How Wild Things Woo: Love, Lust, and Legacy in Nature | Full Documentary

Sex is at the heart of everything. It's the only real way of leaving a legacy in the genes of the future. It drives touching courtships and fierce battles. Without sex, there's nothing. But there's more than just the act, it's the build-up to it, when wildlife shows its incredible diversity. Hormones and sex drive are forces that shape behaviour and can change animals' purpose and persona. This is how wild things get sexy. Sex is a driving force for all over nature. The act of sex is mostly to make babies. But let's face it, it's foreplay that really counts. It brings out the best and the worst in the animal kingdom. Precoital courtship can give pleasure, but also gives the participants the chance to check each other out and make sure they've found the perfect match. It affects us all. Birds do it, bees do it, or in this case, love-struck swans and pond skaters. If they've found the right dancing partner, then begins the act of passion. The mute swan dunks his date. These pairings will result in eggs. Laying eggs are, by definition, the reproductive technique of most insects, fish, amphibians and reptiles. As the setting sun paints a romantic atmosphere, one community creates some mood lighting. Fireflies mix chemicals in their abdomens, causing a reaction that gives off light. How light is used varies between the 2,000 glowing species, but males and females flash to attract one another. The chemical Morse code creates some of the greatest firework displays in the natural world. Not all lovers need the lights off. Every summer, damselflies emerge from ponds and streams. To fulfil their destinies, they must dance. The males out-compete each other to try and lure females to their patch. A suitably impressed female signals her desire. Their mating requires some careful choreography and a good sense of coordination. In a position so weird it wasn't even covered by the Kama Sutra, he takes hold of her head with claspers on his tail. The female will then collect a sperm package from his underside to fertilise her eggs. Some clingy males keep hold of the females while they find suitable places to attach their eggs to pondweed. Other males let her go to get on with her work, but hover overhead to guard her from other potential mates. There's no intercourse, so not much fun, but importantly, eggs are safely laid and a genetic legacy passed on. There are many strategies to maximise breeding output. Many insects have short lives and need to breed before they are picked off by predators. Few have the challenging deadlines of insects like mayflies. They and their cousins emerge in one coordinated mass, a mist of mayfly. More mayfly emerge through the surface and join the bug ballet. They might have been living as larvae underwater for months or years, but as majestic adult insects they have only one day, a mere 24 hours. The more insects that swarm, the bigger the crowd that follows to eat them. There's no time to eat or drink, only to make the next generation of flies. But the flies make love, not war. With their one day of pleasure, they redefine group sex. Spent, but hopefully happy, they go out with a bang, leaving a lake full of eggs that will hatch and feed other animals next year when they dance again. The fish gorging on the insects are on a mating marathon themselves. Char climb their way through river systems to return to the place where they themselves hatched out. As fish gather, so too do predators, hoping for an easy meal. Despite the dangers, the fish keep going with singular determination. They want sex. In their case, it's not so much sex as spawning, and once they reach the quiet reed beds where they were born, the spawning can begin. They try to do most of their spawning under a starry sky, not for romance, but because fewer predators are active at night. They release clouds of eggs and sperm to drift together in the current. The sticky fertilized eggs will settle on pond weed and begin to develop. All fish have different kick-off points for their little ones. The river chubs decked out for the breeding season with a warty face. He's beautifully ugly, but if his distinguished profile doesn't attract the ladies, perhaps his building skills will. He's got strong, rubberized lips. They could make him quite a kisser, but they too enable him to shift rocks. He's building a nursery. He hopes a female might want to lay her eggs here. The stack of rubble creates pockets under the rocks, mini forts where her eggs will be safe. But it's not females that spot his handiwork. It's a dozen other species of minnow, all wanting to be king of his castle. They're not looking for ownership, just a place to drop off the kids. They use the chub's pad like a cheap motel. They drop in, flirt, spawn and leave. The chub's hard work will benefit a huge variety of baby fish. Despite the predators and freeloaders, few fish face challenges head-on like salmon. The fish have spent most of their adult life out at sea, but that's not where they started. They were born high up in fresh water streams, and now, ready to breed themselves, they must return. Obstacles come in all shapes and sizes. Millions of fish are in the mood. They can't ignore the urge to breed. But with so many fish crowding into a tiny river, word soon gets out of a fish feast. Tons of grizzly bear needs a lot of feeding. But even though each giant might snatch dozens of fish every day, millions more will make it through the entourage. Hundreds of kilometres later, they reach the shallow gravel beds where their own lives started out. Many species make their own journeys. They all start out looking like typical silvery sea fish, but during their migrations, they've changed. Fuelled by hormones, they've become bolder colours, and the males have developed fearsome teeth and hunchbacks. The female makes the bed, a shallow pit, for her eggs. But even now, when they're ready to get intimate with each other, the intrusion doesn't stop. It's a grizzly end, but not just for bear victims. All the salmon are coming to the end of their lives. This is the 11th hour, and they must breed now. Males nip at each other, fighting for the best spot of the female's side. The female keeps the nursery in good shape while she's watching the competing males. Ultimately, she'll announce the winner. A male nibbles affectionately at her side, and he's scored. She releases eggs by the thousands, and he's in the prime position to fertilise them with clouds of sperm. But although this is the hottest date of his life, the male's not looking his best. Though they're born to freshwater, as salmon mature, they become saltwater fish. Weeks in the freshwater streams are destroying their bodies, already weakened by the trauma of migration. For this entire generation of fish, time's up. But theirs is perhaps the greatest example of the power of sex. They've given their all. Their rotting bodies will feed the forest animal community and enrich the soils, keeping the habitat in great health. They're fertilising the nursery for their children. For these little ones, the epic journey will soon begin. To find their way out to sea, until their sex drive forces them to return. Fish and many other groups of animals are egg layers and don't have actual sex, but that's not the case for mammals, who like to make a big fuss about mating. Even the cutest of creatures turn into sex-crazed beasts. On the far side of the world, frightening bellows echo across Australian eucalyptus forests. Everyone loves koalas, cute and cuddly teddies. Well, in theory. But now it's the mating season. With hormones surging through his veins, the male bellows, calling out for females and warning males to stay off his patch. Males will fight fiercely, but perhaps he didn't expect this female to fight back too. He may be barking up the wrong tree. Koalas rarely come to the ground, but a horny koala isn't afraid of a bit of climbing. A bald patch on his chest has a stinky scent gland, so as he climbs, he's leaving a musky trail, telling other males he got there first. Maybe this female's a better bet. The female's clearly protesting, but he's not taking no for an answer. There's nothing subtle about koala courtship. This is more rape than romance. His sharp claws lock into the bark, meaning he can trap her in his arms against her will. He's going in. Or so he thinks. Marsupials really like to get weird in the bedroom. The male has a two-headed penis, but that's just as well. The female has two separate vaginas to match. It sounds like a recipe for fun, but females rarely seem up for it. The males usually take them by force, though this female's fighting back. She's much lighter than him and climbs to the thinnest branches to get out of reach. The koala sex maniac is exposed. But he's not the only mammal with sex on the brain. High in the Andes, a guanaco, a wild llama, stands guard over his herd. Here, males win mates by proving their worth as good providers. He's fought hard with other males to secure and defend a good patch of mountainside, rich in grazing and with good lookouts to watch for danger. It's everything a female guanaco could want, and they line up ready to start a family on his patch. Theoretically, he'll mate with them all. That's as long as another male doesn't show up. His work is never done, and when he picks up the scent of an intruder, it's a call to arms. Once again, he must defend his honour. They don't have obvious weapons, but male guanaco do have enlarged canine teeth to nip at their opponent's heels. They also spit, chase, ram and wrestle. Our male emerges victorious. After such an impressive display defending the home, he doesn't have to do much to win a female's affection. Though he loses marks on his dismount. Mission accomplished. Thanks to his hard work, he can mate with all the females in his territory. Though this is the real prize. The chance to leave a genetic legacy. He's father to the next generation, a payoff that drives most sex in the wild. Like father, like son, the little ones are already practising their moves, hoping one day to have a harem of their own. It will be a couple of years until they're ready to play in the mating game. Then cute and fluffy can become big and angry. Such is the power of hormones. The fourth biggest land animal, a hippo heavyweight, is quite a contender in the sexual arena. Hippos live in groups called pods. Only one big male holds command of a stretch of river and mates with the many females that gather to enjoy it. He doesn't like competition. And when another male turns up, it can only mean one thing. Males allow only younger bulls to stay in the group and they must bow to him. Any who are not submissive will face his wrath. An adult bull can be a ton and a half of trouble. Hippos have a way of marking their territories that's hard to miss. As they poop, they wriggle their short tails. It hits the fan. This muck spreading covers their patch of river with their scent. If the signs are ignored, a boundary dispute begins. The bulls can open their mouths 180 degrees to show off half-metre self-sharpening teeth. Hippo bulls have been known to die from a tusk stab, so they try and use gesturing to avoid violence. It doesn't always work. Put in his place, the intruder leaves before things get out of hand. Not all mammals are as well armed, but that doesn't mean they won't fight. A big Australian fellow is also willing to fight for his females. A rusty red male kangaroo tickles a female's tail to try and get her in the mood. But here in the bush, there's stiff competition. Boxing, including kickboxing, sorts the men from the boys. These young fellas are still climbing the ranks. They're dwarfed by the big reds. These are heavyweight fighters in their prime. They've been to the school of hard knocks. It doesn't take long to sort out who's top dog. The biggest and most powerful male will father the youngsters in the area. But while the boys are impressive, the females are nothing short of miraculous. They're breeding machines. A female like this has a joey who's left the pouch but still hangs around to drink milk. A little pink joey permanently carried in her pouch and another fertilised embryo inside. She's paused its development until there's an opening in the pouch. She's a kangaroo production line. Most mammals fight for mating rights, but not all offer such a quick turnaround. In the Australian outback, there are some exotic travellers. Dromedary camels, introduced from Arabia and now roaming wild. These ships of the desert live in small herds. A single large bull and his mates. Of course, other bulls try to muscle in. A competing male gurgles and foams at the mouth. But his real party trick's to turn his soft palate, the fleshy part of the roof of his mouth, inside out. A grotesque resonating chamber that vibrates with his love songs. Strutting side by side, the males size each other up. Only one will get the chance to mate. When the ships are rocking, don't come knocking. They have spectators, all looking to hump. When it comes to wild sex, mammals are amazing. But it's the birds that are the real showstoppers. And never more than in the wilds of India. Young male peacocks watch a group of females, like teenagers out on the pool watching girls. They strut, trying to win some favours. But they've yet to grow full adult plumage. They stand no chance when the big boys arrive. When he vibrates the tail, feathers seem to purr, and the eye markings become hypnotic. Who could resist? The ability to strut around shaking these impressive tail feathers will tell the females that this male has strong genes and is therefore a worthy mate. Many birds go to great lengths to show off this genetic prowess. Not monsters in the mist. Great bustards, among the heaviest of all flying birds, gather to show off. Their voices are not beautiful, but do demonstrate the birds' volume. The deeper the voice, the bigger the chest. The next step involves feathers, and the males seem almost to turn themselves inside out, puffing themselves up with air. The airbags amplify deep calls. The booming bustards can be heard from great distances on the open plains. It's weird, but it works, at least on female bustards. There's another more familiar featherweight with a similar trick. The king of the strutters. He doesn't have the peacock's colours or the bustard's boom, but the gobbler makes up for it with persona. He can make 30 different sounds, but the gobble can be heard a kilometre and a half away, and it's a call to arms. Turkeys are polygamous, meaning that males compete for access to a group of females. Known as toms, the male's pink heads can flush a patriotic red, white and blue. He has over 5,000 shimmering metallic feathers, though only 18 make up the tail fan. He provocatively dangles his snood, the tube of skin hanging from his beak. It's erectile. He can make it longer or shorter, and it turns out length is everything. A long snood means the tom's healthy and the girls can't resist. And armed with cowboy-style spurs on his legs, this wild western is not afraid to fight. Time for a showdown. Birds can make quite a song and dance over sex. Water birds especially enjoy a synchronised swim, the best of buoyant ballet. Many of these birds are faithful for a long time, courtships vital to make sure they're in sync. Gifts help, like a birdie bunch of flowers. In terms of making an effort, the most desirable bachelor might be a bird of paradise. In this case, an Aussie, the Victoria's rifle bird. At first glance, not much of a hunk. He's watching an even plainer female. He announces his arrival on the stage. He's a natural-born showman, hoping to wow her with his mystique and masculine moves. The disappearing head act. There's magic in the air for the star-struck female. She just can't get enough. He's scored for sure. Birds go all out on foreplay, though you sometimes have to wonder if it's worth it. There's a lot of effort for very little reward. A wham-bam thank you, ma'am. And it could be quite a strain in terms of acrobatics. Some make up for it with quantity over quality, or bribe their way in with treats. A South African beach is the perfect place to relax and get romantic, as long as you don't mind being watched. South African, or jackass penguins, are the faithful type. They carefully select a mate and return it to them. They return to their breeding beaches to breed together, year after year. Despite voyeurs at every turn, they try to find a secluded spot to make out on the beach. Then to find the perfect home. He doesn't carry her across a threshold as much as guide her. They consummate their love. Then he brings a few found treasures to make it homey. They'll be wedded to this patch for about four months while eggs hatch and chicks are fed. Both will take turns looking after the infants. While one's babysitting, the other swims off to feed. Raising babies as a couple is hard work, so some recruit helpers. Australia's most loved bird, the splendid fairy wren, has a sex life worthy of a daytime chat show. The drab female's promiscuous. She plays the field. And when her babies hatch, the males are left in a dilemma. There's no DNA testing for them. They each assume that the kids are theirs and provide child support. For this modern family, multiple dads means the chicks stand a greater chance of being fed and protected. The best possible start in life. Many small birds have impressive sexual stamina. They may mate dozens of times each breeding season. But for staying power, the mammals are high performers too. If any animal knows about sex, it's the lion. This king of the beasts is also king in the bedroom. A couple may go at it four to six times an hour for days on end. There's a saying for couples that have a lot of sex, that they go at it like rabbits. But perhaps that should be at it like bonobos. It's a primate that's the true king of the swingers. Many animals have sex purely to make babies, but there are other reasons. Bonobos are small cousins of the chimpanzee, and they have mastered the art of pleasure. In the privacy of the Central African rainforest, they have sex a lot. Everyone has sex. Males on males, females on females, grandma with grandson, brothers and sisters, anything goes. Obviously, they mate to make babies. But they also use sex to make friends, to beg for food, to reassure one another, even to make up after a fight. Sometimes the induction into their vivid sex life is traumatic. An adolescent wants to show a younger male how it's done. The little ape's clearly not in the mood. He runs back to mother, but to comfort him, she offers some sexual pleasure too. These primates live by the rule, make love, not war. They're the least aggressive and violent of the great apes, and have substituted wild sex over conflict. They've discovered that sex doesn't have to be purely for mating. It provides pleasure as well. And let's face it, they're not the only ones.