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Zoo pharmacognosy



Have you ever seen dogs eat grass and wonder why they do it, particularly as it usually makes them sick? Well, if you observe them more closely you will notice that they prefer a particular type of broadleaf grass called couch grass or, as it is also known, dog grass.

The reason why they do it may well be to detox themselves as couch grass has well-known liver and kidney detoxification properties and aids with digestion. Dogs, it would appear, are innately aware of this and eat it to cleanse their systems. What these dogs are doing is called zoo  pharmacognosy.


It seems like a bizarre idea but, of course, it is perfectly logical. Animals have survived for millions of years without the need for human intervention. It would be extreme arrogance to assume that, without the use of modern veterinary medicines, animals all over the planet would be dying of multifarious illnesses. In fact, most veterinary pharmaceuticals have adverse side effects associated with them so if a natural alternative is available that particular animal species have utilised successfully studied  for thousands of years, who are we to say that modern treatment is best.  


Studies of animals in the wild have produced evidence that certain species do indeed self-medicate. 

Chimpanzees with digestive problems are frequently observed to eat the leaves of the aspilia plant. These leaves were analysed at the University of California.  They were found to contain high concentrations of a natural antibiotic called thiarubrine-A. They also contained a potent antifungal and anti-parasitic agent, which was used successfully as an anti-wormer. The compound also had antiviral and antibacterial properties. The chimpanzees swallow these leaves whole, unlike other plant leaves which they chew, and they ingest them mostly in the rainy season when the parasites are more frequent. They also chew the leaves of Vernonia amyddalina which has known antiparasitic qualities and again, they only do this sparingly, not on a regular basis. Parasitic infection has been shown to be reduced after ingesting them.


Panamanian white-nosed coatis use the resin from the bark of trattinnickia aspera plant to rub in their fur. This resin has chemicals called triterpenes which have proven antimicrobial and and antiparasitic properties.


North American brown bears chew the root of Ligusticum porteri and smear it on their faces. Ligusticum porteri contains coumarins- organic compounds that repel insects when applied topically.


It is not just plant substances that are used by animals, clay is another naturtal medication that is often utilised. The clay is ingested to alleviate gastrointestinal problems because it absorbs toxins and bacteria. Again, this makes perfect sense as humans have used kaolin and bentonite clay for the same pruposes. It is also thought that clay-like soils can rebalance the PH level in the gut and, as bacteria tend to favour acidic conditions, this can reduce intestinal problems.    

Birds too appear to be aware of the medical benefits of some plants. The European starlings line their nests with wild carrot which has a substance called B-sitosterol which kills the type of mites that would normally invade their nests. In India, the domestic house sparrow uses neem in its nest which is renowned for its antimicrobial and antiparasitic properties. In fact, 7th heaven have used it to successfully treat mange in cats and dogs as well as various other skin complaints. 


The field of zoo pharmacognosy is becoming very popular amongst parasitologists, ethnobotanists, chemical ecologists, conservationists, physicians and zoologists. Evidently more and more people are beginning to understand that nature can provide remedies for illnesses without the need of synthetic pharmaceuticals and that animals have an innate knowledge of this.

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