NEW TERRITORIES For generations, animals have self-medicated and looked towards nature to rid them of their problems. Does this mean we can do the same, questions TS Channesh
You must have observed dogs and cats eating grass. Ever wondered why? Well, that’s probably because they have an upset stomach. Eating the grass induces vomit and gives some relief. Some lizards are believed to counteract a venomous snake bite by eating a certain root. Baboons in Ethiopia eat the leaves of a certain plant to combat the flatworms that cause schistosomiasis.
Incidentally, several studies have documented survival strategies like these in birds, bees, lizards, elephants and chimps. Yes, a wide range of animals self-medicate. Animals, all over the world, eat certain things to make them feel better or prevent a disease or aid their digestion. Even creatures with brains the size of pinhead, have somehow stumbled upon this ingenious strategy. But till today, it isn’t clear if animals know the logic behind this weird ritual. But many of them seem to have imbibed an innate ability to detect the therapeutic constituents in plants. Even though the evidence is circumstantial, examples are aplenty.
Examples aplenty
Animals, it seems, have found their own pharmacy, right in their neighbourhood. Did you know that red and green macaws eat clay to aid their digestion and kill harmful bacteria? Female wooly spider monkeys in Brazil add plants to their plate to regulate their fertility. Pregnant lemurs in Madagascar nibble on the leaves and bark of tamarind and fig to induce milk production, kill parasites and increase the chances of a successful birth. What more, certain leaves are eaten by pregnant
elephants to induce labour!
However, a major number of studies of animal self-medication happens in great apes. A Japanese anthropologist, Toshisada Nishida, observed chimpanzees eating aspella leaves in Tanzania. Since the leaves had no nutritional value, Toshisada was intrigued by this particular ritual. Harvard primatologist, Richard Wrangham observed the same behaviour amongst the apes at Jane Goodall’s Gombe Reserve. The animals weren’t getting any nutrition, so why chew on them?
It was then that a biologist Michael Huffman suggested the self-medication concept. Michael, who worked at Primate Research Institute at Kyoto University, first saw a parasite-ridden, constipated
chimpanzee chew on the leaves of a noxious plant – a plant it would otherwise avoid. The next day, the chimp had recovered completely. It was later discovered that the bristly leaves and stem of the plant helped scour the intestines of the chimp and killed parasites. Even the chimps in Africa followed the same self-medication methodologies.
Michael then established a widely-used criterion for judging when an animal is self-medicating. First, the plant eaten cannot be a regular part of the animal’s diet. Second, the plant must provide little or no nutritional value to the animal. Third, the plant must have been consumed during those times of the year when infections are common. For instance, during monsoons, when parasites breed in plenty. Last but not the least, the plant must be consumed only by a said few in the group. If all these standards are met, then it is safe to assume that the animals are self-medicating. Researchers have identified around 40 plants that help the animals in this process.
Several observations point to the fact that self-medication practice can be either innate or behavioural or both. Evolution also plays a part in this procedure. Apes, being evolved more than other species, pick up on this practice from their elders and pass it on to their progeny. This
practice isn’t just about instinctive behaviour. Animals seem to know the natural solutions to their problems and even apply them in their daily lives. For instance, the monarch butterfly lays its eggs on milkweed, which has anti-parasite properties.
This particular field is so widespread now that it even has got a name of its own – Zoopharmacognosy. Scientists working in this field, are convinced that the future of pharmacy lies here. By observing these intelligent animals, human beings can find new and effective drugs. Why, much of our ancient and folk medicine came from medicine men watching animals self-
medicate. It’s time we looked towards nature for a better world.
(The author is dean, GPS Institute of Agricultural Management.)
