Even some animals know how to treat disorders naturally
Although I kept pigeons as a boy and with my grandfather attended the annual poultry show during which all sorts of breeds of chicken and other domestic fowl were exhibited, I’ve never been much of a birdwatcher. However, what did catch my attention during some of our walks in the forest were birds that were seemingly taking a ‘bath’ in ant nests.
I later learned that many birds pestered by ectoparasites like featherlice and mites deliberated exposed themselves to ants so that the latter might attack some of the vermin in the bird’s plumage directly or by secreting formic acid as a repellent. These birds that were using ants to treat themselves remind me of some fish that ‘visit’ cleaner fish to help them in their attempt to get rid of parasites on their skin.
However, it’s not just birds and fish that know how to fight disorders ‘naturally’. For hedgehogs, it’s been known for a long time that they anoint themselves with frothy saliva applied to their spines after having licked or chewed toad skin or some other smelly or mildly poisonous substance. Since these insectivores cannot scratch themselves easily and often harbour masses of irritating ectoparasites between their spines, self-anointing is their method of choice to approach the nuisance. Rubbing their furs with millipedes, in other words arthropods that produce benzoquinones and cyanide-like defence substances when attacked, has been reported from a variety of monkeys, but that even unwellness, stomach upsets and intestinal worms are treated by apes through self-medicative behaviours has been explored by the remarkable scientist Michael Huffman, a Professor of Kyoto University’s Primate Research Centre, with whom I corresponded while living in Japan.
Prof. Huffman, who has made the study of self-medication in animals his main research area, discovered that obviously sick chimpanzees, evidenced by weight loss, diarrhoea, lethargy and worm infections would decide to chew the bitter pith of a plant known as Vernonia amygdalina. That particular plant never features as a regular or appreciated food plant but is only sought after when an ape feels sick. Huffman’s research showed that recovery from the symptoms of ill health was noticeable in two chimps as early as 20-24 hours after the ingestion of the bitter pith of the therapeutic plant. A drop in the number of eggs from the intestinal worm Oesophagotsomum stephanostomum in the apes’ faeces from 130 to 15 within 20 hours post-self-treatment provided further evidence of the efficiency of this form of self-medication.
A biochemical analysis of plants like V. amygdalina revealed the presence of bioactive compounds with antihelmintic, antiamoebic, antitumorous, antischistosomiasis and antibiotic properties. However, not only the bitter pith of V. amygdalina was used therapeutically by chimps, they sometimes accept poisonous and indigestible leaves from 34 different plant species in an attempt to ‘mop up’ free-living worms and possibly to alleviate abdominal pain. Unusual behaviour in animals is frequently associated with an individual’s unwellness, but when such animals seek out certain foodstuffs that they would normally avoid, self-medication may be involved. However, it is often not recognized correctly, when actually it is not even terribly rare. Cats nibbling and swallowing grass blades to induce vomiting, female elephants known to eat certain leaves of borage species during labour, dogs swallowing clay to stave off fatigue, all such behaviours are designed to make the animal feel better and are thus by definition self-medicative behaviours. Have humans perhaps sometimes learned their therapies from animals? Prof. Huffman thinks so and backs up his view with a report of a Tanzanian medicine man who discovered an important anti-dysentery treatment by observing a sick porcupine eating the roots of a plant known locally as mulengelele and recovering. And – who knows- the suspected self-medicating Neanderthals might also have got their idea from watching the behaviour of sick animals.
© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2019.
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