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How Animals Medicate Themselves in the Wild

Animals are happy and healthy by nature. Of course, life has its ups and downs. That’s natural too. So what do animals in the wild do when they fall ill?

For common, minor upsets otherwise healthy, happy animals are perfectly equipped to heal themselves. The wonderfully complex immune system knows what to do to heal. Resources are mobilised from the appropriate cells, tissues and organ systems to support the healing process and, before you know it, health is restored.

For some problems, however, additional support is required to allow full healing. If animals don’t have the resources or nutrients they need to heal within their organs and tissues, they may look for a remedy in their environment.

Zoopharmacognosy is a relatively new field of scientific study that looks at how animals select and use plants from their environment to heal themselves and prevent disease. It’s an exciting new area for interdisciplinary research that involves many fields of study including medicine, ethology, psychology, and botany.

Zoopharmacognosy – from the Greek zoo meaning ‘animal’, pharma meaning ‘drug’, and gnosy meaning ‘knowing’.

Of course, both domestic and wild animals are also known to poison themselves feeding on toxic plants in their environment, so the behavioural strategy is clearly not without its failures. However, because of the potential of self-medication behaviour to greatly enhance the health and wellbeing of animals we care for, it is increasingly a subject of serious study.

Biologists began documenting self-medicating behaviour in wild animals in the 1970’s watching chimpanzees. A researcher observed a chimp being very choosy about the leaves it was eating. Carefully selecting by mouth only certain leaves and swallowing them whole. The leaves were later found in the stools, whole and undigested.

At first the scientists had no idea why they did this, as it didn’t appear to be for nutritional purposes. But with further observation, by studying the behaviour, plants and stools more closely, the researchers found an explanation for the behaviour.

The chimps involved in this behaviour were apparently suffering with intestinal worms. And the leaves they carefully selected were found to be covered in tiny hairs or trichomes. Folded and swallowed whole, the hairy leaves would open up and act as a mechanical scour, helping to dislodge worms as it passed through the intestine and out with the stool.

Self-medication behaviour has since been observed by scientists in a wide variety of wild animals – from insects and birds, to bears and gorillas. We have all seen dogs eating grass, often vomiting it up afterwards. Well, it seems animals everywhere are doing it – using plants not only for food, but to support the healing process and help prevent disease using a broad range of strategies.

Here are further examples of what has been observed:

  • Chimpanzees, Bonobos and Gorillas eating leaves to help with worms
  • Capuchin monkeys rubbing their fur with plants and millipedes to repel insects
  • Brown bears chewing a root, and rubbing the paste on their faces to deter insects
  • Birds rubbing ants on their plumage to deter lice
  • Rats lining their nests with plants to reduce fleas
  • Elephant eating a specific plant before birth
  • Ants incorporating plant resin in their nests to reduce microorganisms
  • Starlings lining their nests with plants to reduce parasite infestation
  • A variety of animals eating soils or clays to aid digestive upsets or nutritional imbalances

Self-medication, as a behavioural strategy, seems to involve both inherited and acquired aspects.  Scientists propose that animals that self-medicate rely on hedonic feedback (‘eating that makes me feel better/worse’) along with individual learning. Illness seems to change an animal’s preference and tolerance for certain plants. For example, plants that are high in tannins or very bitter are often avoided as a food source due to the taste and detrimental effects on digestion.  However, in times of intestinal disease (such as diarrhoea or intestinal parasites), these same plants may be actively sought out for their beneficial effects, with diseased animals adapting their diet to feel better and enhance wellbeing.

Zoopharmagognosy is not just for scientists. The knowledge that animals can learn what they need to be well gives conservation, farming and gardening new meaning. Whether it’s for food, nesting material, parasite control, or medicine, by protecting natural environments and cultivating gardens we can help to provide animals with the plants required to be happy and healthy.

Some ideas to get you started:

  • Learn about herbs and how they can be used safely to nourish and support the wellbeing of animals.
  • Plant indigenous gardens and conserve local flora to allow all the animals, the wild ones too, to supplement their nutritional and health needs.
  • Observe the behaviour of the animals in your care, the big and the small, and let us know what you discover.

Remember that just because herbs are natural does not mean they are safe. Many herbs can be poisonous to animals, even when safe for humans. So always take care. Check with your veterinarian if you are unsure whether a particular herb is safe for your animals.

Photo Credit – Richard Crowley, Creative Commons.

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