Plants know when to stop eating

Forest animals heal themselves

The native animals in Germany's forests have not yet been the preferred research object of scientists. Animal self-medication has hardly been studied, but scientists have observed and analyzed it in some animal species. Our closest relatives, the chimpanzees, excelled because they are so well studied that they can hardly do anything that scientists fail to notice.

Chimpanzee knows drug cocktail

Nevertheless, it took decades before the primate researcher Michael Huffman accidentally noticed the strange behavior of the female chimpanzee Chausiku in a forest in Tanzania. Huffman noticed that Chausiku made a nest in a tree, lay down in it, and dozed there all day. In the meantime, her cub was doing exercises in the tree unsupervised, which chimpanzee mothers would normally not allow. At the end of the day Chausiku got up, slowly climbed down, and looked for a bush. She chewed the leaves, swallowed the juice, and spat out the rest.

Huffman asked a local Tongwe guide what kind of shrub it was. The shrub is poisonous, said the Tongwe man, and his people use the leaves as medicine for stomach pain and parasites. Biologists found that the shrub Vernonia amygdalina has twelve different ingredients against parasites. So Chausiku had eaten a whole cocktail of drugs. Just as much as she got and didn't kill her. She didn't just know what to take to heal herself. But also how many of the leaves help her. From then on, Huffmann paid attention to when the chimpanzees removed the leaves from Vernonia amygdalina ate and examined their feces. On such days he found up to 90 percent more worm eggs in the pile.