The snakes are on the alert. This is the best feeding opportunity they will get all year. On flat ground, a baby iguana can outrun a racer snake.
Another hatchling has its first glimpse of a dangerous world. A snake's eyes aren't very good, but they can detect movement. So, if the hatchling keeps its nerve, it may just avoid detection. Near miraculous escape The lucky survivors could begin learning the unique way of life demanded by this hostile island Christmas Island in the Indian Ocean.
For millions of years this remote speck of land has been ruled by crabs. Their ancestors came from the sea, but most have now adopted a land-based existence. Given there are so many of them, they get along relatively harmoniously. They're the gardeners and caretakers of a tiny crab utopia. Once a year, they must all return to the sea to breed, and the March of the Red Crab There are 50 million of them.
It's an event that has brought the island worldwide fame. But in recent years, millions of red crabs haven't managed to reach the sea. An invader has occupied this island.
Yellow crazy ants. They escape from visiting ships, and with no predators to control them, they have now created vast super colonies in the forest. When migrating red crabs march into their territory, the ants attack, squirting acid into the crabs'eyes and mouths. The crabs have no defense.
Blinded and confused, they're doomed. Humans brought these ant invaders here, and now humans are having to control them. Isolated communities may evolve for millions of years in relative peace.
But when new challenges arrive, they can struggle to cope. Of all the species that have become extinct in recent years, around 80% have been islanders. Losing its fear of humans has enabled one animal to spread into cities everywhere and in huge numbers.
Pigeons are by far the most successful urban bird. Here in Albi in the south of France, the pigeons come to the river to bathe. They need to preen their flight feathers, clean off the city dust and cool themselves down.
Death lies in wait. A predator that has taken advantage of the very thing that has led to the pigeons'success. Their lack of fear.
As the pigeons bathe, oil from their plumage flows downstream and is detected. Monstrous Wells catfish. Introduced here just 40 years ago, they have proliferated. Virtually exterminated the local fish stocks and they've now developed a taste for pigeon.
Their eyesight is poor, so they use their barbels to sense the movements of their victims. This is a radical new hunting strategy for what is normally a bottom dwelling fish. After a thousand years of living in this city, pigeons are now having to learn to avoid a fish.
Danger past. And that's just as well. Because he is a father. And he's guarding some very precious eggs.
For the last few weeks, females, one after the other, have visited him and entrusted him with their offspring. Some are now almost ready to hatch. There are several clutches on the reef, and those at the top, the most recently laid, are barely a day old. But in the jungle, there's always someone out to get you.
This wasp is a specialist hunter of frogs'eggs. It's noticed the wriggling tadpoles at the bottom of the leaf. He mustn't move.
The youngest eggs are the most vulnerable, and he can't guard them all. But these tadpoles are not as helpless as they might appear. Incredibly, the unhatched tadpoles can sense danger and the oldest and strongest wriggle free and drop into the stream below.
The eggs at the top of the leaf, however, are still too young to hatch. And now the wasps know they're there. But the male's back looks very like the youngest cluster of eggs.
And that seems to confuse the wasps. Using his own body as a decoy is a huge risk. The wasp's stings could kill him. He's managed to save most of his young. He'll have to remain on guard for another two weeks.
But in the jungle, just surviving the day can count as a success. A thousand plants growing on one single tree. Throughout the forest, this story is repeated endless times. As a consequence, jungles are home to more species of plants than anywhere else on Earth.
And they, in turn, support a wealth of animals. In Ecuador, the competition is at its most intense. Here, there are a hundred species of hummingbirds alone. All fighting for nectar. Each flower only has a small amount at any one time, and so it's first come, first served.
One hummingbird has gone to great lengths to avoid conflict with other species. Swordbills are the only bird with a beak longer than their body. And some flowers are too elongated for the other 99 species of hummingbirds here to feed from them. A sword builds extraordinary beak harbour, enables it to reach the places that others can't.
The top of this flower, where the sweet nectar is produced. It has found a solution that means it doesn't have to join the fight. And as each long flower blooms, it gives the sword bill a fresh supply of food all to itself.
But having a beak longer than your body does have its drawbacks. For a start, it's tricky to keep it clean. Harder still, how do you preen your body feathers? Unlike the other Hummers, sword bills can't reach their feathers with their beak.
The only option... a good old scratch. It's a little unrefined, but a small price to pay for an exclusive food supply.
And many animals here choose the simplest option of all. Staying hidden all day and only venturing out in the cool of the night. As darkness falls, animals appear from seemingly nowhere.
And among them, inevitably, are hunters. One of the most voracious nocturnal predators is also one of the hardest to see. This mysterious creature hardly ever appears on the surface of the dunes. But there are signs on the sand that can give it away. It lives only here where the sand grains are so perfectly dry and polished that they flow almost like water.
It's no bigger than a ping-pong ball, a golden mole. It's totally blind. But there's nothing to see underground anyway. Instead, it has superb hearing. Its entire head acts as an amplifier that picks up vibrations through the sand.
So, to locate prey on the surface of the dune, it has, paradoxically, to thrust its face into the dune. Termites. Not easy to catch when you're blind.
Far better to go into stealth mode. Once below the sand it can detect the slightest movement. Allowing it to strike with pinpoint accuracy. Well, most of the time. It can travel a kilometre a night in search of its dinner.
And right now, it has just detected its main course. Little wonder it's sometimes called the Shark of the Dunes. It's July in the deserts of Nevada in the Western United States.
The hottest time of the year. Bands of wild horses, mustang, are converging on one of the last remaining water holes around. Now, water not only offers them the chance to drink, it can also bring power. If a stallion can control access to water, he will have secured mating rights to the entire herd.
So stallions try to dominate these pools, fighting off rivals who venture too close. A stranger. He's traveled 15 kilometers to be here because the pools where he's come from have already dried up. With him come his females. If he can't provide them with water, they will leave him for the White Stallion, who already dominates this pool.
So, he will have to fight. There is everything to lose. A broken leg or a shattered jaw would mean a slow and painful death. No! Mist kick and it's all over.
The new arrival has won. And his prize is more than just a chance to drink. He has provided for his herd and in the process, stolen his rival females. The White Stallion's rule is over.
Meadows that only a few weeks ago were buried beneath the snow are now full of life. But in these mountains, the good times will not last long. So the bears must feed as fast as they can. During the summer months, an adult can put on 180 kilos, gorging on plants.
And if they can catch them... a marmot or two. But just now the bears have something else on their minds. It's becoming warmer and the bears are keen to shed their thick winter coats.
Mothers show the cubs what to do about this. They'll soon catch on. Some trees, it seems, are particularly suitable for rubbing. Bears have their favourites and will travel long distances to visit them.
Some itches just have to be scratched. 30 bears in this one valley. As they rub, each leaves an individual and recognizable scent.
So the tree soon carries a list of who's around, which might help individuals to avoid a fight. To best spread their scent, they really have to put their back into it. But summer is short.
Itches satisfactorily scratched. It's time to eat. In a couple of months, they will have to return to their dens to hibernate. So now they must put on as much weight as they can. They're setting off on the greatest overland trek made by any animal.
But wherever grass eaters travel, predators lie in wait. Here they are, Arctic wolves. They must seize their chance while the caribou pass through their territory.
The wolf runs at the herd, trying to flash out the weak or the slow. A calf is separated. At full tilt, 60 kilometers an hour, the wolf is just faster.
But the calf has stamina. Only a few weeks old, and this calf's will to survive is remarkable. And it needs to be. For these young caribou have now started a journey that will last a lifetime. Forever chasing the seasonal growth of the grass on which they depend.
Like all grassland creatures, they are at the mercy of these unpredictable, but ultimately bountiful lands. Grass can survive some of the harshest conditions on Earth. Flood, fire and frost, and still flourish.
So it is, the grasslands provide a stage for the greatest gatherings of wildlife on planet Earth. 60 million tonnes of snow now blanket this herd's territory. Pushing through deep snow is exhausting work, and the bison are now slowly starving.
Just keeping warm saps huge amounts of energy. Their thick coats can insulate them down to minus 30 Celsius. It's now minus 40. The only thing that will keep them alive is buried beneath a meter of snow.
And that's a problem shared with a surprising neighbor. The Foul de Fonk 6 is also deep beneath the snow. The survival of both creatures depends on getting through to the ground.
For the bison, it will be a matter of brute strength. Massive neck muscles enable them to shovel five tonnes of snow a day. Their lightweight neighbour needs more precision.
The bison have reached their goal. A mouthful of withered grass. And where the bison have dug, the fox now spots an opportunity.
Every footstep counts, but he mustn't break through... yet. He listens carefully to pinpoint his target.
It's moving. A vole. Small, but a hundred times more nutritious than a mouthful of dried grass. To get through the winter on these prairies, sometimes brain beats brawn.
And this bobcat may be in luck. For this particular valley is blessed. A river here never freezes. It's fed by a volcanic hot spring that heats these waters to 50 degrees warmer than the surrounding air. Hungry animals of all kinds come here to feed.
Throughout the winter, the river is full of food. for those who know how to catch it. Here, even the coyotes have become fishermen. But hunting is hard for a cat that's not used to getting its feet wet. So he must choose his target with care.
Golden-eye ducks. But can he get close enough to pounce? Perhaps you'll have more luck on the other side.
Here, steam from the river warms the surrounding trees. So up in the branches, there could be prey. If only he could get to it.
It's six metres up. At last, a squirrel. Not much, but enough to keep him going.
To survive a winter in these mountains takes tenacity. And bobcats have that in abundance.