Strategy of Life | Part 2: The Battle for Survival | Free Documentary Nature

Earth is a beautiful, living and breathing planet where, including those we haven't discovered yet, millions of species co-exist. All lives belong to nature, and for each and every organism, every moment is a battle and a challenge. Survival is a sweet reward that can only be earned by endless effort. Being ruthless, nature demands great sacrifices to those wishing to leave offspring. They must fight to protect their territories and compete against each other to mate. They never cease to take on challenges for the sake of reproduction. To escape from the fear of extinction, they fight even more vigorously in the battle of reproduction. Extinction is the natural destiny of those who fail to adapt, and reproduction is what decides survival and extinction. Reproduction is the invisible battle towards the ultimate goal of life. Here is an introduction to that secret world. A rainforest in Indonesia. There is a small clearing in the middle of the thick forest. It belongs to a male Wilson's bird-of-paradise with gorgeous plumage. He looks very busy. For some reason, he is completely devoted to cleaning. This is a special stage where he can show himself off to a female, so he pays attention to everything, down to the last fallen leaf. After a long, busy cleaning session, it's finally time to invite a female. He shouts at the top of his voice, calling for a female. Only the male with a loud and clear voice and a neat stage gets to invite a female. But for some reason, no female is responding. This time, he calls even louder to reach the other side of the forest. A female Wilson's bird-of-paradise must be watching. But as the bird of the hour, she doesn't appear that easily. The male quietly reorganizes his stage. Without a female, he won't be able to display his beautiful plumage and dance moves. What could be the problem? Has the female met some other male already? The male is serious about dressing up his stage. If he loses the competition against other males, he will never get to mate. Finally, a female shows up. She inspects every inch of the stage, prepared by her potential mate. Will she like his work? The male anxiously waits for her verdict. He displays his green chest feathers, trying to impress the female. She shows just enough interest to make him anxious. Fearful that he won't get to mate, the male is unsure what to do. The female flies away. He lost. The winner takes it all, and the loser gets nothing. Mating competition of the male birds-of-paradise continues on top of trees. A red bird-of-paradise male is perched on the highest branch, calling for a female. Early morning, he spreads his colorful wings and tries to seduce a female. Beautiful wings and long, graceful tail feathers. Unlike the female birds-of-paradise, the males are colorful and gorgeous. Wanted to be chosen, the male shows off his beauty by flapping his wings and dancing. But his colorful feathers and exuberant mating dance not only attract females, but also predators. Yet, the male must accommodate the female's demands for his ultimate goal of passing down his genes. The male starts to dance his heart out. Mating is only allowed for those who win. The losers might disappear from this world without leaving any offspring. Finally, a female. The males flap their wings even harder to get noticed. The male with the largest and the most beautiful wings wins the female. Males must go to battle for the sake of reproduction, because that is the only way to leave offspring and merciless nature. Nature is the arena of endless competition for survival. Only those that adapt to the changing environment survive. The traits advantageous to survival get selected, while disadvantages get discarded. How are the peacock's beautiful tails advantageous to survival? The long peacock's tail is actually a burden for survival. But, the stunning male peacock's tail feathers are quite captivating for females. They are the most powerful weapon for mating. The more colorful the feathers, the more dangerous for survival. But, the males that overcome the setback and survive can prove the superiority of their genes. Females that prefer beautiful appearance, and males that acquired it to win the females. Competition for reproduction demands continuous transformation and adaptation in all life forms. In the dead of night, a life is born into the world. It is a damsel fly. Its birthplace becomes its habitat. The males guard their territories with their lives. The four wings that move independently. A damsel fly's flight is beautiful and elegant. The male and female damsel flies are different colors. The males have bluish green wings, and the females have plain, dark brown wings with a white dot. The male flies around, guarding his territory from intruders. He tries to seduce the female by flying. The female accepts the male. When the female gets into position, the male grabs her neck with his tail. The male has transferred the sperm near his chest. The female places her sex organ to the male's chest where the sperm is stored, and the mating takes place. This makes a pretty heart shape. It's time to lay the eggs. The female starts laying the eggs by attaching each and every one of them to the stems of an aquatic plant. While the female is busy laying eggs, the male goes into guard duty. He flies around the female, keeping the intruders out. On top of other males, he doesn't allow other females from laying eggs here. He stands guard until the female safely lays all the eggs. He fulfilled his duty to reproduce. After successfully leaving offspring, the male returns to nature. His offspring will continue to guard this little pond from now on. When autumn colors spread around the forest, aphids that feed on sap become especially busy. And it's for the purpose of mating. One of the reasons why farmers hate aphids is because they reproduce rapidly. Aphids have quickly adapted to environmental changes. They can produce both sexually and asexually. They reproduce sexually just before winter, and during this period, they are able to lay eggs. The aphid eggs look like yellow rice grains. The female lay eggs where the new shoots will develop in the coming spring. It is to make sure the newly hatched offspring can feed on fresh plant sap after the winter. Eggs are perfect for overwintering. It costs minimal energy to endure the cold weather. Spring has arrived. The eggs have turned black, and inside them are the baby aphids wiggling around. They are tough little critters that braved the freezing winter. The aphids have effectively adapted to the changing environment and survived. The aphids are changing again. In the spring, they reproduce asexually. They give birth to offspring without mating with males. And all the offspring are females. A female gives birth to one baby every 20 minutes. It's pretty impressive. Aphids won the competition against the environment, and they succeeded in mass reproduction. But, merciless nature's mysterious law prevents unlimited reproduction through natural enemies. The ladybug is enjoying a feast. He's protecting the plant from aphids. Nature finds balance through food webs. That is why organisms continue to battle to find the best means of reproduction and survival. Plants display their beauty with flowers of various colors and shapes. Flowers are the plants' reproductive organs. But because plants can't move, they can't pollinate themselves. Plants get help from insects, the messengers of love. Insects are busy delivering pollen here and there. Plants provide honey to insects, and insects help plants with reproduction. Plants also use the environment. One way is the wind. Some change the shape of the flower for reproduction. This Korean lady's slipper orchid is shaped like a pot. The entrance is small, so once a bee goes inside, it can't turn around and leave the same way. Instead, it is lured to the opening in the top where the pollen is. There are also flowers that are masters of disguise. The flower looks exactly like a female wasp, and it gives off a strong pheromone-like scent. A male wasp falls for the disguise and tries to mate, covering himself in pollen. The orchid successfully reaches its goal, which is reproduction. A fly lands on a flower. But suddenly, the petal moves and locks the fly inside. It's a trap. Trying to escape, the fly pollinates the flower. Plants have learned how to adapt to their environment over a long period of time. They've become expert strategists because they had to fight hard to survive. And during that process, they learned the art of seduction. The bird that feeds on honey gets necessary nutrients from flowers. To drink honey more effectively, they develop long beaks and tongues, and they develop special wings to hover like insects. This is an elaborate strategy. The plants devise to reproduce through a kind of seduction called honey. Organisms seeking honey became slaves for the plants' reproduction. Unable to move, plants had to become smarter to survive. Plants have been evolving for a very long time, and their battle for reproduction isn't over yet. A peaceful pond. The surface looks peaceful and quiet, but under the water, there is a silent battle going on. This is a giant waterbuck, the biggest aquatic insect of all. For some reason, he's busy climbing up and down the stem of a plant. He keeps climbing with his large forelegs that look like a muscular athlete's arms. And it's because of those things attached to the stem. These little things shaped like tiny melons are the giant waterbuck's eggs. To a giant waterbuck, protecting his eggs is the most important task of all. A male giant waterbuck is causing ripples on the water's surface with his abdomen. This is his mating dance. An interested female appeared. The male's efforts paid off, and they begin mating. When the mating is over, the giant waterbucks get ready to lay eggs. The male leaves in a hurry. Where is he going? He needs to find the safest place to lay eggs in this vast pond. The male came back to the female. This time, he urges the female. The female moves to the place the male has picked for her to lay the eggs. She is followed by the male. It is the male that takes the lead in breeding. The male climbs onto the back of the female and urges her to lay the eggs by pulling her body. The male stays with the female, helping her lay eggs like a midwife. With the male cheering her on, the female starts to lay the eggs. She releases foamy mucus. It acts as the glue that helps the eggs stick to the stem. Sometimes this foam acts as a shield, protecting the eggs from wind and natural enemies. A female giant waterbuck lays 70 to 80 eggs, but only 30% of them hatch successfully. So the giant waterbucks do their best to produce as many eggs as they can. The male caresses the female's back gently, showing his support as she uses every ounce of energy in her body. As if showing her appreciation for the support, the female does her best until the very end. What is happening? The male drives the female away now that she is done laying eggs. This is because a female giant waterbuck will eat even the eggs she just laid if she gets hungry. It is the male's job to take care of the eggs. The male climbed down the stem and wet himself before climbing back up. He provides moisture to the eggs because if they dry up, they won't be able to hatch. In order to have complete control over nurturing, the male never rests. Anything that gets in the way of his reproduction, even if it is his mate, becomes his competition. This is a cousin of the giant waterbuck, a small and flat apacus. They also have a unique method of reproduction. A male taps on the surface of the water trying to attract a female. The male mates with the female that answered his call. He makes love with the female several times. The female lays the eggs on the male's back, not on any leaf or rock. They chose the most ideal place to protect the eggs from natural enemies. Proteins stick together, acting like glue to keep the eggs from falling off the male's back. The male urges the female to lay more eggs on his back. If she doesn't lay enough eggs, he will accept eggs from other females. The male has to swim up to the surface frequently to get enough oxygen for the eggs. It's hard work. The females take advantage of this fatherly love. The goal is the same, but they have different ways of accomplishing it. Thanks to the male's sacrifice, the babies grow safely. When the babies hatch, they stick the breathing tube on their tail out of the water and breathe. From now on, they must survive on their own without help from anyone else. The male shakes his body to help the babies hatch. The male babies will grow up and repeat what their father did for them for their own offspring. Every fall when the river water gets cold, special guests visit Namdaecheon in Yangyang, Gangwon province in Korea. They are salmon. They spend most of their lives out on the sea, and when it's time to spawn, they come back to where they were born. Salmons travel long and far guided by the smell of the stream where they were born. After they spawn, the salmons die. But their death is never an end, because they have their offspring to continue their lives. The fried that are hatched after a painful process spend the first six months of their lives here, in the river where they were born. The fried, the fruit of the parents' salmon's sacrifice, now get ready for the sea fraught with danger. The path to reproduction is never easy or predictable. It is a joy reserved for those who overcome the dangers along that path. This is Russia's Kamchatka Peninsula, home to various species. Every July, salmons come to Kuril Lake in the Kamchatka Peninsula to spawn. Sockeye salmons turn the water red. About 20% of the salmons living in the Pacific Ocean spawn in the Kamchatka Peninsula. The salmons turn from silver to bright red during the mating season. The salmons must swim against strong currents to reach the spawning ground. The adversity they must overcome after a long and tedious swim is certainly bitter. It's midsummer, but the water is freezing, having come from melted ice. It is a painful journey. But no matter how harsh the environment, it can't discourage the salmon's desire to breathe. In the battle against nature, there is no next time. There is only success or failure. Unfortunately, some get lost or go missing on their way back home. The final destination of the salmons that made the life-threatening journey is up the icy ravine. The closer they get to their destination, the shallower the stream becomes, making it harder for them to swim. It is a difficult obstacle for the salmons that swam back to their home without any food or break. For every salmon spawning season, the grizzly bears travel to the upper stream and go salmon hunting. Salmons exhausted from a long journey are easy prey for the bears. It's this cub's first hunt. It's an easy success. It's a feast for the bear family. But for the salmons that risked their lives to come here, it's a devastating end to their hopes of breeding. After a long and difficult journey, the salmons finally arrived at the spawning ground. But it isn't over. A battle that is even fiercer than the one they've just survived is waiting for them. After picking the spot to lay her eggs, the female cleans her nest. As long as she can breed, she doesn't care about the pain or the scars. The floor looks the same everywhere. But that's not true for the female salmons. They fight hard to win the best spot. They traveled here together, but when it comes to breeding, there is no room for being considerate. And it's not just the females that must compete. The males fight amongst themselves to win the females to bear their offspring. They must be quick-witted to succeed in breeding. Even if a female is taken by a powerful and ferocious male, another male can release his sperm when the female lays eggs to gain success. But the female only pretends to lay eggs, as if taunting the male. He tries again without success. He just wasted his energy. Anxious, the male urges the female to lay eggs. She gets into position. Will they succeed this time? Finally, the female releases her eggs. The male successfully fertilizes them. Rosy, beautiful eggs. They are the treasures the salmons earned after a long and rough journey. The female's job isn't over. She covers the eggs with pebbles with her tail to prevent them from being eaten by other fish or carried away by the current. She does everything she can until the very end. Salmons don't eat or rest when they spawn. And they lay about 3,000 eggs each. Only reproduction matters to them. Salmons that succeeded in breeding against the harshest of environment. Death is the next step. But this isn't the end. It's a new beginning. Because they won the secret war of reproduction. Organisms live in different habitats, but they all do their best to adapt to their surroundings for the purpose of reproduction. Evolution toward more stable and successful mating and reproduction continues. Genes inferior for the purpose of reproduction get weeded out. The desire to obtain healthy genes drives organisms to seek healthier, more attractive males. Brightly colored mandarin fish. Is it the flashy appearance? They spend most of their time hiding in the coral. And that is why protecting their territory is important to them. Competition becomes fierce among the male mandarin fish during the mating season. When there are male intruders, they become very aggressive. However, it's different for females. The male swims around her gently wooing her. If the female joins him, it means she's accepted him. They're floating up with their bellies side by side. The mating is a success. Without competition, organisms don't get the chance to breed. The future belongs to those who win. Nature is a fierce and ruthless battleground for survival. And the force that drives Mother Nature comes from the trials and efforts of the organisms that won the invisible competition. For a very long time, organisms have survived by overcoming life-threatening obstacles. The ones that fail to adapt disappear. And only the strong ones are selected by nature. The secret war of reproduction is the key cycle that holds the laws of nature together. Surviving the turbulent times, countless organisms continue to reproduce even today. They want to be the final winners in the secret battleground of survival.