 0:37:32Most of the older cacti are pockmarked with nest holes...
0:37:34 > 0:37:37..excavated by Gila woodpeckers.
0:37:44 > 0:37:46But squatters often move in.
0:37:48 > 0:37:50In this world of giants,
0:37:50 > 0:37:52it helps to be tiny.
0:37:56 > 0:37:59Not much bigger than a sparrow,
0:37:59 > 0:38:03ferruginous pygmy owls easily squeeze into woodpecker holes.
0:38:06 > 0:38:09And this female has a family to feed.
0:38:19 > 0:38:22Deep inside, chicks are safe.
0:38:24 > 0:38:27And not just from predators.
0:38:29 > 0:38:32Outside is 40 degrees...
0:38:39 > 0:38:42..but this plant's enormous stores of water
0:38:42 > 0:38:45keep the interior up to eight degrees cooler
0:38:45 > 0:38:47than the surroundings.
0:38:56 > 0:38:59A vital refuge for a family of tiny owls
0:38:59 > 0:39:02in the crippling heat of the day.
0:39:14 > 0:39:20At night, the daytime heat is lost to the heavens.
0:39:29 > 0:39:33With such clear skies and no light pollution,
0:39:33 > 0:39:37Northern Mexico is one of the best places on Earth
0:39:37 > 0:39:39to stargaze.
0:39:51 > 0:39:56Under the cooler conditions, the desert comes alive.
0:40:00 > 0:40:03Many animals switch to a night routine
0:40:03 > 0:40:05to avoid the heat of the day.
0:40:14 > 0:40:18Including one of Mexico's most infamous residents.
0:40:22 > 0:40:24The scorpion.
0:40:28 > 0:40:34Mexico is home to the greatest diversity of scorpions on Earth
0:40:34 > 0:40:37and the Sonoran Desert is a stronghold.
0:40:46 > 0:40:50But even fearsome predators must tread carefully.
0:40:51 > 0:40:54Others are listening in.
0:41:01 > 0:41:06In the desert, you've got to grab any opportunity for a meal,
0:41:06 > 0:41:08no matter how dangerous.
0:41:12 > 0:41:17Pallid bats have become scorpion-hunting specialists.
0:41:30 > 0:41:34Their large ears are especially sensitive,
0:41:34 > 0:41:38capable of hearing the footsteps of their prey.
0:41:46 > 0:41:50As long as this scorpion stays still, it's safe.
0:41:53 > 0:41:57But this bat has another way of increasing its chances.
0:42:04 > 0:42:06It stalks its prey.
0:42:17 > 0:42:21The slightest flinch will give the scorpion away.
0:42:50 > 0:42:52Its sting is no defence.
0:42:52 > 0:42:56Pallid bats are immune to scorpion venom.
0:43:00 > 0:43:05By learning how to hunt one of the desert's most common creatures,
0:43:05 > 0:43:08these bats have found a unique way to prosper
0:43:08 > 0:43:10in this difficult environment.
0:43:14 > 0:43:16It's a big meal, too,
0:43:16 > 0:43:19and a vital source of moisture in such a dry place.
0:43:37 > 0:43:41On the western edge of the Sonoran Desert,
0:43:41 > 0:43:44daytime conditions couldn't be more extreme.
0:43:49 > 0:43:51This is El Pinacate.
0:43:52 > 0:43:55A landscape with a violent past.
0:43:55 > 0:44:01Pitted with volcanic craters and extensive lava flows.
0:44:04 > 0:44:08Temperatures can reach 56 Celsius.
0:44:10 > 0:44:12Years can pass without rain.
0:44:18 > 0:44:22In 1970, astronauts on the Apollo 14 mission
0:44:22 > 0:44:26came here to test their lunar equipment...
0:44:34 > 0:44:37..because the conditions have created a moonscape.
0:44:46 > 0:44:50This is Mexico's driest region.
0:44:56 > 0:45:01All the more surprising as it borders the sea.
0:45:11 > 0:45:14The Sonoran Desert stretches for hundreds of miles along
0:45:14 > 0:45:17Mexico's Pacific coast
0:45:17 > 0:45:19and the Gulf of California.
0:45:23 > 0:45:27These waters have helped shape this parched coastline.
0:45:31 > 0:45:34Fed by the cold Californian current,
0:45:34 > 0:45:38these seas produce cool and dry onshore winds,
0:45:38 > 0:45:40starving the land of moisture.
0:45:43 > 0:45:45Clouds struggle to form...
0:45:48 > 0:45:52..creating a coastal desert that extends far out to sea.
0:46:07 > 0:46:11In the most isolated corner of the Gulf of California
0:46:11 > 0:46:13is a true desert island.
0:46:19 > 0:46:22Isla San Pedro Martir.
0:46:29 > 0:46:33Giant cardon cacti are one of the few things that can withstand
0:46:33 > 0:46:36the drought-ravaged conditions.
0:46:42 > 0:46:44There's no fresh water...
0:46:45 > 0:46:48..and few obvious opportunities for a meal.
0:46:54 > 0:46:58But it's home to an especially resilient resident.
0:47:02 > 0:47:05The side-blotched lizard.
0:47:07 > 0:47:11Endemic to this island, it's ancestors became isolated on this
0:47:11 > 0:47:15barren outcrop seven million years ago.
0:47:25 > 0:47:31Being marooned would have been a death sentence for most creatures,
0:47:31 > 0:47:36but this stowaway has made a remarkable success of being stranded...
0:47:38 > 0:47:41..because of a banquet found just offshore.
0:48:01 > 0:48:04The cold seas that created this desert island are some of
0:48:04 > 0:48:06the richest on earth.
0:48:10 > 0:48:15Nutrient-rich waters are forced to the surface around islands like
0:48:15 > 0:48:17Isla San Pedro Martir,
0:48:17 > 0:48:20fuelling an explosion of marine life.
0:48:41 > 0:48:45In May, the island is transformed into one of the world's largest
0:48:45 > 0:48:48breeding colonies of this aptly-named bird...
0:48:50 > 0:48:52..the blue-footed booby.
0:48:55 > 0:48:59It's the lifeline this lizard has been waiting months for.
0:49:04 > 0:49:07Raising a family is a messy affair.
0:49:11 > 0:49:13Nests are littered with leftovers.
0:49:16 > 0:49:19And this lizard has learned to eat fish.
0:49:31 > 0:49:35But to secure a meal, it has to be quick,
0:49:35 > 0:49:37there's an awful lot of competition.
0:49:52 > 0:49:56These birds have had an extraordinary impact on the lizards
0:49:56 > 0:49:57isolated on this island.
0:50:03 > 0:50:07With so few species to share this unusual bounty,
0:50:07 > 0:50:10they have completely overrun this place.
0:50:25 > 0:50:28This island has one of the world's highest densities of lizards...
0:50:30 > 0:50:33..over 30 times more than the Mexican mainland.
0:50:37 > 0:50:42They are the ultimate proof that even the most barren places
0:50:42 > 0:50:43can be bountiful.
0:50:46 > 0:50:48If you can find a way,
0:50:48 > 0:50:53you really can thrive in Mexico's burning north.
0:50:58 > 0:51:02Mexico is blessed with an astonishing diversity of life.
0:51:03 > 0:51:05A country bursting with colour...
0:51:08 > 0:51:11..and the richest natural heritage...
0:51:14 > 0:51:20..with a spirit and vibrancy found nowhere else on Earth.
0:51:34 > 0:51:36In making this episode,
0:51:36 > 0:51:39the crew travelled to some of Mexico's remotest regions,
0:51:39 > 0:51:42capturing remarkable animal behaviour in the wild.
0:51:44 > 0:51:49But there was one exception - pallid bats.
0:51:49 > 0:51:52They cover many miles of desert every night
0:51:52 > 0:51:55hunting scorpions in the pitch-black -
0:51:55 > 0:51:58impossible to film under natural conditions.
0:52:00 > 0:52:03So the crew teamed up with bat scientist Winifred Frick,
0:52:03 > 0:52:06who studies how these bats feed in captivity.
0:52:08 > 0:52:12With her help, they brought the desert into a special bat lab
0:52:12 > 0:52:15to hopefully film this rarely-seen behaviour.
0:52:18 > 0:52:22This makeshift lab on the Baja Peninsula may not be remote,
0:52:22 > 0:52:27but it's still presents problems for cameraman Luke Barnett.
0:52:27 > 0:52:31It's dark, it's 40 degrees, stuff keeps not working
0:52:31 > 0:52:35and power supplies keep packing up, so it's going to be a challenge.
0:52:37 > 0:52:40While the finishing touches are put to the set,
0:52:40 > 0:52:45Winifred is looking after the stars of the show backstage.
0:52:45 > 0:52:46I just think they're beautiful.
0:52:46 > 0:52:50They've got these big ears, they have this...almost this little
0:52:50 > 0:52:54piggy snout, they've just got a lot of character to their face.
0:52:55 > 0:52:58For her studies, Winifred catches wild bats
0:52:58 > 0:53:01which she releases a few weeks later.
0:53:01 > 0:53:05She feeds and weighs them every day to make sure they're healthy.
0:53:08 > 0:53:11To understand their predatory behaviour for scorpions
0:53:11 > 0:53:13and understand... I mean, scorpions, they eat,
0:53:13 > 0:53:16we have to bring them into the flight cage because
0:53:16 > 0:53:18you can't record that in the wild
0:53:18 > 0:53:20because we don't know where a scorpion is going to be
0:53:20 > 0:53:21and when the bat's going to hit it.
0:53:24 > 0:53:28To enter the bat's world, the crew switch to night shifts,
0:53:28 > 0:53:33filming in complete darkness using infrared cameras.
0:53:33 > 0:53:35But will the bats perform?
0:53:48 > 0:53:51Well, it's been quite slow, really,
0:53:51 > 0:53:54cos the bats aren't used to the environment perhaps.
0:53:54 > 0:53:56And the bats are somewhere in the corner.
0:53:56 > 0:53:57I think they're all huddling.
0:53:57 > 0:54:00They've got a better idea, they've gone to sleep.
0:54:00 > 0:54:04Yeah, midnight and we're all a bit tired and a bit hot.
0:54:09 > 0:54:12It ends up being an exhausting
0:54:12 > 0:54:16and fruitless first evening for them all.
0:54:16 > 0:54:20And a quiet few hours soon turns into a quiet few nights.
0:54:24 > 0:54:26Without knowing when a bat might strike,
0:54:26 > 0:54:29Luke and the team must stay alert.
0:54:30 > 0:54:35Easier said than done when working all night in 40-degree heat.
0:54:35 > 0:54:38- We're losing you.- I know.
0:54:40 > 0:54:43The bats are resting. The bat biologist is resting.
0:54:43 > 0:54:47Must be the worst bit about being a bat biologist, not falling asleep.
0:54:47 > 0:54:50- You find it hard?- Yeah.
0:54:50 > 0:54:52Well, it's funny, I'm actually not a night person.
0:54:52 > 0:54:55So my joke is I'm the world's worst bat biologist
0:54:55 > 0:54:57cos I'm also claustrophobic.
0:54:57 > 0:55:00- So not a night person, I don't like to go into caves.- Brilliant.
0:55:05 > 0:55:08It's now just come up to six o'clock in the morning
0:55:08 > 0:55:12and we started about five with great expectations.
0:55:12 > 0:55:13A few came down and circled around,
0:55:13 > 0:55:17but there wasn't a lot going on, so it's very disappointing.
0:55:18 > 0:55:23The bats never go hungry as Winifred feeds them every day.
0:55:23 > 0:55:27But after five frustrating nights, the team needs to rethink.
0:55:27 > 0:55:30A raised set makes filming more manageable,
0:55:30 > 0:55:32but Winifred thinks this is the problem.
0:55:32 > 0:55:34We may have to accommodate them,
0:55:34 > 0:55:37rather than hoping that they're going to accommodate us.
0:55:37 > 0:55:39I think make it work with the cameras and everything,
0:55:39 > 0:55:42trying to get the set down on to the ground level
0:55:42 > 0:55:44- will be the next thing to try.- Sure.
0:55:51 > 0:55:53We've had to lower the set,
0:55:53 > 0:55:56so hopefully now the bats will fly around much more over the top.
0:55:56 > 0:55:59It's not been a job that we really wanted to do
0:55:59 > 0:56:03cos all we want to do is have a cold shower and sleep, so...
0:56:04 > 0:56:07Yeah, another night coming up.
0:56:09 > 0:56:14With a more bat-friendly filming set, there's renewed hope.
0:56:14 > 0:56:15This looks awesome, you guys.
0:56:15 > 0:56:19This looks like exactly where they'd be hunting out in the wild
0:56:19 > 0:56:20and getting it down on the floor.
0:56:20 > 0:56:24I think it's going to be really key. So I feel pumped. This looks good.
0:56:27 > 0:56:29As the bats start to stretch their wings,
0:56:29 > 0:56:32they're already showing a lot more interest.
0:56:33 > 0:56:37And Luke manages to get some great flying shots of these bats
0:56:37 > 0:56:38in hunting mode.
0:56:47 > 0:56:49It was much better today,
0:56:49 > 0:56:53we lowered the set to the floor and it seemed to make a big difference,
0:56:53 > 0:56:56the bats are flying right over the set for a change,
0:56:56 > 0:56:59rather than around the outside, low to the ground, so...
0:56:59 > 0:57:01we're all feeling a bit more excited.
0:57:04 > 0:57:07But Luke still hasn't managed to film the key shot
0:57:07 > 0:57:09of a bat catching a scorpion.
0:57:11 > 0:57:14As wildlife cameramen know only too well,
0:57:14 > 0:57:17capturing behaviour takes patience.
0:57:17 > 0:57:20With only a couple of days of filming left,
0:57:20 > 0:57:22the bats finally settle in.
0:57:29 > 0:57:32- Look at that.- Oh, look at that. He's moved back.- Oh!
0:57:33 > 0:57:37I can't believe... He's just gone again. We just got a shot.
0:57:37 > 0:57:39That is such a relief.
0:57:39 > 0:57:40That makes...
0:57:40 > 0:57:43That makes me happy because it means that at last we've actually got
0:57:43 > 0:57:45what is looking like a sequence.
0:57:45 > 0:57:49Without that moment of capture, we'd have nothing.
0:57:51 > 0:57:55And there's behaviour that Winifred has never seen before.
0:57:55 > 0:57:58When it comes in, it cups it straightaway.
0:57:58 > 0:57:59Yeah.
0:57:59 > 0:58:02Yeah, look, she just makes that awesome tent with her wings
0:58:02 > 0:58:04and her tail.
0:58:04 > 0:58:06And the only way out is teeth.
0:58:08 > 0:58:11We just never get to see this in the wild.
0:58:11 > 0:58:12This is amazing.
0:58:12 > 0:58:14Oh, that is beautiful.
0:58:17 > 0:58:19- Off she goes.- Yeah.
0:58:21 > 0:58:25It's time to take the bats back to their wild desert home.
0:58:28 > 0:58:30There... She's off.
0:58:31 > 0:58:33It's been a unique glimpse into
0:58:33 > 0:58:36the life of one of Mexico's most secretive animals.