Forest animals heal themselvesFrom ants and bees to deer and wolves, animals use plants to heal themselves. They know how much to eat of "poisonous" plants to get healthy. And they can match cause and effect, even if the two are more than a day apart. Scientists puzzle over whether the knowledge of healing herbs is innate or learned.
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Wild animals suffer not only from parasites in their fur and on their skin. viruses, bacteria, worms, protozoa infect them, colonize lungs, intestines, spleen, brain. Our animal relatives suffer from any number of diseases, which especially young and weakened animals ravage away. On average, two-thirds of the offspring of wild animals die in their first year, and disease is a major contributing factor. So it's no wonder that animals have learned to help themselves over the course of evolution. From bees, ants, butterflies, chimpanzees, sparrows and sheep, scientists now know how they help themselves against diseases. "I believe that every animal species self-medicates," says Michael Huffman of the University of Tokyo. He was the first biologist, who in the 20. century described the self-selected medicinal plants in chimpanzees. Now considered one of the leading researchers in the field of wildlife self-medication.
Animal helpers: birds, by the way, also use other animals to arm themselves against mites. 200 species of birds are known to sit in anthills and shower in the formic acid that protects them against insect infestation. Since plants themselves have developed a large arsenal of chemical weapons to protect themselves against predators, insects also use the toxic components to kill their own pests with them.
Obviously there are herbs against the diseases of wild animals. Wild animals know the herbs they need to roll in to ward off parasites in their fur. And they know which leaves, stalks or roots to eat for infections, certain worms or stomach upsets. Dog owners know the behavior: Dogs selectively choose certain types of grasses in a meadow and gobble them down whole.
Grass for the stomach
A short time later, the dogs vomit up the grass or excrete the stalks again undigested. Obviously the dogs know what kind of grass they need to feel better. Undigested blades of grass are also found in the piles of foxes, wolves, and coyotes, and it stands to reason that wild canines have the same knowledge as their domesticated relatives about natural medicinal herbs.
Wallowing, rolling, bathing against critters in the fur
Bathing helps against bugs in the fur. Hares roll in the sand, wild boars wallow in the mud, red deer leave their wallows in summer only to graze. For hours they lie in forest pools and protect themselves from mosquitoes and ticks in the cool water. They are real pests in summer. Deer and roe deer therefore like to retreat to airy heights during the day, so that the mosquitoes are driven away by the wind. The summer has for deer. Deer not only advantages. Even if the food supply is good and the leaves provide sufficient protection from glances, ticks and mites are real pests. Over the millennia, however, animals have developed strategies for driving the little arachnids out of their fur: bathing.
Ticks loiter in grass and low vegetation, especially like to camp at the edges of meadows to the forest. For humans, dogs and some other domesticated mammals, ticks can be dangerous. When sucking blood, the larvae and nymphs of the common wood tick Ixodes ricinus transmit Borrelia bacteria and can cause Lyme disease in humans. Wild animals such as red deer, fallow deer, roe deer or fox sometimes have Borrelia bacteria in their blood, but do not develop the typical Lyme disease symptoms such as fever, reddening of the skin or paralysis in the legs. They seem to be immune. Also, deer, deer and other ruminants are obviously unsuitable as hosts for the Borrelia bacteria. They do not pass the borrelia bacteria to other ticks.
Deer also protect humans from Lyme disease
Mice transfer Lyme disease to young ticks in the larval and nymphal stages. In a mouse species, U.S. scientists have detected Lyme disease symptoms such as loss of coordination and numb hind legs. And here it comes: American and German scientists ame that in small areas there is a connection between the amount of deer, ticks and Lyme disease. The more deer or. in the U.S. white-tailed deer there are in an area, the fewer ticks can become infected with Lyme disease. In Germany, that would mean deer and elk would reduce the number of ticks infected with Lyme disease – and wildlife would thus protect humans from Lyme disease as well.
So far, the native animals in Germany's forests have not been among the preferred research objects of scientists. Self-medication in animals has hardly been studied so far, but scientists have observed and analyzed it in some animal species. Our closest relatives, the chimpanzees, have excelled, because they are so well studied that they can hardly do anything that scientists don't notice.
Chimpanzee knows drug cocktail
Still, it took decades for primatologist Michael Huffman to accidentally notice the strange behavior of the female chimpanzee Chausiku in a forest in Tanzania. Huffman noticed that Chausiku built a nest in a tree, laid down in it and snoozed there all day long. Meanwhile, her cub was gyrating around in the tree unsupervised, something chimpanzee mothers wouldn't usually allow. At the end of the day, Chausiku got up, slowly climbed down and looked for a shrub. She chewed the leaves, swallowed the juice and spit the rest back out.
Huffman asked a local companion from the Tongwe what kind of shrub it is. The shrub is poisonous, said the man from the Tongwe, his people use the leaves as medicine against stomach aches and parasites. Biologists found that the shrub Vernonia amygdalina has twelve different ingredients against parasites. So Chausiku had eaten a whole cocktail of drugs. And just as much as was good for her and did not kill her. She did not know only what to take to heal herself. But also how many of the leaves are helping her. Huffmann henceforth paid attention to when the chimpanzees ate the leaves of Vernonia amygdalina and examined their feces. On such days, he found up to 90 percent more worm eggs in the piles.
Since plants have developed mechanisms to protect themselves against predators, insects also use the toxic components to kill their own pests. The caterpillars of the bear moth (but not pictured here) eat leaves of plants that contain toxic alkaloids when attacked by parasitic flies. The caterpillars thus increase their survival rate by ingesting just the right amount of alkaloids and killing the flies with the plant toxin.
Cigarette butts against bird mites
Montserrat Suarez RodrIguez of Mexico City University observed that house sparrows and bullfinches on campus collected cigarette butts and brought them to their nests. People in Mexico have been using the parasite-repelling effects of tobacco for thousands of years. Tobacco leaves and decoctions in the house help against ants and parasites. But should the sparrows know this too? Suarez RodrIguez and her colleagues then examined the nests, set up thermal cameras and discovered: There were fewer mites in the nests with cigarette butts than in the other nests.
Birds, by the way, also use other animals to protect themselves against mites. From 200 bird species also in Germany it is known that they sit down in anthills and shower in the formic acid that protects them. Since plants themselves have developed a large arsenal of chemical weapons to protect themselves against predators, insects also use the toxic ingredients to kill their own pests. The caterpillars of the bear moth eat leaves of plants that contain toxic alkaloids when attacked by parasitic flies. Caterpillars increase their survival rate by ingesting just the right amount of alkaloids and killing flies with the plant toxin.
Most knowledge must be innate, because how would the caterpillar know which leaf to eat? Some medicine skills animals acquire over the course of their lives, and they peek at behavior. But how does the chimpanzee cub know that the leaves of a particular shrub have cured its mother if the effect doesn't kick in until a day after eating it? Huffman now teaches at the University of Tokyo. Specialized in self-medication of animals. He ames that people in earlier times also learned from the animals. You have observed them. Then even the leaves or roots tried. So the forest and its inhabitants were already medical teachers for people thousands of years ago.