Humans sure have it easy. When we fall ill, a quick visit with the doctor and a prescription later does the fine job of making us well. Even pet animals have the luxury of a veterinary doctor, but what hope is there for wild animals when they get sick?
Well, stay your beating heart; they are not completely without hope. A surprising number of wild creatures have figured out ways to use herbs, resins, and even alcohol and nicotine for health’s sake.
First on the list are primates who are particularly good at exploiting the medicinal properties of plants. Chimpanzees, bonobos, and gorillas have all figured out that swallowing rough leaves can purge their intestines of parasites.
Chimps plagued by roundworm infections have been known to eat plants with anti-parasitic properties, despite their bitter flavour and lack of nutritional value.
In the words of Jaap de Roode, assistant professor of biology at Emory University:
These primates seem to know what they are doing. They are not so different from humans. They can learn from each other and they can make associations between taking medicinal plants and feeling better.
But not all animals self-medicate consciously, in some, the behaviour is more innate.
But even insects use substances to keep themselves and their offspring healthy as the following examples show:
When infected and given the choice, these infected butterflies will lay their eggs on anti-parasitic milkweed, thus protecting their offspring from infection. But healthy butterflies don’t display this preference.
It may not be a conscious choice by these butterflies, but it is a choice nonetheless, says Professor de Roode.
Woolly Bear Caterpillar
Insects like the woolly bear caterpillar employ strategies to avoid and treat infection. They ingest plants that are toxic to parasites.
They incorporate antimicrobial resin into their nests.
Image credit: Jared Belson
These lay eggs in alcohol from fermented fruit to protect their little ones from parasitic wasps.
House Sparrows and Finches
Even birds have a few medicinal tricks up their sleeves too. In cities, house sparrows and finches have been known to add cigarette butts to their nests, which can help to reduce mite infestations because nicotine is an effective bug repellent.
Understanding how animals defend themselves against parasites can affect how scientists model diseases in wildlife populations, and can also affect human food production.
For example, some bees stay healthy by covering their hives in antimicrobial tree resin. But beekeepers tend to weed out these messier, resin-collecting bees, potentially decreasing the overall health of the hive.
Not to be overlooked is the fact that understanding how animals medicate themselves could also help humans better manage health delivery by actually opening our eyes to finding drugs that we could potentially use, completes Professor de Roode.