"Vast open plains." "Immense spaces." "Eerie silence." "But any feeling of emptiness is an illusion." "The plains of our planet support the greatest gatherings of wildlife on Earth." "At the heart of all that happens here is a single living thing." "Grass." "This miraculous plant covers a quarter of all the lands of the Earth." "but not enough to sustain a forest." "Some are huge." "The Central Asian Steppe alone extends one third of the way around our planet. scanning the ground beneath for signs of prey. one of the planet's great migrations is underway." "Few people ever see this extraordinary annual event." "Mongolian gazelle." "but no one really knows. but once a year they come together to have their young." "Nearly all will give birth within the next 10 days." "communal calving is the safest way to have young. it's almost impossible for predators to sneak up." "no trees." "There's only one thing to hide behind." "Grass." "And it's not very effective." "Predators also have a hard time raising their young on open grassland." "eagles have to nest directly on the ground." "All the inhabitants of the Great Plains are exposed to the elements." "Fire sparks panic in the herd." "Gazelles are born to run if they can avoid being trampled. the blaze consumes anything that can't flee." "have been lost." "the old and the weak." "The gazelles move on to new pastures and leave the desolation behind them." "From the ashes rises the phoenix." "the incredible survivor. grass is almost indestructible. it covers more of the Earth's land than any other plant and feeds more wildlife than any other." "Red-billed quelea." "0ne and a half billion swarm across the savannahs of Africa." "These are the most numerous birds on Earth." "Some flocks are so vast that they can take five hours to pass overhead." "0nly grass can feed plagues of these proportions." "The ravenous hordes devour the seeds." "And the leaves and stems are cropped by great herds of antelope." "The East African savannahs alone sustain nearly two million wildebeest. but within days the plant will recover and continue to sustain the biggest herds on Earth." "Grass is not confined to the tropics." "It manages to grow even in the bitter conditions of the Arctic." "the planet is barren and ice-locked." "A frozen no-man's land at the end of the Earth." "dark winter releases its grip." "Temperatures rise and grass that has lain dormant and frozen throughout the winter sprouts once more." "Green returns to the Arctic." "The receding ice reveals an immense flat plain the size of Australia." "This is the Arctic tundra." "silent wilderness." "But it's about to change." "Snow geese. and in spring they fly the entire length of North America to reach the Arctic tundra." "Five million birds make this journey every year." "000 miles long and has taken them three months. back at their traditional breeding grounds at last." "Snow geese pair for life." "they must stake a claim to a nesting patch." "Ideal sites are in short supply and quarrelsome neighbours are all around." "Disputes can be vicious." "Point taken!" "the tundra is the ideal place for a grazer." "intense summer and there are fewer predators than further south." "geese can nest on the ground in relative safety." "this female must incubate her eggs for three weeks and throughout this time she will be very vulnerable." "An Arctic fox surveys the colony." "She's been waiting for the geese all winter." "Sneaking up unnoticed is impossible." "Perhaps fortune will favour the bold." "The colony is well-defended." "There are no easy pickings here." "but hunger compels her to continue." "There are more eggs here than she can possibly eat now." "But the nesting season is short." "So she stashes much of her plunder for later in the year when all the geese have gone." "other bigger predators prowl the tundra." "Wolves." "finding food on the plains is an even greater challenge." "it's also hard to find." "They've been searching for days without a sign." "Somewhere in this immense landscape there is food for them." "This is it." "Caribou. 000 miles during the summer months." "The wolves will starve if they don't find the caribou." "But it's no easy task to locate prey that never stops travelling." "Biting flies and the quest for new pasture drives the migration ever onwards." "A wolf has finally picked up the trail." "The caribou are close." "a chance." "The hunt is on." "and the weak and young are singled out." "A calf is separated from its mother." "it's high summer and eggs are hatching." "a marvel of timing." "The colony is now home to a million goslings." "The fox is still gathering all she can get." "Sometimes one mouth simply isn't enough." "0ne will have to do." "Not all food is stored." "Some is needed right now." "She has seven hungry cubs to feed." "the mother must work tirelessly to raise her family." "healthy cubs will survive the Arctic winter." "The vast majority of the goslings are still flourishing." "Their parents lead them down to the safety of the water as soon as they're strong enough to make the journey." "boom time has come to an end." "But the mother has given her cubs the best possible start in life." "The geese will continue grazing the tundra until the summer ends and they're forced to head south for the winter." "the sun's rays are weak and grass can only grow here for a few months a year." "summers are longer and the grasslands flourish." "The prairies of North America." "This rich pasture once supported the greatest herds ever seen on our planet. but no animal is immune to intensive hunting by man or the destruction of its habitat." "000." "the species is recovering. and the grass here can support herds all year round." "Male bison weigh in at one ton." "the bulls are fat from the rich grazing but only a few will mate." "Exactly which few is about to be decided." "summer is a time for growth and reproduction." "Now the grass produces its flowers." "New colours also come to the plains. and nowhere is more impressive than on the veldt of South Africa." "Not all temperate plains are so rich and colourful in the summer. the highest great plain in the world." "grass survives those of the wild yak." "life is hard." "Temperatures rarely rise above freezing and the air is thin. the Himalayas. and this casts a giant rain shadow that leaves Tibet high and dry." "Grass clings to life even as desiccating winds remove what little moisture remains in the soil." "so can grazers." "Wild ass." "The males are fighting to win territories." "Those that hold the best are more likely to attract a herd of females." "It's a frisky business. but he can't assume the females will actually turn up." "Female asses are mysterious creatures." "They come and go as they please and much of their behaviour seems unfathomable to an outsider." "They're the great nomads of the plateau and will often trek vast distances across these parched plains in search of oases. they are liable to feed and drink for just a few hours and then head back to the dust for no apparent reason. but the most numerous grazer in Tibet lives underground." "feeds on grass." "pikas never stray far from their burrows." "squatters will move in given half a chance. they're worth tolerating because they provide a valuable early warning system." "The bizarre Tibetan fox." "The pika's nemesis. perhaps helped by its curious body shape." "But why the square head? wet air from the south." "But the water never arrives." "it's forced upwards by the Himalayas and condenses into huge rain clouds." "These clouds drop all their water on the southern side of the mountains." "The very peaks that keep Tibet dry are responsible for the monsoon rains falling farther south and the greening of India. grass reaches its full potential." "Elephant grass is the tallest in the world." "Grass that towers over an elephant can conceal all sorts of surprises." "The male Lesser Florican." "It's hard work getting noticed when you go courting in high grass." "The long-grass plains of tropical India are home to some of the largest grass-eating mammals on our planet." "And some of the smallest." "Pygmy hogs are no bigger than rabbits." "They're the tiniest and rarest of all wild pigs." "but not for eating." "She's building a nest. but she does have 10." "given unlimited sunshine and water. the wet season is followed by a dry one. grazers are marching in search of grass and water." "these plains can become dust bowls." "Grass can now lose its hold." "Elephants are in immediate danger." "They must drink almost daily. they march hundreds of miles across the parched plains." "the matriarchs lead their families to those special water holes that saved them in previous years." "but they must share what remains with desperately thirsty animals of all kinds." "These are tense times. but as night falls the balance of power will shift." "Thirsty herds continue to arrive throughout the night." "It's a cooler time to travel." "the tables turn." "The elephant's night vision is little better than our own." "But lions have much more sensitive eyes." "The cats are hungry and the elephants seem to sense it. but desperate times require desperate measures." "easier targets." "But how to reach them?" "The adults encircle their young." "It's an impenetrable wall of grey." "A few exhausted stragglers are still arriving." "0ne of them is alone." "But it's too big for the lions to tackle." "This one looks a little smaller. but the whole pride is here." "There are 30 of them and they are specialist elephant hunters." "This elephant will feed the whole pride for at least a week. but they have no choice." "The dramas that play out here are a savage reminder of how important water is for all life on these plains." "Africa's baked savannahs undergo a radical change." "Rain sweeps across the continent rises again." "And the herds return. clinging to existence around tiny water holes." "the good times are back." "A few African savannahs are very special." "rainwater from far and wide flows across the flat plains." "but still it grows." "grass can withstand it all. grass replaces dust over great areas." "Fresh new shoots draw animals from great distances." "Many undertake epic migrations to catch the boom time." "Some resourceful animals live here all the year round." "but they have to change their behaviour if they are to gather what they need on the newly flooded plains. but getting to it can be a little uncomfortable. but they know where to find a dry seat." "Ajuicy snail is ample recompense for sodden paws. animals can now reap the rewards. the great plains are lands of feast and famine." "they support the greatest gatherings of wildlife found anywhere on Earth."