Wildest Indochina | Episode 4: Vietnam - Phoenix from the Ashes | Free Documentary Nature

Vietnam, one of the most biodiverse countries on the planet. Approximately 10% of the world's species live here. Tropical jungles burst with wildlife, but less than 50 years ago things were very different. Vietnam's forests were decimated as a battle between people became a war against nature. The dust finally settled and remarkably life fought back. Even today new species are being discovered at an incredible rate. These forests had their own secret weapon and like a phoenix from the ashes this savior continues to rise. Vietnam is the easternmost country on the Indochina peninsula. It stretches approximately 1,600 kilometers from north to south and is just 50 kilometers wide at its narrowest point in the center. Despite having an extensive coastline, three-quarters of the country is hilly or mountainous and around 40% of the land is covered by forest. During the Vietnam war rainforest cover proved to be the best weapon against enemy attack. U.S. forces sprayed around 72 million liters of herbicides including Agent Orange on the Vietnamese countryside and dropped an estimated 13 million tons of bombs. Hundreds of tree species were killed off. Around 20,000 square kilometers of forest was destroyed. 20% of the total cover. Animal casualties ran into the millions. The devastation was so massive that the terms ecological warfare and ecocide were coined to describe it. But as soon as the guns fell silent one remarkable species immediately set about regenerating the land. Bamboo is the fastest growing plant in the world. In just 24 hours it can attain a height of up to a meter. The taller it grows the faster the rate. In a matter of days it can tower above trees that have been established for decades. Essentially a giant species of grass, bamboo grows in every part of Vietnam. It plays a key role across the entire ecosystem and many species rely on it for survival. The lowland tropical forests of Cat Tien National Park in southern Vietnam are home to some of the most haunting sounds heard anywhere in the world. The upper canopy provides the perfect vantage point for one of the world's most operatic primates. A creature fueled by a diet of bamboo. Yellow-cheeked gibbons mark their territory using loud noises rather than physical signs. Each morning adults produce song bouts to warn neighboring groups to keep their distance. These vocalizations can be heard more than three kilometers away. Gibbons employ the same vocal technique that professional opera singers take years to master. By singing soprano they're able to put much more power behind their calls with minimal effort. With dawn chorus over this female and her two youngsters can relax except after a good night's sleep all juvenile gibbons want to do is play. Yellow-cheeked gibbons are born with blonde fur but at around two years of age this changes to black. Although males retain this dark coloration for life females return to their natal blonde once fully mature. Forty percent of the Cat Tien region is bamboo forest. Combined with canopy piercing trees it's the perfect place for energetic youngsters to show off. Gibbons are the best brachiators or swingers on the planet. They can reach speeds as high as 55 kilometers an hour and swing up to 15 meters from branch to branch. Playtime over. The eldest youngster decides it's time to rest. Hanging by one arm is a common way for gibbons to relax. Long fingers and powerful limbs enable them to hold on for over an hour without letting go. Breakfast is a whole morning affair. Fresh bamboo shoots are a particular favorite. Although fruits seeds and leaves make up most of their diet gibbons also indulge in insects and even the occasional bird's egg. Opposable toes allow their feet to grasp in effect providing a second pair of hands. However this youngster is still getting to grips with the smooth surface of bamboo canes. Yellow-cheeked gibbons spend most of their lives in the upper canopy and rarely venture down to the forest floor. And there's good reason. Ground level is the realm of predators and this low-flying novice has company. The mother suddenly recognizes the danger. She rushes to the scene. She guides the potential victim back to the safety of the canopy. Asiatic black bears might be excellent climbers but they're no match for the jungle's greatest gymnasts. Although similar in size to their American counterparts, Asiatic black bears differ by having a cream-colored crescent across their chest. Thicker fur up to 15 centimeters long around their face and neck is another distinguishing feature. Despite being armed with three centimeter curved claws and flesh-tearing teeth this predator is mainly vegetarian. Grasses, berries and roots make up the majority of its diet. However, along with the odd mammal, insects are a particular delicacy. This nose is capable of detecting honey from a distance of five kilometers. Ants just a few body lengths away stand little chance of not being discovered. Midges are a constant irritation in Vietnam's hot, humid jungles. So after washing down his meal with a smear of sticky tree sap, this male decides to cool down and indulge in some temporary bug relief. Asiatic black bears lead a mainly solitary life in a territory covering up to 40 square kilometers. In order to attract females and let other males know they're on someone else's perch, this male begins to scent mark certain trees. It's also the ideal way to relieve an itchy back. But this male's daily ritual is suddenly cut short. Another male has ventured too close in company. The visitor soon gets the message that this is one opponent not to be messed with. To escape danger, black bears either run away or head up trees. Choosing the latter, this individual has no choice but to sit it out. It could be hours before you feel safe to come down. The ideal excuse for a mid-morning nap. 17% of Vietnam's forests are made up of bamboo. This fast-growing plant continues to play a key role in regenerating many different types of ecosystem. Alongside rivers and streams, bamboo roots knit and hold the fragile bank soils, which would otherwise be eroded away. It also helps keep tropical waters cool by providing shade, beneficial to aquatic creatures. During cooler times of the day, turtles bask in order to raise their body temperature. This increases their metabolism, aids digestion, and encourages them to feed. Fish, insects, plants, and fallen fruit make up the majority of their diet. However, one particular species has taken to hunting exclusively on land. Keeled box turtles get their name from the three large keels, or ridges, running along their upper shell. Fully grown, they can reach around 18 centimeters in length. Partially webbed feet indicate a much more terrestrial lifestyle, as opposed to an aquatic one. This individual spends most of its life in the forests, rooting through leaf litter in search of a mulch-munching prey. Earthworms play a key role in the fertility of soil. Just one square meter of forest floor can contain over a thousand of these nutrient-producing invertebrates. For any species of worm, raising your head above the trenches is asking for trouble, especially in box turtle territory. This reptile may have fairly poor hearing, but its full-color eyesight and sense of smell are excellent. Like a cheetah chasing an antelope, the odds surrounding this outcome appear fairly evenly matched. Despite being one of the slowest predator-prey encounters on record, for the turtle, it's one of the most rewarding. This meal is over 80% pure protein. The bamboo in Vietnam's forests generates up to 35% more oxygen than equivalent stands of trees. But despite its rapid growth rate, certain younger plants mysteriously disappear. This isn't the work of an oversized earthworm. It's the modus operandi of a specific ground-dwelling mammal. Bamboo rats weigh around four kilograms and can reach up to a meter in length. They spend their entire lives digging tunnels under the forest floor to access the fresh roots and shoots of their favorite food, bamboo. Once located, the stems are cut free and dragged underground. This female's almost vertical incisor teeth are so large they remain uncovered by her lips. Her sense of smell is so acute, she can detect any fresh growth through the compact soil. Powerful claws assist her oversized teeth whenever excavating new tunnels. Bamboo rats can have as many as eight offspring in a single litter, up to four times a year. These youngsters are just a few weeks old. They're already developing a taste for the succulent stems. Despite the bamboo rat's vast distribution and fast-expanding population, here in Vietnam, they're unlikely to run out of food anytime soon. Bamboo has a tensile strength greater than mild steel. It's even tougher than carbon fiber. Despite these incredible physical properties, bamboo is made up of a series of hollow stems. These pockets provide the perfect refuge for any creature small enough to fit in. The hole in this section of stem was initially bored by a beetle. However, a very different animal has since taken refuge inside. This bat is no bigger than a bumblebee, weighing slightly more than a paper clip. It's one of the smallest mammals in the world. The entire colony of up to 25 bats manages to squeeze into just one small section of bamboo stem. Home life is cozy. Barely a week old, these babies are already almost as big as their parents. Feeding such a first-growing brood is no easy task. Each night, just after dusk, the mums head out to hunt. Termites are a particular favorite prey. Back in the roost, the young bats capitalize on the extra space to prepare for a life on the wing. Bamboo bats may be small, however, in such large numbers, they provide a decent meal for a relatively small snake. The baby bats are unable to escape, but this predator has no way of getting in. The entrance is thinner than the width of a pencil. The snake abandons its ambush, and the mother bats return. Flattened skulls allow them to just squeeze through the tiny 4mm-wide slit. In around two weeks' time, the babies will take to the air themselves, and eventually, will find a hollow bamboo home of their own. Ha Long Bay, in northern Vietnam, lies in one of the largest limestone regions in the world. 400 million years ago, tectonic activity raised underwater bedrock above the level of the sea. Once exposed to the moist tropical air, carbon dioxide, carried by rainwater, slowly dissolved and sculpted the limestone rock. The result is a land of bizarre-looking formations, a landscape geologically known as karst. Ha Long Bay contains more than 1,600 limestone islands Many are much taller than they are wide, making them uninhabitable, and too precipitous to explore. However, a large number are known to contain secluded beaches, sea-cut grottoes, and extensive caverns. This region is home to some of the biggest caves in the world. Hang Toi, also known as the Dark Cave, is over 5km long and 80m high, tall enough to house a 25-storey building. Spectacular stalactites and stalagmites adorn the roof, walls, and floor. Droplets of water, seeping through the porous stone, deposit tiny layers of calcite above and below. Over time, this creates a labyrinth of primitive structures, some even joining to form calcite columns. Like the majority of limestone caves, Hang Toi was initially formed by a supersized underground river. Mildly acidic rainwater, seeping into the rock, continues to dissolve it. This creates numerous cavities, which, over time, grow and eventually link up. Surface rain, channeled through these interconnected drainage systems, creates vast underground waterways. This powerful river has no obvious source. The immense volume of water suggests a potentially even larger cave system than those already known today. During the Vietnam War, local people used the region's mainland caves as bomb shelters. They also provided refuge to one of the world's rarest primates, which still inhabit the region today. Hattin langurs were first discovered in the 1960s, but completely disappeared following the war, assumed extinct. But 30 years later, a small population living amongst the karst caves and limestone forests came to light. There are thought to be around a thousand living in the wild today. Langurs rarely come to the Like other leaf-eating monkeys, they lack cheek pouches in favor of a more complex multi-chambered stomach. This requires topping up on a seemingly continuous basis. Fleshy, immature leaves are preferred. This reduces the need to drink. The grown-ups in this group take a break from feeding and indulge in a spot of mutual grooming. This back-scratching not only reinforces social bonds, it's the perfect way to relax. However, the younger members of the group haven't yet grasped langur society etiquette. The only way these bundles of fur know how to unwind is a game of monkey tag. As dusk draws in, the langurs return to the safety of their limestone refuge. These caves and crevices not only provide shelter against the unpredictable tropical elements, as the seasons change, they remain at a constant, comfortable temperature. Although it was first assumed that many of Vietnam's animal species were wiped out during the war, over the following years, scientists have been astonished by what they've found. Delacour's langur had been presumed extinct for nearly 60 years before the Vietnam War had even started. Remarkably, it had survived, also utilizing the safety of limestone caves like its cliff-dwelling cousin. It's thought that only 200 or so of these langurs exist in the wild, making them one of the rarest primates on the planet. Along with previously known creatures that have resurfaced from Vietnam's ashes, brand new species are also being reported today. Until very recently, no new large mammal species had been discovered anywhere in the world for more than 50 years. This antelope, known as a saula, had been unknown to science prior to being captured by a naturalist's camera trap in 1992. This fueled further expeditions into Vietnam's unexplored territory. And, just a year or so later, this giant muntjac deer was also added to the new species list. It isn't just mammals that have survived the ecological ravages of war. Around 850 species of bird still call Vietnam their home. Scarlet minibirds and nectar-feeding sunbirds add color throughout the jungle terrain. However, one feathered resident shines like a neon beacon in Vietnam's northern mountainous range. This pheasant, known as a tragopan, is only found where bamboo thickets or rhododendron bushes are common. Although solitary by nature, this male has spotted some potential company. Male Teminx tragopans are one of the most conspicuous birds in the world. It's the mating season. This individual does everything he can to impress. As part of the display, he inflates his horns and multicolored wattle to appear powerful and robust. But this female seems unimpressed, or she's just playing hard to get. Either way, it seems this game of peekaboo could go on for days. Approximately 70% of Vietnamese people are farmers. 25 million of these are reliant on forests for survival. The carpet bombing campaign during the war wiped out entire valleys. Of those trees left standing, many were bulldozed to the ground. Not all bombs had a negative effect on the local community. After landing in smaller lakes, the explosions deepened the lake beds, doubling the fish harvest over time. In rice paddy fields, the explosions often compacted the soil, leaving behind leak-proof crater ponds, some of which still pay dividends today. Once stocked with fish, these mini lakes provide a replenishable source of protein. They've since become favored sites for houses, the pond being the epicenter of new communities. Bamboo fishing rods come free with the terrain, and it seems this remarkable plant plays a key role in the lives of people too. As well as being the key building material for boats, and the majority of rural houses, bamboo is also a nutritious high-protein source of food. Not all of Vietnam's forests were affected by the war. Certain areas have even benefited from having a continued military presence for the past 40 years. Son Tra Primary Forest on the Da Nang Peninsula is one of the last refuges for perhaps the most beautiful monkey in the world. Red shank dukes used to be found across the majority of Vietnam. Relying mainly on leaves and fruit to survive, they suffered badly during the defoliation campaign of the war. This colorful primate is actually classified as a langur. It also has a multi-chambered or sacculated stomach to break down the tough plant cellulose in its diet. Gassy digestive byproducts give them a constantly bloated pot-bellied look. Standing approximately 75 centimeters tall, red shank dukes are relatively large monkeys. Their tails are as long as their bodies, providing excellent balance when leaping through the canopy. They almost always take off and land feet first. Dukes are highly social monkeys, usually living in groups of up to 15 members. Unlike many other primates, there's very little color difference between females and males. Youngsters are born just slightly paler and attain full coloration at 10 months. Due to their conspicuous appearance, many red shank dukes became easy victims of military target practice. Even today, they're much sought after by the illegal pet trade. This particular population, however, have unwittingly been protected by the country's military. Until recently, this forest had been a no-go zone to the public since the war ended in 1975. Scientists assumed no duke langurs had survived in this region. How wrong they were. Around 200 individuals have now been recorded living on this isolated peninsula. They represent over 60% of the country's population. Vietnam's tropical forests are home to more than 5,000 different species of insects. There are approximately 1,000 different varieties of butterfly, more than the total found in Europe and Australia combined. Through pollination, insects played a crucial role in regenerating the forests during and following the war. They also provide a valuable source of protein for many creatures, including a rare primate that chooses to hunt at night. This pygmy slow loris more closely resembles a teddy bear rather than a primate. Its body is just 20 centimeters long and has virtually no tail. Muscular padded hands and feet enable it to cling on tight to branches. Oversized eyes provide excellent night vision. Unlike most other primates, lorises have a mirror-like layer behind their retinas that doubles the perceived brightness. This individual spots a potential meal. Bush crickets can't fly but can jump at incredible speeds. The two-handed attack meant the cricket stood no chance. Lorises are one of the few animals capable of eating while hanging upside down. Hunting at night means they avoid competing with other primates that share their territory. Lorises aren't the only nocturnal mammals in search of insect prey. Vietnam's moonlit forests are the domain of another insect-loving predator that's reminiscent of a giant shrew. Austin's palm civets are just over a meter long and weigh around three kilograms. Despite having feline characteristics, they're more closely related to weasels and mongooses. Fermented tree sap is a particular delicacy. Although excellent climbers, they spend most of their time foraging for insects and other invertebrates on the forest floor. Earthworms using the cover of night aren't as safe as they seem. They make up the bulk of this hunter's diet. Many of Vietnam's animals and plants suffered badly during the recent war. However, certain species make a living out of death. Like bamboo, this plant called an elephant yam thrives in secondary forests. Woodlands that have regrown following major disturbance. Known as the witch of the forest, she is about to cast her nocturnal spell. While the night temperature drops, the plant heats itself up by 10 degrees Celsius. Thermal imagery highlights the massive increase in warmth. As the outer leaves unfold, a cloud of noxious odor is released into the air. It's the smell of rotting flesh, an irresistible perfume to a creature drawn to death. Carrion beetles are scavengers that feed on the bodies of dead creatures. This time, however, they've been tricked. Once inside, the flower's slippery walls prevent the beetles from climbing out. There's also not enough room to spread their wings. It seems there's no escape. But the plant means no harm to its captives. Dawn arrives and the flower remains unchanged. The beetles are held prisoner for the entire day. But as the second night draws in, the witch of the forest completes her spell. Pollen, squeezed from the stamens, showers the captive beetles below. The plant's slippery internal walls suddenly take on a rough texture. Finally, the prisoners are free to go. The pollen-laden beetles make their escape, just as other forest witches are beginning to stir. Unable to resist their pungent aroma too, these flesh-seeking insects ensure pollination, playing a key role in life rather than death. Vietnam is a unique example of nature's inconceivable resilience. Years of war almost obliterated all forms of life, but the forests fought back, sheltering and feeding their residents. Many species were presumed forever lost. Instead, greater numbers arose from the ashes. One plant in particular led the way in regenerating Vietnam's ravaged land. It seems nature and its creatures, side by side, will always stand.