Wildlife Stories: Eat or Die | Free Documentary Nature

Eating provides great pleasure, similar to sexual pleasure. Although it's not as intense, of course. The lack of food is deadly, however. The lack of sex, well, no. Most animals have sexual relations once or twice a year. And although there are a few that eat only once a year, the general rule is to eat more frequently, even every day. And that, when it comes to sex, is a utopia. We're all on somebody's menu, and that's why the specializations that have developed in nature to savor each prey and each diet have evolved in such amazing ways. Snakes don't eat much. They have a slow metabolism because their body temperature is regulated according to the heat or cold of the environment around them. Since they don't need to burn calories to keep their body at a constant temperature, they can go without food for weeks or even months if they have to. And they never feel hungry. Their feeding instinct only wakes up when they discover a prey. That is, if they're not still digesting the previous one. This snake is using its sense of smell. It flicks out its tongue regularly at a steady pace and follows the route marked by the greatest concentration of aromatic particles in the air. It recognizes the smell as food and stalks its prey. The normal thing in snakes is to wait for the victim to approach and so catch it by surprise. But in this case, that won't work. This snake eats eggs. And eggs don't go wandering around from one place to another. You have to go look for them. The first thing is to make sure that the eggs are alive. Eating a rotten egg could be lethal. The egg's temperature is higher than that of the air, so everything is all right. Now it has to prevent the egg from rolling away. So the snake wraps its body around the egg to keep it from slipping away or breaking. This time it has found a nest with eggs that are five or six times larger than its head. But that's no problem. It can swallow even bigger eggs. The Dasypontes scabra has no teeth or very tiny vestigial teeth. Teeth would only get in the way. We don't know how, but it can distinguish between unfertilized eggs and eggs that are home to a developing embryo. And so normally it doesn't wolf down developing eggs. It doesn't want to kill the goose that lays the golden eggs, after all. Eating an egg with an embryo would also be more complicated, since after swallowing an egg, this species crushes it against some of the vertebrae in its neck. And once the egg has been perforated and broken, the snake can squeeze it to get out all the precious nutrients that otherwise no one else could make use of. This living lesson in ecology won't touch the rest of the eggs, even though it won't have abundant food like this until the bird's next breeding season. And some people don't appreciate snakes. Culturally, we have come to associate reptiles with danger, even evil. And often that has prevented us from seeing what extraordinary beings they are. The crocodilian order is prodigious in many ways. And as regards their feeding behavior, they are quite disconcerting. Some Nile crocodile colonies live in such isolated desert areas that nobody has been able to figure out what they feed on. It's believed that they eat very sporadically, perhaps less often than once a year. Caimans live in places with abundant resources. And yet they don't eat every day either. The birds that fish around them know enough to keep their distance. And the fish are quick swimmers. Caimans can only catch them when they take them by surprise. That's why their hunting technique involves stalking and waiting for an opportunity. Camouflaged, disguised as drifting tree trunks, or hidden among the floating vegetation, they patiently bide their time. Practically everybody recognizes the silhouette of a caiman, especially if it moves. And that's the reason why they spend so much time not moving, as still as a statue. Getting a bite to eat is hard when what you're trying to hunt knows that it has to be on the watch. What's more, caimans live in groups, but they don't share the little prey. So they also have to be on the lookout for anyone who might steal their prey. Their stomachs don't work regularly, so it's well adapted to fasting. And they also can eat just about anything, whatever crosses their paths, whatever it may be. If it moves and fits in their mouths, they won't turn their noses up at anything. Even if it's a poisonous fish. Caimans can't afford to be too picky about what they eat. And poisons are usually ineffective in the digestive tract. A little spicy, maybe, but that's all. Submerged under the caimans, there's an ideal habitat for an animal that searches for prey without being seen. It moves slowly, so slowly that its prey can't detect it. The mata-mata is a fearsome hunter of fish. Fish have a sensory organ called the lateral line, which detects all sorts of waves and water. But their lateral lines don't sound the alarm when this strange creature moves around. It seems like something lifeless floating in the current. It doesn't seem in any way dangerous. It's very stealthy and a great hunter. Its body looks like it's made out of wood. And its skin has uneven edges and folds that give it an irregular silhouette. It looks as if it's made of algae and water plants. Nobody's afraid of what looks like a piece of wood floating in these calm waters. Its head and long neck look like a rotten old branch. Its eyes are barely noticeable. And its mouth doesn't look threatening. It doesn't have a beak, nor teeth, nor serrated edges. Its mouth is just big, huge in fact. And it works like some sort of terrifying vacuum cleaner. When the mata-mata hunts, its slowness suddenly turns into an explosion of speed. And when it opens its enormous camouflaged mouth, it does it so fast that it creates a current that sucks water into its throat. Any fish passing too close by is doomed. Its movement is fast as lightning. Other fish swimming nearby don't even detect it. They're completely unaware that one of their companions has suddenly gone missing. Unfortunately for them, fish can't count either. They'll never know what attacked them. Because the mata-mata turtle is an extraordinary predator. These animals have opted for the opposite strategy to that of reptiles. Instead of alternating copious banquets with long fasts, they never stop eating. They spend most of the daylight hours gobbling down food or chewing it up. To obtain the energy they need to maintain their level of physical activity, these animals are forced to devour large quantities of greens. Not to mention the tough cellulose lining the walls of the plant cells. Some species require several digestion processes and several stomachs in order to break up all those cellular wrappings and reach the nutrients. A ruminant chews, swallows and digests a little, before then regurgitating that food to chew it all over again. A buffalo, for example, has to secrete more than 100 liters of saliva a day. But the biggest problem with a vegetarian diet is the huge amount of resources that the ecosystem has to supply to feed the herbivores, and indirectly, to feed the animals that eat them. In the dry season, some ecosystems run out of supplies, and the herbivores have to travel elsewhere to find new pastures. In some places, the feeding problems are really serious. There's not enough food to maintain the trophic network. The ecosystems are becoming too small, especially for the biggest species. An adult male elephant can consume up to 200 kilos of grasses and tree leaves a day. And in order to eat what it needs, it frequently destroys even more kilograms of vegetation than that which reaches its stomach. The ecological impact of these giant pachyderms is very worrisome. There are beginning to be too many elephants for the little savannah that we've left for them. We could say that the elephant is the species that produces the second greatest damage to the environment. But that's not true. In a natural way, elephants don't destroy the landscape. They do modify it. But by doing so, they prevent the bushes from taking over the whole ecosystem, for example. And that creates these plains where so many other species can live. And secondly, we are the ones who prevent the elephants from traveling freely along their old routes in the ancestral territories. Before humans began to invade Africa in massive numbers in the late 19th century, this species traveled along circular paths that ran from the savannas of South Africa all the way to northern Kenya. And years, even decades went by before they returned to graze in the same spot. Elephants gave the trees and bushes enough time to grow and renew themselves. There was a balance. Today, the elephants can't leave the national parks in search of food, because they are surrounded by agricultural development. Progress doesn't allow elephants to roam freely. Fortunately, the biggest eaters in the animal kingdom are the smallest creatures. A caterpillar forms part of the past of any butterfly. Caterpillars are butterfly babies, larvae the immature phase. To become a beautiful adult with colored wings and sexual organs, they have to eat. And eat a lot, non-stop. It's calculated that these larvae can devour and digest up to 86,000 times their own weight in plant matter. Which must be the world record for caterpillar food. But a glutton is someone who eats more than he should. And caterpillars don't eat so much because they're greedy pigs, but because they need to. A metamorphosis like the one that allows caterpillars to change into butterflies consumes a lot of energy. It requires storing a lot of nutrients, as well as very specific fats and proteins. The transformation of insects is a really amazing process that is still unexplainable. A living being makes juice of itself inside a hermetic container. And after a few hours, or months, or even years, according to the species and the climate, the liquid reconstructs itself into a new solid being, adopting a shape that is profoundly different from its form in the larval stage. Some insects, after going through their metamorphosis, no longer need to eat. Their only objective is to procreate. Many are even born without a mouth and die of exhaustion, sometimes just 24 hours after being reborn. This animal species is a unique case among living beings, and it's one of those insects that does feed itself during the adult stage. The females are vampires and only drink blood. Their mouths are like hypodermic needles, and they use them to puncture their victim's skin, inject anesthetics and anticoagulants, and then suck out the red juice of life with which to make more mosquito eggs. The male's diet, however, is completely different from the female's diet. The males search for the nectar of flowers, which is why their proboscis is so strangely shaped, full of protuberances to collect pollen. The female mosquito's gory feeding habits makes them one of the most dangerous animals on the planet. They are a terrible vector for illnesses, especially malaria, and so they are responsible for the deaths of millions of people. But mosquitoes attack every living being mercilessly, no matter how thick their skin. Their sharp, blood-sucking proboscis can perforate any epidermis. They even use to suck the blood of the dinosaurs. And they also know how to find the best spots on their victim's bodies in order to sip on their vital fluids. And in many places, they're a real plague. The trophic network, that is, who eats who, stays in balance because there are always animal species that prey on and control the populations of other species in order to keep their numbers within safe limits. If no one ate the proverbially prolific rabbits, these animals would become a serious problem for the vegetation, and the other herbivores in the ecosystem would be in trouble, too. This fellow is a rabbit hunter, although it also hunts lots of other things, too. The eagle owl is what's called a super predator. That means that it is so powerful that it can kill other predators. And so the eagle owl contributes in an extraordinary way to controlling the populations of the species that live in its natural habitat. If rabbits are temporarily a little scarce in its territory, then it eats more rodents or more foxes. And so it is that this owl is able to help keep the environment in balance. Today, however, it's not going to eat. It's already killed its prey, but even though it's very hungry, it's waiting for the dark of night to wrap everything up in shadows. It doesn't want anyone to see where it's going. Hidden where no light can give them away, the owl chicks are waiting for dinner. Their parents often dish out the food. But as the chicks grow, they'll start to settle accounts amongst themselves on their own. That's part of the learning process and of natural selection. Today, the largest one has decided that he has no reason to share. But that decision could kill him. The rabbit is too big. The owl's mouth isn't expandable like a snake's, and he could choke to death for being greedy. Sharing at his age would have been beneficial to him and his brother. He pulled it off, but that was very close. Swallowing prey without chewing them up first is a specialization that is exclusive to snakes and, well, as we've seen, to some overambitious owl chicks. Each animal has a mouth and a digestive tract perfectly adapted to its diet. The intestines of primates are more delicate than those of reptiles, and we have to send it food that is well processed by our chewing system, so that we don't suffer blockages or gases in our intestines. Since we're omnivores and can eat almost anything, we primates have a large mouth that can sometimes seem too large. A real big mouth, shall we say. And while not all of us are long in the tooth, young and old alike have lots of different teeth. Our teeth are very well differentiated for a reason. To eat plants or meat or seeds, some teeth have to cut, others have to shred, and still others have to crush and grind. But the thousand-and-one adaptations for feeding purposes can be seen particularly clearly in birds' beaks. This is a hammerkop and its very thick beak, a hummingbird and its much thinner beak, a stork and its longer beak, and this is a macaw and its hooked beak, the strongest of all beaks. Perhaps it is in their beaks where the evolution of the species is most evident. The impressive biodiversity among birds clearly shows us to what degree they modify, select and adapt their shapes, their techniques and their behavior. The part of the body that is the most essential for birds to be able to eat is also the best exponent of Darwin's theory of evolution. The crossbills are a particularly extreme case, the result of almost complete specialization. The crossbills have linked their survival to the cones of conifers. Here in southern Europe, above all to the maritime pine and its nuts, which are available all year round. As long as they don't disappear or no one chops the pines down, of course. With their twisted beaks, the crossbills have pretty much eliminated the possibility of eating anything else. But by taking that risk, they can eat something that no other bird can. They've found a niche in the market where there's no competition. Birds have the bad habit of eating on a daily basis. They can't withstand long fasts. Their metabolism is high because they have to keep their bodies very warm, like a human being with a high fever. And to do that, they have to burn calories constantly, which is why they're such frenetic feeders. The specialization of flamencos isn't found in what they eat, but rather in the size of what they eat and how they eat it. They live off a tiny crustacean, the Artemia salina. But eating things that are so little represents a pretty big handicap. If we humans had to feed only on small breadcrumbs, which we had to pick up off the floor with our fingers, there wouldn't be enough hours in the day to collect enough crumbs, and we'd die. To be able to feed on tiny things, you need to have some kind of super-efficient gathering tool. And that's what flamencos have. By opening and closing its mouth quickly and rhythmically, the flamenco filters the mud from the bottom and retains all the food particles it finds. But to get the most out of its filtering system, it has to synchronize the movement of its mouth with the movement of its feet, which stir up the muddy bottom. And that's precisely the origin of a dance and rhythm that is now famous around the world, and which bears the name of this bird. Flamenco means rhythm, art, and beauty, and its most fundamental step is a tapping of the heels. The spoonbill's specialized beak is apt for a more varied diet than that of the flamenco, although a spoonbill's meal also consists of small prey, and its food also hides in a similar way in the mud. But instead of stirring up the mud with their feet, the spoonbill sweeps its half-open beak through the mud in broad arcs. It has a very fine sense of touch, and when it detects something alive, it snaps its beak shut and quickly throws its head back to swallow its prey. Curiously, its tongue is very short, not even a quarter of the length of its long beak, so it has to eat like that. It's common to see them hunting in groups, which means that they help each other by driving the prey towards their companions. It's a kind of cooperation that is very rarely seen in nature. For example, cormorants certainly don't help each other at mealtime, and their table manners aren't exactly exquisite either. Quite to the contrary, they fight for every mouthful, and if they can get away with it, they will literally steal a bite from the beak of one of the other members of the flock. The most abundant fish in these waters, at least at this time of year, is the gara, or log sucker. The scales of this fish have gradually evolved into hard plates, while the gara's pectoral fins end in a thick, sharp spine. These fins can be fixed in an extended position and driven into the esophagus of a predator to asphyxiate it. But cormorants, having choked on these fish plenty of times, have learned how to place them in a specific position so that they can swallow them without suffocating to death. It looks like they're playing with their food, but it's no game. It's a very specialized technique to tire out and make their prey dizzy, as they try to break the fish's defense of dangerous, sharp fins. Cormorants have developed this strange behavior only in the swamps of Brazil and nowhere else, and they don't use this technique with any other type of fish. It allows them to eat what no other water bird in this habitat can. The only weak spot where they can kill these fish is the eye socket. And once it's dead, a gara isn't the least bit dangerous, although cormorants often swallow them alive. Many animals' diets depend on the climate, specifically on the ripeness of the fruit in the plant kingdom. Of course, plants certainly try to defend themselves from herbivores, but they also try to forge alliances with them on occasion, especially when the time comes to reproduce. That's why plants invented fruits and nuts, which have become an essential element of many animals' diets. Fruit is food in abundance, with no side effects. That's an unbeatable offer. The acorns of Holm oaks are a nutritious dish that allows red deer and many other animals to get ready for winter, which is a period of scarcity. The deer also use their horns to knock down the acorns a few days ahead of the Holm oaks' natural schedule. And that way they can make sure they don't eat any wormy acorns, either. All the species are connected to each other in some way. The large red deer eat the acorns of the Holm oaks. The Holm oaks are pollinated by beetles. And the beetles eat what the red deer leave behind. Everything is made use of and recycled so that the habitat doesn't run out of resources. These little beings are coprophagous. They eat feces. And in the season when the Holm oaks produce their nuts, the deer's waste is more nutritious than ever. And that's why we're seeing these balls. They're not part of a game. They're a future edible crib. The female beetle will bury it and lay an egg on top of it. And next year, a new, well-fed little beetle will emerge from the soil. Eating to survive has to establish the right balance between consumption and production at all levels of the food chain. Eating for life includes the last supper. The big carrion eaters feed on corpses, removing them from the habitat. That's why they are given a fundamental role in the ecology of each environment. But the true wizards that make all the remains of dead plants and animals disappear, the ones in charge of completing the cycle of each piece of the cake, are invisible. Countless microorganisms play a role similar to that of vultures, but more profound. They decompose all the way down to the molecular level everything that was once alive. Bacteria turn organic material back into inorganic material, into minerals that dissolve into the earth so they can feed the plants again, so that everything can start over again. The vultures we do see show us the physical destination that we will all share someday, forming part of the grand banquet, eating and being eaten. Hunger is the engine that drives the world. It guides the planet's inhabitants, all the species, contributing to decide their adaptations. This should also encourage us to share and to save, since a scant few of us are gorging on everyone's planet.