Natural World (1983) s24e06 Episode Script

Cuba is a tropical paradise but it's a paradise full of surprises Beyond the cities lives a wild mysterious island teeming with uniquely Cuban animals Each bizarre creature is a story of triumph against staggering odds How did they get here? And how have they survived? Cuba holds many mysteries that are only now being revealed It's a story that stretches back in time beyond the period of human settlement It's a tale of titanic forces, ocean currents, wild storms and an amazing island ark Cuba has a long history From 1492, when Columbus landed through the Spanish colonial period that created so much of old Havana, to modern times of revolution, communism and the rule of Fidel Castro Millions of tourists are drawn to Cuba each year by the attractions of music, cigars and tobacco But beyond the fields, the cities and the beaches lies a wild Cuba a little known world with a much longer but equally colorful and fascinating history We can see part of that history alive and well in the tropical seas that surround Cuba The coral reefs teem with fish They can claim to be the best in the Caribbean and this in part is due to Cuba's recent past For since the revolution in 1959, these seas have had little fishing pressure This reef may look much the same now as it did thousands of years ago and now, as then, there are predators searching for an opportunity The top predator is the Caribbean reef shark A sick fish's only hope of survival is to hide But the sharks can sense weakness They can detect the scent of an ill or bleeding fish from a great distance They home in on the scent and vibrations of the fish The sharks get ever closer now using their electrical sense to pick up the muscle specimens of the ill fish Once the sharks become excited, no fish is safe The seas around Cuba are spectacular in a clarity and a profusion of life they support But the sharks and the coral fishes are not exclusively Cuban for they can be found elsewhere in the Caribbean If you want to see uniquely Cuban wildlife, you need to look back to the land and to understand the nature of Cuba, you must go back in time Cuba's wild history stretches back millions of years During the last Ice Age, much of the world's water was locked up as ice and so the sea level was lower Cuba was a bigger and broader island What are shallow seas today were then lush freshwater swamps These swamps covered much of Cuba, the Bahamas and the Cayman Islands and must have been home to millions of mosquitoes and to a variety of other creatures including this, the Cuban hutia These large rodents can still be found today along with the mosquitoes They tend to stick to the pockets of high ground, avoiding the water and for good reason There's another creature that lives in the swamp Cuban crocodile This crocodile can grow to nearly 13 feet and weigh 280 pounds It has the reputation of being the most aggressive crocodile in the world The Cuban crocodile evolved here about 2 million years ago and it evolved alongside the hutia Occasionally hutias have to venture out to reach better feeding They are neither the most elegant nor efficient of swimmers The commotion alerts the crocodiles Now it's a matter of time Will the hutia reach dry land before the crocodiles reach it? The crocodile evolved to hunt hutias and not just in the water The hutia may appear safe when feeding in the trees but appearances can be deceptive The crocodiles have a fine sense of smell and pick up the scent of a hutia carried on the tropical air Swimming slowly upwind, they home in on the isolated tree from over a mile away The hutia is 6 feet up the tree but this crocodile has a way of reaching its goal The hutia has no way of escape The crocodiles have all the time in the world to improve their high jump performance The leaping crocodiles evolved on Cuba in the swamps that covered vast areas during the Ice Age But the swamps were not always that large As the sea level changed, some wetlands would have been transformed into forests Today, the dry forest is the home of many of the birds of Cuba like the Cuban parrot Birds must have flown to Cuba over a period of millions of years The more recently colonists, like the turkey vulture have remained the same as birds on the American continents Other more ancient arrivals evolved into Caribbean birds found on several of the islands But some birds are wholly Cuban, found nowhere else on earth Their ancestors, typically woodland birds were ideal pioneers They were strong flyers able to reach the island but once there, they stayed put in the forest Over time, these birds changed into uniquely Cuban creatures like the national bird, the Cuban trogon Over many generations, the birds adapted to their island home the process of evolution molding them into their surroundings There were new plants and animals to feed on and new patterns of weather to cope with The climate has an important influence on animals Cuba has distinct wet and dry seasons Many of the birds evolved to breed with the onset of the summer rains The heavy rains stimulate not only the birds This event triggers a wildlife spectacle that begins below on the forest floor The trees grow straight out of the rock This is an old coral reef exposed by the changing levels of the sea and land These crabs evolved about 4 million years ago They are true land creatures but they still breathe using gills like their marine ancestors so they dehydrate easily They time their emergence to the high humidity brought by the rains The males leave the rocky-floored forest and dig a shelter in the soft soil closer to the coast Here they wait for the females The land crabs can range in color from dark red to bright yellow but they are all the same species Some males mate in the shelter other males mate beside their tunnels fending off other interested parties The male's embrace may look gentle but with claws, there's a limit to tenderness Once the sperm is transferred, the crabs separate and the males and females make their way back into the forest At the same time as the female crabs wait for their eggs to develop the Cuban parrots, too, are breeding Parrots pair for life and stay faithful to their patch of dry forest The breeding pairs' needs are simple a good supply of food, a place to lay their eggs Parrots don't make their own nest hole For that, they depend on this curious tree the potbellied palm and the work of the West Indian woodpecker But not all the woodpecker's activities benefit the parrots For the woodpeckers are nest robbers This Cuban drama may have taken place each rainy season for millions of years And the same is true of the land crabs After a few weeks the females reappear carrying their ripe eggs in a pouch Again, the numbers grow as the crabs move once more out of the forest They are headed for the sea, their ancestral home The urge to spawn is so great that nothing stops the migration The crabs climb walls and cross paths They even walk through the grounds of hotels Their journey may be as long as 6 miles and can take several days They need to find shelter during the hottest part of the day if they are not to die of dehydration Trees provide natural cover But today, the crabs can also enjoy the benefits and luxuries provided by tourist hotels They swarm up the windows and crawl under the shutters to avoid the hot ground and direct sun They are quite prepared to share a room with human guests especially if there is air conditioning at night The next morning, the swarm is on the move on the last part of their journey How the crabs know where the coast is and in which direction to move is a mystery The final part is the toughest The sharp pinnacles of an old coral reef are like miniature mountains for the crabs In the cool of the morning, the crabs finally reach their goal They can only spawn when the sea is calm for otherwise they'd risk being washed off the rocks and swept out to sea These are land crabs and they cannot survive in the sea Some are nervous about entering this alien world Others dive right in They shake their precious cargo of eggs into the sea This is their last connection with their ancestral home The eggs hatch immediately and the next generation starts its life in the Caribbean sea The sea becomes a soup of crab larvae and the bounty does not go unnoticed Mullet suck in the eggs But they have no real impact, the numbers are overwhelming For a few weeks, the coastline of the infamous Bay of Pigs is awash with billions of baby crabs Wave after wave arrive at the coast to spawn Every day, new crabs shed their eggs into the Bay of Pigs Once each female's pouch is empty, she heads back to the forest It's on the return journey that the crabs face their greatest danger There are millions of them in this one small area of Cuba This annual spectacle has taken place every year for eons Evolution has hard-wired it into the crabs' brains They know how to find the sea and how to avoid dying from heat and loss of water But evolution could not prepare them for the modern world They have no way to deal with traffic Tourist taxis give the crabs a chance to escape to safety But other traffic is less considerate Instinct tells the crabs that shade of a shelter The result is carnage Nothing in their 4 million year history could prepare them for Russian trucks The dead ones attract other crabs for an easy meal But for many, it's their last The death toll on the roads is huge and attracts vultures This is a time of plenty for them Despite appearances, most crabs survive their dice with death on the road though for some, it's a close shave The walking wounded and survivors head for the side of the road on the safety of the verge on the dry forest beyond They'll not venture out of the forest again until the rains return Living in the same forest is a bird whose ancestors may have arrived on Cuba around the time of the crabs The bee hummingbird It is the smallest bird in the world - 2 inches long That makes it the same size as a dragonfly The male weighs only 500th of an ounce This is half the weight of a penny Yet despite their size, the birds are very aggressive each male defending its territory with song and flashes of iridescence If this fails, the males fly up over 300 feet and then power-dive down on their opponent The males display all day, using large amounts of energy When they power-dive, they reach speeds over 90 miles per hour The wings beat 200 times per second and the heart rate is a staggering 1000 beats per minute The male's display not only drives off intruders, it also attracts females Like the male, she has huge energy needs Whilst incubating, she reduces her body temperature to decrease the time she must leave the eggs unguarded These smallest of birds live on an energy knife-edge A lowered body temperature means less need for food and so the female can return to her nest sooner The male guards his patch of forest, not for the benefit of the female, but for his own For the territory holds his most precious resource: flowers He may sip from as many as 2000 flowers a day to obtain the nectar he needs to fuel his energetic lifestyle The bee hummingbird is a miniature specialist feeding on small flowers that insects normally visit The reason is the ancestors of the bee hummingbird did not have Cuba to themselves They shared the island with another hummingbird and today there are still two species The Cuban emerald is over twice the size of the bee hummingbird but still smaller than a chickadee The Cuban emerald, like the smaller bee hummingbird is found nowhere else on earth The two hummingbirds evolved on Cuba and by becoming different in size, avoided competing with each other Being bigger, the Cuban emerald is more of a generalist and feeds from a wilder range of blossoms They include this curiously shaped flower But this blossom is not designed for hummingbirds The birds are really plundering nectar destined for another creature one that only appears after sunset and then only on the darkest of nights These creatures shun light and can only be recorded by infrared or black light Nectar-feeding bats fly as far as 50 miles in search of food They first detect flowering trees by scent After the initial approach, the bats then use their powers of echolocation The flower's shape reflects a narrow beam of ultrasound back to the bats guiding them to the nectar The bats extract the nectar in less than a second Nectar is a rich source of energy and the bats quickly fill their stomachs and then return to their cave Here, the nectar-feeding bats are not alone for there are over 30 species found on Cuba Like the birds, the different kinds of bats arrived over many millions of years Many of the secrets of Cuba's bats have been discovered by Professor Gilberto Silva He studied them for over 50 years Cuba is largely composed of limestone and is riddled with caves There is a higher density of caves in Cuba than any other place on earth This particular cave is the home to a rather special bat Years ago, when Gilberto first entered its sleeping chamber, he nearly died There was so little oxygen to breathe How the bats survive in their anoxic chamber remains one of Cuba's mysteries Nowadays, Gilberto waits outside for the bats to come to him Like the nectar bats, they are not fly in light Gilberto captures them using the sound of their wings alone Only when safely in the hand can he use a lamp The butterfly bat has that very urban characteristic of being small In fact, it can claim to be the smallest bat in the world Like the diminutive hummingbird, this tiny bat can only be found on Cuba Other species of bats crowd larger caverns The combined body heat of hundreds of thousands of them raises the temperature to over 110 degrees The urine-soaked floor ensures the chamber is very humid perfect for bats, and purgatory for anyone other than a dedicated bat scientist Cuba is home to millions of bats and with so many bats, it's no surprise that there is a predator the cave boa These snakes have a special technique for catching their prey In a pitch dark, the draft of a wing beat stimulates them to strike The caves that are home to the snakes and bats were formed by underground rivers Over millions of years, as the level of land and sea fluctuated, these rivers found new courses New caves were created and old ones drowned The result is that water-filled caverns are scattered throughout the limestone landscape of the dry forest Some connect with the sea and have salt water Here, surrounded by forest, reef fish can feed on fruit These caverns reveal their past to divers Their chambers are decorated with stalactites and stalagmites that could only have formed when the cave was full of air The water is crystal clear, filtered by its journey through the limestone and light can penetrate deep into the cavern The beyond the limits of daylight is a world into which only specialized cave divers may venture The divers always explore as a team, for this is dangerous work The caves are a labyrinth of passages and chambers This Cuban cave diving group has been exploring and mapping this dark world for many years These inner recesses of the Cuban underworld hold their own secrets the remains of a human that fell in long ago But there is life here, too, over 500 yards from the surface, beyond the narrowest of passageways The life this deep in the cave has evolved to live in perpetual darkness The light of a diver's torch may be the first this fish has ever experienced and it doesn't like it The fish's scientific name is Lucifuga the animal that flees from light and that's most appropriate Little is known about this unique Cuban cave dwellers, for they are rarely visited and shun light It's thought they evolved from fish that lived in the depths of the sea That dark world may well have prepared their ancestors for life in these caverns Here, they slowly lost their eyesight and the pigment in their skin becoming mysterious ghostlike creatures It should surprise no one that fish arrived on Cuba by swimming But 12 million years ago, a less obvious candidate arrived by the same means The ancestors of this lizard, the rock iguana crossed the sea from Central or South America, a distance of 125 miles or more Though they look incongruous, the iguanas are actually good swimmers and when they tire, they can inflate their chests and float like corks whiles they take a break By a combination of hitching lifts on floating vegetation, drifting and swimming a few iguanas found their way to the shores of Cuba Those that did, became the founders of a dynasty No competitors and lots of space Cuba must have seemed a paradise a paradise that is apart from the flies The large flies accompany the iguanas and drink the fluid in their eyes Like most creatures that arrived on islands, but unlike the bee hummingbird and the butterfly bat, the iguanas grew large An adult male can be 5 feet long and weigh as much as 20 pounds They carved out territories on their new island home males signaling their ownership with vigorous head bobs If an intruder ignored the message, direct action was called for Despite their fierce appearance and impressive size rock iguanas are for the most part peaceful vegetarians The iguanas arrived on Cuba before the crocodiles and many of the birds, bats and fish But another kind of lizard had colonized Cuba long before the iguanas They were carried to these shores on rafts of floating vegetation as long ago as 30 millions years At that time, the sea level was changing rapidly tuning mountain ranges into islands And isolated on each island new species of these small Anolis lizards evolved Today, there are around 55 different species of these fiercely territorial creatures Some species are adapted to life on the rocky forest floor others live on sedges and grasses Many dispute for space on the bushes and low trees They all have a dewlap, but have evolved different ways of showing it off There are even anoles in the tops of the tallest plants like this blue anole The story of the anoles is a clear example of an ancestral animal evolving into many different species to fill all the different habitats Despite their variations, the vast majority of anoles have the same lifestyle They are fast-moving insect hunters But, there are exceptions This treetop anole is a slow-moving snail eater You don't need to move quickly when you eat snails but as a consequence, this anole is plagued by mosquitoes The anoles have had 30 million years to evolve into a huge array of species each carving a niche for itself on Cuba But there were animals on Cuba before the anoles arrived One possible ancient Cuban can be found in the woods that clothe these steep limestone mountains The Cuban tody is diminutive There are only 5 species of tody in the world, all found on Caribbean islands and the Cuban tody is the most colorful of them all Todies defend a tiny patch of forest They are real stay at homes, rarely leaving their territory and never leaving the shelter of the forest They feed by snatching insects off leaves flying no more than a few yards on short rounded wings Is it conceivable that this tiny bundle of feathers could have flown 125 miles across the sea to Cuba? Well, the tody may not have moved to Cuba Cuba may have traveled to the tody Millions of years ago, before Panama existed Cuba was much closer to the continent At that time, the tody could easily have fluttered the short distance from America In Cuba's remote rainforests live other creatures that can claim to be ancient Cubans Their ancestors joining the island before the tody This is an Eleutherodactylus frog It is one of over 60 species Like the anolis lizards, they've carved up Cuba Some lived on the forest floor, others, along the streams There are even Eleutherodactylus frogs in the treetops, living amongst the air plants You could argue that the todies may have flown to Cuba and that these small frogs they may have survived a long sea journey aboard a raft But scientific evidence suggests that they were early pioneers that hopped aboard 70 million years ago They have one big advantage as pioneers Their tadpoles don't need freshwater In less than 20 days, the embryo transforms from a few cells to a miniature adult inside its transparent sphere This remarkable adaptation allowed the frogs to live far from water These small frogs emerged from their eggs to colonize Cuba from the treetops to the forest floor Luis Diaz is the Cuban authority on Eleutherodactylus frogs He and his colleagues have discovered several new species in the last few years The most remarkable of these was found as recently as 1996 They live in the leaf litter on the rainforest floor To find them, you have to kick up a bit of fuss The creature has a very Cuban distinction In a family of small frogs, it is the smallest In fact, it's the smallest four-legged creature in the world This is an adult It's a third of an inch long The frog fits comfortably on a thumbnail At this size, a female can only produce one egg These frogs may have reached the limits of miniaturization Cuba's journey didn't start 70 million years ago when the frogs joined It was on the move before then Going back in time, Cuba was not in the Caribbean, but the Pacific Could any animals have lived on Cuba as it moved through the Pacific Ocean? For part of that journey, Cuba itself may have been submerged So the seas are the most likely place to look for an animal whose ancestors may have prowled the rocky shoreline of Cuba around 80 million years ago The goliath grouper lives in rocky canyons and caves Today, it can be found in both the Caribbean and Pacific so its ancestor might have patrolled Cuban Pacific waters long ago It ventures out at night onto the sandy plains of the sea floor It has an Epicurean's taste for lobster but a glutton's appetite This goliath grouper weighs 440 pounds and so a 4-pound spiny lobster is just a bite-sized snack A grouper this large can consume many lobsters in a night All big groupers are females as the males change sex as they grow The mouth on a 6-foot-long female is over a foot and a half across Plenty of room for another lobster The ancestral goliath grouper may have lived in Cuban waters millions of years ago but could the ancestors of any Cuban land animals have lived there we can never be sure, but a bird might have Flamingos are strong flyers and have an ancient heritage There are fossils from over 50 million years ago Ancestral flamingos could have colonized the muddy shores of an ancient Cuba in the periods when it was above the sea Today, Cuba is home to the largest colony of Caribbean flamingos in the world over 100,000 birds Their nest close together in a remote part of the coast They seem to need the company of other flamingos but still bicker over space The rich thick mud is a great benefit to the flamingos It stops predators from approaching the colony and it provides the raw material for the nests but it also clogs the feathers of the nesting birds The nesting flamingos have a strict daily routine They sit during the heat of the day to protect the eggs from the tropical sun Then as the day cools, they gather into groups and fly to the nearest freshwater to drink and bathe This could be an image from the distant past a daily routine that may have taken place millions of years ago If there were land animals on Cuba over 80 million years ago they may well have been flamingos that we may never know for certain But no land animal could lay claim to the title of the oldest Cuban That must go to a creature that could have visited primordial Cuba when it was still being created by the forces of the earth over 600 miles out in the Pacific Cuba then would have been a raw new island with little vegetation But its remoteness and lack of land animals would have suited this possible first wild Cuban for it would have required only a sandy beach Cuba was born 100 million years ago but there would have been turtles then as there are today For these marine reptiles have a most ancient lineage Female turtles only come ashore to lay their eggs Dry land is not their world and they are clumsy and uncomfortable here The whole visit takes little more than an hour and then the turtle returns to its world the sea But a brief visit just like this may have been the very first life on Cuba The story of wild Cuba runs for 100 million years In that time, as the island moved from the Pacific to the Caribbean many creatures have arrived on its shores Today, their descendants live alongside more familiar Cuban icons But it is these unique creatures that make Cuba the "Wild Island of the Caribbean"