"NARRATOR:" "Far out in the eastern Pacific, is a scattering of islands ruled by the brutal forces of nature." "A land ravaged by fire." "At the mercy of an ocean that can nourish, but also cripple." "A world in turmoil." "This is the story of how life in Galápagos is shaped by the relentless forces of change." "Past, present and future." "Galápagos lies 600 miles off the coast of South America, right on the equator." "It's one of the most volcanically active groups of islands in the world." "And on its western edge, towers the most imposing, most hostile of them all." "A colossus called Fernandina." "In the last 200 years, this volcano has erupted at least 24 times." "Its caldera towers a mile above sea level, but there's one animal that has no option but to scale its summit." "The land iguana." "Every pregnant female needs to find a patch of volcanic ash in which to lay her eggs." "But suitable sites are few and far between, and the best, warmed by fumaroles, lie right on the rim of this giant." "Climbing there is a punishing ordeal, which can take weeks." "This female has not timed her journey well." "All the good sites have been taken, so she has no choice but to challenge those in residence." "Aggressive body language can sometimes force a victory." "But the rightful owner won't relinquish her ground easily." "So it's all or nothing." "(HISSING)" "A ruthless catfight." "The pregnant female is sent packing." "Evicted from the prime nesting grounds by her rival, she is now forced to look elsewhere." "But the only other suitable sites on Fernandina lie deep within this giant caldera, half a mile down." "She must make a terrifying descent." "The smallest slip could be fatal." "Countless iguanas have been buried by landslides." "But this female has a lucky escape." "For any animal, finding a foothold on Galápagos is tough work." "This cluster of islands are the product of a volcanic hotspot, where scorching rock rises from hundreds, possibly thousands of miles beneath, to puncture the Earth's crust." "There are six highly active volcanoes in Galápagos today." "One erupts every few years, sometimes for months at a time." "Volcanism is the fundamental force in Galápagos." "It can build an island in just tens of thousands of years." "And it can wipe out life in an instant." "After such catastrophic events, animals and plants are forced to find new ground." "The fresh, sinewy lava fields seem as lifeless as Mars." "But the Lava Cactus is a tough pioneer." "It's one of the first plants to invade this baking hot terrain, storing moisture in its succulent stems." "And where the lava reaches the coastline, mangroves anchor themselves to the rocks." "Four species have managed to colonise the brittle shores of Galápagos, their salt-tolerant seeds brought here on the ocean currents." "Settling in bays and inlets, the roots accumulate all sorts of silty debris, helping to offer life a purchase on the shoreline." "Mangrove forests are crucial nursery grounds for fish, fed by plankton and nutrients flowing in and out with the tides." "The tangle of vegetation also provides welcome shade from the equatorial sun." "(BIRDS CHIRPING)" "But even mangroves struggle to settle on the newest and most exposed lava shorelines." "There is, however, one animal that has learned how to benefit from this harsh volcanic terrain." "The Galápagos fur seal." "Its ancestors arrived here long ago from the subantarctic." "To escape the midday heat, they've discovered cold hideouts." "Lava grottos, formed by networks of broken lava tubes." "The labyrinth of caves and tunnels provide perfect shelter for fur seals, the smallest of their kind in the world." "They are a third the size of their sea lion cousins which also visit these grottos." "Fur seals have naturally thick pelts which provide good insulation, helped by air trapped among the fur." "Big, bulging eyes allow them to hunt in the dark, a strategy that avoids direct competition with sea lions." "Though fur seals normally court on land, adolescents will sometimes test the water with one another beneath the waves." "Geological force in Galápagos has created a cluster of islands, of all shapes and sizes." "Some are pillars of compacted ash." "Others, forged from explosions of lava." "More than a hundred islands, islets and rocky outcrops sprinkle the ocean." "The most unusual lies in the far north-western reaches of the archipelago." "Roca Redonda." "This giant slab of unscaleable rock stands 1 ,000 feet tall, and is a precious outpost for nesting seabirds." "(BIRDS CHIRPING)" "Swallow-tailed gulls are among the rarest and most exquisite." "(SCREECHING)" "They are the only nocturnal gulls in the world and they forage at night for small fish and squid in the surface waters, aided by their unusually large eyes." "This island teems with life" "and the productive seas that envelop it hide the secret to its wealth." "There's far more to Roca Redonda than meets than eye." "This island is actually the tip of a giant undersea volcano, nearly two miles tall and 1 2 miles wide." "Bathymetric studies, examining the depths of the ocean using sonar tracks, give the archipelago a whole new dimension." "Galápagos is a chain of submarine volcanoes that have coalesced into a vast underwater platform." "This monumental plinth drastically changes the routing of the currents that sweep its flanks." "It forces the cool Cromwell Current, heading in from the west, to surge up from the ocean floor." "As night falls, this mineral-rich upwelling brings the supernatural to Galápagos." "The most bizarre creatures rise from the abyss." "A vertical migration in a three-dimensional world." "Some of these ocean vagrants are floating fortresses, providing precious shelter." "For others, like this mantis shrimp larva, being small and inconspicuous is key to survival." "Young slipper lobsters are exquisite glass sculptures," "while cone jellies are far more flamboyant, beacons of colour in a sea of darkness." "Galápagos as it's never been seen before." "As day breaks, the nutrient-rich Cromwell Current is bathed by the equatorial sun, triggering blooms of microscopic algae, that feed an explosion of life." "This vital current has helped some of the strangest Galápagos creatures, like these cold-water penguins, to live at this latitude." "The Cromwell Current is only one of many that feeds Galápagos." "Flowing in from the south comes another cold current, the H umboldt, merging with the South Equatorial Current, heading west." "And from Central America comes the warm Panama flow." "This current is poorer in nutrient than the others, making these northern waters the least productive." "Animals here need to be resourceful." "Shoals of bigeye jacks gather at particular cleaning stations, attracting the attention of colourful barber fish." "The barber fish like to feed on skin parasites from the jacks." "It's a mutually beneficial arrangement." "Despite being on the equator," "Galápagos has a limited number of warm, stable pockets of water." "There are just a couple of dozen species of coral." "Pavona corals bear the scars of an assault by Guineafowl Pufferfish." "They pluck crunchy mouthfuls of algae." "Coral erosion helps to create an important feeding ground for spotted eagle rays." "They prefer corners of Galápagos where the remains of corals and shells mingle with eroded lava." "They' re rich in molluscs and crustaceans, which the rays root out with their powerful, crushing jaws." "These aquatic prairies are also home to rather nervous local residents." "They seem to find the rays particularly intimidating, although there's no real threat." "Galápagos garden eels, who intercept plankton passing by." "In the rest of Galápagos, cold and fertile waters prevail, nourishing fields of green algae, richer here than anywhere else on the equator." "This is an important food for gangs of Yellow-tailed surgeonfish." "This algal farmer, a solitary damselfish, suddenly finds his harvest hijacked by marauders." "These marine pastures are a choice habitat for an ancient ocean wanderer." "The Pacific green turtle." "It's thought the Galápagos turtles are a unique subspecies, as they' re unusually dark, perhaps to help them absorb the sun's warmth and cope better in these chilly waters." "Here is one of the richest concentrations of green turtles anywhere in the Pacific." "Green turtles time their gathering carefully." "For few months a year, they come together to greet and mate." "Even in the most challenging conditions, nothing stops this ambitious male from completing the task in hand." "Most green turtles lay their eggs on these shores during the warmer season, when the H umboldt Current slackens." "Perhaps that warmth helps with incubation." "But their hatchlings will emerge several months later, at a time when this cold current re-establishes itself with gusto." "For half the year, the H umboldt Current dominates Galápagos." "Arriving with cool and dry south-easterly trade winds." "And it brings with it the garua season." "The misty season." "It's now, with upwelling at its strongest and the waters most productive, that turtles, fish and seabirds can bank on a steady supply of food." "(BIRDS SQUAWKING)" "Three-quarters of the world's population of Blue-footed Boobies live in Galápagos." "They react fast when conditions are favourable." "Feet are handy brakes." "The name "booby" derives from the word "bobo ", the Spanish for clown." "Perhaps because of their exaggerated footsteps." "This courtship dance is a Galápagos ritual." "The higher his foot-lift, the better his chances." "Sky pointing builds her interest." "(SQUAWKING)" "She commits, mirroring his every move." "It's back to basics." "Boobies can switch off their breeding season at any moment, if the ocean fails to deliver." "In a good year, two or three eggs are laid, with both parents taking turns to shade and incubate." "Nazca Boobies are close relatives of Blue-footed Boobies, but feed much further off-shore, with a wider hunting range." "They also have a fixed breeding cycle." "But there's a twist in their tale." "Nazca Boobies lay two eggs, and if both successfully hatch, there's an age gap of three to seven days." "The older, larger chick is quick to stamp his authority." "It's a brutal, bullying business." "The elder sibling pushes the other as far from the nest as possible." "Although this happens right under the mother's beak, she does nothing to intervene." "The evicted chick now faces certain death, through dehydration or predation." "Only one chick ever survives." "No one fully understands why siblicide always occurs among Nazca Boobies." "Do the parents produce two eggs as an insurance policy in case one is destroyed?" "Or is this an evolutionary relic from the past, when this species was comfortably able to raise two young?" "Whatever the case, for Nazca Boobies this system is very effective in a world where the stakes are so high." "In Galápagos, the ocean is both a giver and a taker." "Life has found some extraordinary ways to deal with its mood swings." "But on these remote shores, it's still a hostage to the elements." "(FLIES BUZZING)" "(GRU NTING)" "Every three to ten years, conditions in Galápagos get seriously out of kilter." "(TH U N DER RUMBLING)" "It's an event described by the people of Ecuador and Peru as El N iño, meaning "the boy child", because it often begins around Christmas." "Trade winds diminish, and the cool H umboldt Current slackens, failing to make its impact felt in Galápagos." "It is replaced by much warmer surface waters, moving east across the Pacific." "Tropical downpours sweep in, bringing welcome relief to the land." "(TH U N DER RUMBLING)" "Rivers are born." "Plants flourish." "But the impact of El N iño on the ocean is catastrophic." "When it last struck, most sea lion pups starved to death." "Mothers were unable to produce enough milk, because of extreme shortages of their main prey, sardines." "In some colonies, more than half of all sea lions died." "For marine iguanas, the impact of El N iño can be just as dire." "Warmer water wipes out green algae, their main food source." "These islands depend on the ocean as a provider of life, but nothing is guaranteed." "Profound geological and climatic forces constantly re-shape Galápagos." "Life here is resilient and adaptable to change, and with time, it can recover from natural catastrophe." "(BIRDS TWITTERING)" "Galápagos is the most pristine tropical archipelago in the world." "95% of native wildlife is still intact." "Isolation has helped protect these islands." "But in recent times, a new force of change has emerged, one that is rapidly gaining momentum." "Ourselves." "More than 1 00,000 visitors come to Galápagos each year." "To help support this growing interest, the local population has dramatically risen in the last 50 years, from less than 2,000 to 30,000 ." "The resources needed to sustain visitors and residents are spiralling." "There's a now a sort of air and sea bridge with mainland South America." "With a constant stream of people and goods, Galápagos is no longer isolated." "And with this flow of traffic, come unwanted species that threaten the delicate status quo." "Already there are more introduced plants here than native ones." "Quinine trees, brought in as a medical crop, swamp natural habitat where rare birds like petrels nest." "(DOG BARKING)" "Despite efforts to curb the problems, the challenges keep on growing." "(GOAT BLEATING)" "Of all the introduced species, goats have been the most destructive." "They were brought here centuries ago by buccaneers, whalers and sealers as a reliable food supply." "But they've stripped the native plants, out-competing animals like giant tortoises." "Hard though it is, the only viable solution to this problem is eradication." "(FIRING)" "Over the last two years, tens of thousands of goats have been removed from two of the largest Galápagos islands." "The land now has a chance to recover." "Galápagos was, for centuries, feared and reviled." "But ever since Charles Darwin's visit nearly 200 years ago, we've seen these islands in a new light and it has captured the attention of the world." "This archipelago is a fascinating crucible for life." "It continues to evolve and surprise." "So great was its impact on Darwin, that he would later claim the Galápagos Islands to be the origins of all his views." "Today, it is our impact on Galápagos and how we choose to manage it, that will determine the islands' future." "If that succeeds, it can point the way for everyone." "Galápagos is, after all, a microcosm of our planet."