Wild Workers: Nature’s Unseen Engineers Full Wildlife Documentary
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From North American bison maintaining prairies to African migrations vital for grassland health, discover how wild creatures are the unsung heroes in the intricate cycles of life on Earth.
The Wild: How The Prairies Evolved Over Tens Of Thousands Of Years Of Continuous.
From master builders to interior decorators, bulldozers, and giant excavators, wildlife are the architects of engineering marvels. Indeed, what we call the wilderness is the home of billions of highly organized workers. For far longer than humans, and often on a much grander scale, animals have transformed our world. Every construction needs a solid foundation, and the heavy machinery to get the job done. This is the story of how vast herds create and manage their environment.
Supported by an army of landscape architects and dedicated gardeners, so immense are their efforts, the circle of life itself begins with these wild workers. Great, open plains. Covering a quarter of all land, they are carpeted in nutritious grasses, able to support the largest herds on the planet. North America's grasslands evolved over tens of thousands of years of continuous grazing by vast herds. In fact, the prairies would not exist without the bison.
With the largest amongst them weighing in at over a ton, a herd can consume 12 tons of fodder each day. A factory line of powerful tongues that wrap around and snap off grass in jumbo-sized mouthfuls. However, bison are fussy eaters, preferring the freshest shoots from the fastest growing species. By regularly mowing down these dominant grasses, the bison allow other species to flourish, keeping the prairie diversified and healthy.
The grasses the bison leave untouched provide biodiversity for many insects and birds. With the help of moose and reindeer, the bison also keep shrubs in check, and fertilize the soil with their manure and urine. As the herds are constantly moving, the prairies thrive with short periods of severe grazing, then long periods to recover. It's landscape gardening on a gigantic scale. Yet when the gardener disappears, the lawn starts to turn brown.
Two hundred years ago, widespread cultivation, and the near extermination of bison, reduced the prairie to 5% of its original size. Without the standing grasses left by the bison there was nothing to hold the soil together. Erosion and wind transformed the great plains into a dust bowl. Today, thanks to conservation efforts, bison numbers have rebounded, and the grasslands are recovering. Saving the prairie has meant protecting the animal that work as its caretaker.
African grasslands have a different imperative. There's a constant state of flux between the grasses and the trees. Enter the giraffe, an expert tree surgeon. Here, trees are important for food and nesting sites for many birds and other animals. They also provide much needed shade from the blistering heat. Yet if there were too many trees the plains would turn into a forest. That's where the giraffe steps in.
As the world's tallest living land animal, giraffes are the loftiest tree trimmers on the planet. A flexible tongue extends reach even further. Pruning some trees makes them produce more nectar, a boon for birds and insects. To get its fill, a giraffe will eat almost 30 kilos of foliage a day. They can prune a plant to within a millimeter of its life, and even kill some trees, keeping their numbers in check.
To survive the onslaught, many trees have grown spines and thorns to protect leaves even on the highest branches. Others contain tannins which produce a nasty taste. So giraffes not only prevent trees from running rampant, but have shaped the way trees themselves have evolved over time. Controlling trees in the world's jungles, however, is a near impossible task. With sunshine and rain fall year round, plants never stop growing, producing a tangled mess of vegetation.
Here on the island of Borneo, competition for limited real estate is fierce. It would take a giant to whip this chaos into shape. The Bornean elephant stands a half a meter shorter than its mainland relatives. But it's the heavy lifter in these parts. Led by the matriarch, the herd moves through the forest, breaking down trees and trampling plants underfoot.
Weighing as much as a large SUV, each adult is a walking demolition ball, on the hunt for up to 150 kilograms of food each day. As a unit, the herd clears the understory, opening up the forest floor, that would otherwise be choked with vines and small plants. They also create gaps in the canopy, and as sunlight reaches the ground, grasses are able to grow. Food for smaller grazers like bearded pigs.
Fruiting trees flourish with the extra sunlight, an even greater bounty. And in these elephant-made clearings, some of the jungle's tallest trees get a head start on their competitors. Indeed, without elephants, it's believed that some of the greatest tree species in Asia and Africa would disappear. The whole forest benefits from the demolition work of the elephants. Even at play, the herd pulverizes its surroundings.
Their daily bath is a time to relax, but their antics widen the river by compacting soil and removing large quantities of mud from the water. Elephants just can't help making an impact. With the games over, it's time to move on. The matriarch leads the way. The herd builds and maintains a system of trails that can stretch over tens of kilometers, a network of roads through the chaos of the forest.
So it is no surprise that on the opposite bank, the elephants find an opening in the undergrowth. The start of a jungle highway built by elephants. It's not necessary to be a giant animal to transform one's environment. As proves one leaf-eater from Australia. Found high up in the canopy, the koala is the only animal which exclusively eats the leaves of eucalyptus trees, the plant that dominates most forests on the continent.
Usually both koala and eucalypt live in harmony with one another, but sometimes this tree hugger can turn into a wood mill. Conditions in these dry Australian bushlands are tough. With less water, eucalyptus can't grow as quickly as trees in tropical jungles. Instead, they protect themselves by producing toxic leaves. A highly-tuned sense of smell helps koalas select leaves with the smallest amount of toxins.
They then spend hours grinding their food to a pulp before lapsing into a deep snooze to digest their meal. This usually slows down the koalas, and gives trees time to recover between pruning sessions. But in recent years things have begun to change. The expansion of human development has left only small pockets of habitat suitable for koalas to live in. So eventually there's not enough leaves to go around.
Along swaths of Australia's southern coast, koalas have stripped entire stands of trees. With few natural predators, koala populations can double within just a few years, overpowering the hardy eucalyptus. It's deforestation at the hands of one of the world's cutest and cuddliest animals. While the forest, in parts, may not recover, some koalas are now being relocated to save them from self-inflicted starvation.
The animals that eat leaves and grass keep plants in check, or, in the case of the koala, sometimes overdo it. But the creatures that eat fruits determine which plants even get to grow. In Borneo, macaques act as unofficial tree planters, unwittingly transforming the jungle as they move. Whenever they can find them, the troop gorges on fruits, which make up over 60% of their diet.
It's always a race to get to the best treats first, and squabbles often break out. The choicest selections devoured, the troop hurries on its way. They can travel up to two kilometers a day, carrying the fruits in their stomachs, and depositing the seeds they contain far and wide. The trees whose fruit they favor are planted throughout the forest, to the benefit of many birds and other mammals who also feed on the fruits.
However, the macaques can also stop the spread of other plants. When the monkeys eat too many flowers from one plant, they can prevent it from even producing fruit. So it pays for plants to grow tasty fruit, but not to put any attractive flowers on offer. Luckily this water hyacinth is a noxious weed imported from South America for its striking blooms. So the macaques can eat all they want of this floral arrangement.
In Australia, there are no primates to help plants disperse their seeds. But there is a giant bird who can get the job done. In the country's northern rainforests, the towering cassowary rules the roost. Second only to the ostrich, it is one of the tallest birds in the world, and the largest fruit eater in this neck of the woods. Trees with some of the largest fruits rely solely on the cassowary to transport their seeds.
It's the only animal with a gullet large enough to swallow the pods, and they consume hundreds of fruits each day. Once inside, digestive juices in the bird's stomach strip the flesh back to the seed itself, which is then deposited in a clump of humid fertilizer, giving it a head start in life. Without their avian ally, many seeds would fail to germinate. Some trees are more closely linked to the big bird than others.
The seeds of the endangered ryparosa tree germinate 92% of the time when they've passed through a cassowary, but only 4% of the time if they go it alone. So wherever the cassowary moves, it dramatically changes the entire structure of the rainforest. While some animals have a green thumb, other have had success in the earth-moving business. The Australian wombat is a subterranean excavator, who helps plow the soil down under.
Weighing as much as a large dog, wombats are one of the world's largest burrowing animals. Their warrens can comprise of 90 meters of tunnel. That's almost the height of the Statue of Liberty. Their homes take a lot of work to maintain, but wombats are born burrowers, with sharp claws and shovel-like feet. After cleaning up indoors, this female heads outside. It's the late afternoon, almost meal time. But first, she takes a dust bath.
Wombats can't sweat, so it's thought they turn the top soil to get to the cool layer of dirt underneath. It's the wombat version of a cold shower. But, in the process, she's shifting huge quantities of soil. It's a daily routine that is of particular importance to her home turf. Australia is the oldest continent on the planet.
Over millions of years, most of its mountains have been eroded away, and its soils have been leached of their precious nutrients. Tilling the ground improves soil health by mixing in organic matter and improving water penetration. It also helps spread fungi, important for plant growth, meaning more food for grazers like wallabies. Underground, the wombat's warren serves as a sort of water tank during heavy rain.
And by breaking up very hard soils, she helps trees to establish their roots. Although a bulldozer by nature, the wombat ensures Australian forests thrive. Even the oceans need their prime movers. When it comes time to breed, green sea turtles navigate their way, sometimes over hundreds of kilometers, to sandy shores and islands off the tropical coast of north east Australia. On a heavy nesting season, over 80,000 females arrive to lay their eggs.
After excavating a shallow depression, each female meticulously scoops out a small chamber for her eggs. Then she covers it all with sand. She leaves behind an area of 12 square meters of finely churned sand. During a mass nesting season, almost four square kilometers of sand is shifted and moved. Their work done, the excavators return to the ocean. As the young hatch out, the sand is shifted again, but each year many nests don't hatch.
The nutrients are absorbed by the dune vegetation, helping to stop erosion. Without the nutrients left behind by sea turtles, may beaches would simply wash away. The distribution of nutrients through every environment is vital for their health. Whales act as giant mixers of the seas. These humpbacks, like many whales, can feed at great depths, but they must return to the surface to breathe.
When they do so, over 40 tons of whale smashes through the water column, leaving a swirling tornado of nutrients and tiny microorganisms in their wake. Life is suddenly transported through every depth of the ocean. This "whale pump" is crucial, for most of the sea is a watery desert. Sparse patches of microorganisms, which all other animals in the food chain rely on, float like oases. But they are few and far between.
The whales not only help spread these nutrient-rich patches around, but fertilize the surrounding waters with their own urine and excrement. They're able to bring life to even the most barren waters. The organisms who benefit most are tiny plants, called phytoplankton, which underpin the entire marine food chain. Like plants on land, they harness the sun's energy to grow and release oxygen in the process.
Although smaller than the diameter of a human hair, phytoplankton are so numerous, they can form giant blooms which can be seen from space, and are responsible for producing 50% of the oxygen in the air we breathe. Rich in iron and nitrogen, the whale fertilizer helps keep these plants growing. In some coastal pockets, the ocean also has its own meadows. Seagrass is the only flowering plant that grows in the sea.
When it forms into giant fields, the grass helps slow down ocean currents, creating a calm haven for many animals to occupy. Like the North American prairie, these meadows have their own caretaker: the manatee. Sometimes called sea cows, they are ancient mammals, thought to have evolved from four-legged land animals some 60 million years ago. The manatee prize the network of fleshy stems at the base of the seagrass, called rhizomes.
Adults weigh around 450 kilos, and can eat a tenth of their own weight each day, as they punt along the seafloor powered by their strong tails. A herd mows down 90% of the grass. This intensive grazing actually improves the diversity of the meadows by allowing smaller and slower growing grasses to compete, and helps prevent seabed weeds from taking over.
Both the manatee and seagrasses have co-evolved over millions of years, and together help preserve the brilliant array of life under the sea. Along America's Pacific coast, some animals transport the nutrients of the sea to the forest. In spring each year, millions of salmon journey over 3,000 kilometers inland to spawn, returning to the same freshwater rivers where they were born. Waiting for them are hordes of grizzly bears.
Working hand in hand, these two animals will dump enormous amounts of fertilizer on the forest. But first, the salmon must make it upstream. It's a perilous journey, and the grizzlies don't make it any easier. After spending the winter in hibernation, some bears haven't had a proper meal in ten months. With so many fish in the water it should be easy. Most bears don't like getting their ears wet, so tracking a target can be difficult.
A high vantage point helps. And so does waiting for them where the salmon are most vulnerable. Finally, after their famine, the bears begin to feast. The waiting line of grizzlies is a gauntlet that must be run.compelled to swim upstream, the salmon labor on. After the fish successfully reproduce and lay their eggs, there is no return journey. Built for the sea, their kidneys are unable to cope with the freshwater.
The fish have slowly been dying for weeks. They end their lives in the very place where they were born. Their dead bodies flood the river with nutrients, providing food for their eggs which are about to hatch. This sacrifice is crucial, for, in the mountains, rivers lack many of the nutrients they carry further downstream. The bears, and many other animals, gorge themselves on the remains, helping spread the nutrition through the forest.
Eighty percent of the nitrogen found in these coastal forests comes from the seas, delivered each year by the salmon. Streams are transport highways for organisms and nutrients the lifeblood upon which most life on land depends. So the animals that change rivers impact all those who live around them. Africa's Mara river is so laden with sediment, its waters are stained brown. In charge of these murky waters are some of the world's largest civil engineers: . Hippos.
Although they graze on land during the night, a hippo must never stray far from the water. Their hairless skin dries out easily and has to remain moist to avoid dehydration. So during the day the herd wallows in the mud, resting and sorting out the family pecking order. Bizarrely, although hippos spend most of their life in the water, they can't actually swim. Adults weigh around four tons, and their round bodies aren't exactly streamlined.
Such is their size, the movement of the hippos carves new channels in the river and stirs up stagnant waters. So the nutrients the river carries continue downstream. They also contribute a huge amount of fertilizer of their own. Hippos produce up to 27 kilos of dung a day. It's so rich in nutrients it acts as a super food for many fish that also feed a great many other animals along African rivers.
The Mara river system is about to get an even bigger shake-up than a hippo belly-flop, however, as the great migration gets underway. Around two million animals travel across the plains of east Africa each year in search of fresh pastures. Most are wildebeest, but they are joined by more than a half a million Thomson's and grant's gazelles, and 200,000 zebra. This enormous herd transforms the plains as it makes a giant loop of the Serengeti.
The zebra are the vanguard, for they prefer to eat the tallest grasses. They knock down the canopy and open up the fresh shoots below for the wildebeest, who, in turn, are followed by the gazelle that mow the grass back to its roots. All fertilize the ground with their manure before moving on, ensuring the soil can grow a fresh bounty before they return. This annual cycle supports the greatest concentration of grazing animals on the planet.
But before the migration is over, the herds will give much more than their manure back to the ecosystem. A dangerous obstacle lays ahead, the Mara river. Nile crocodiles know the herds are coming and gather in anticipation. Like the Pacific salmon, some of the herd will sacrifice their lives. No one wants to be first. But the herds have eaten everything to the south. They must cross the river or starve. And the waiting hordes follow.
Wildebeest nervously track the zebra's progress. This time, the croc snatches only a mouthful of mane. Then it's the turn of the wildebeest. Like the zebra, they too must reach the northern grasslands. Finally, one must take the plunge, and risk everything. The floodgates open and a storm of wildebeest follow. Over days, tens of thousands of wildebeest must cross. Many will die as the crocodiles take their fill.
But the animals and the river all play a vital role in the health of the grasslands. Around 6,000 wildebeest drown each year, plowing over 1,000 tons of biomass into the river, releasing phosphorus and other elements important for plant and animal growth into the water. Insects lay eggs in the carcasses, creating food as they hatch for mongooses and ibis.
Fish get up to half their diet from wildebeest bodies, and the crocodiles put on enough fat to last them an entire year. The crocodiles can't get through all the carcasses alone. Many scavengers also congregate along the river banks. These carrion eaters do the dirty work of cleaning up after death. A flock of vultures can strip a carcass clean within minutes. They cooperate with hyenas.
The birds locating the meal, and the hyenas ripping apart carcasses too tough for the vultures to open. Although it's not an easy partnership. Often thought of as revolting and unclean, these death workers perform a massively underrated service. Without the rapid recycling of dead animals, reeking carcasses would litter the landscape, insect populations would boom, and diseases would spread. According to one estimate, vultures on the Serengeti consume more meat than all mammalian carnivores combined.
The nutrients scavengers consume are cycled quickly back into the soil. Here, another hard worker takes over. One that is, perhaps, even more important than all the rest. Dung beetles are obsessed with droppings. They locate a fresh pile by smell. Strong legs break the dung into tiny portions, and they begin to feed using specialized mouth parts. A pile of droppings is a fast food restaurant for several beetles at a time.
While they're chowing down, they help sink nutrients and moisture from the dung deeper into the soil, helping fertilize plants, and burying seeds caught in the droppings. The dung beetle is the end of the production line, and at the heart of a massive network of life. No matter how small or how large, the prime movers all ensure the health of grasslands and forests across the planet.
Death and decay are just one part of the rhythms of life. The constant movement of the herds, and the replenishing of the nutrients in the soils, ensure that the great cycle of life continues. Date: 2024-01-24
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