The Surprising Ways Animals Self-Medicate

Going to the doctor or reaching for an over-the-counter drug when you’re feeling sick may seem like uniquely human activities. After all, when’s the last time you saw a pigeon with a bum wing sporting a cast? But as scientists are steadily learning, the basis of medicine—the act of doing something to relieve or prevent illness—extends far past the origins of humanity.

In his upcoming book, Doctors by Nature: How Ants, Apes, and Other Animals Heal Themselves, Emory University biologist Jaap de Roode takes the reader through a breezy and fun exploration into the complex world of animal medication.

The book starts with de Roode’s research on how monarch butterflies protect their young from parasites by laying eggs on milkweed plants with higher levels of a particular toxin. From there, he cites the work of many other scientists to detail how chimpanzees, ants, bees, and even our pet cats can practice their own form of medicine.

Gizmodo spoke to de Roode about his inspiration for the book, why medication among animals is likely even more common than currently believed, and the value of rediscovering lessons about the natural world that our ancestors once readily knew. The following conversation has been lightly edited for grammar and clarity.

Ed Cara, Gizmodo: What exactly compelled you to write a book about animal medication and to branch out in covering so many other animals besides the monarch butterfly?

Jaap de Roode: It’s just such a cool topic, and I’ve always loved animals. But I met a lot of resistance when I first studied the monarch butterflies and came up with the idea that they can use medication. And that resistance really stemmed from this idea that animals have to be super clever and have super big brains and to be as much as humans can be [to use medicine]. So in some ways, I just wanted to demonstrate that this is not the case. That there are actually so many animals that have these amazing abilities to medicate themselves, their offspring, and their brothers and sisters. That to me was really important—to make people notice. It’s exciting but also so important to realize that for many reasons.

Gizmodo: You provide over a dozen specific examples of animal medication throughout the book. But it also seems like we’ve still just barely scratched the surface of this phenomenon. Do you expect scientists like yourself will end up finding a myriad of other animals that practice medicine?

de Roode: Really, this field scientifically has only been going on since the 1980s, when Mike Hoffman and others began looking at chimpanzees, and now we’re looking at all sorts of insects.

We’re also seeing that people are starting to think about this more now. A lot of the examples that I described in the book really stemmed from serendipity—people weren’t looking for it, but they found it. And so that’s another thing that I hope to do with the book: to show people that there is something real out there and rather than find it accidentally, we should start looking for it purposefully. I’m looking at my bookshelf right now and I see a book about mosquitoes and, you know, there are some ideas that mosquitoes may actually [self-medicate] as adults. It’s only the females that suck blood, and other than that, the males and the females when they’re not breeding, they’re drinking all sorts of nectar. And we know that nectar has all sorts of plant chemicals in them. So even at that level, we may find that mosquitoes do it as well. And that’s just one example. So, yes, I think there will be many, many more.

Gizmodo: A common theme you keep going back to is the idea that today’s scientists are oftentimes rediscovering the lessons that people in the past learned from just observing the animals around them. What are some of the ways that both us and the animals that we share our world with can benefit from learning more about the kinds of animal medication that are happening everywhere?

de Roode: For me, the most surprising thing in writing this book was just discovering how much we used to know and how we then got rid of those ideas. And it’s especially true for Western society, where we like to believe that humans are not part of nature and we need to be unique. And so we’re always looking for ways that make us better or cleverer than other species. It’s been this realization that we are just rediscovering things that people had known thousands of years ago.

There are many examples of it, like how traditional healers and shamans have looked at animals to come up with all sorts of medical treatments. And even aspirin probably came from people looking at bears coming out of hibernation using the bark of willow trees. So we can see those benefits for human drug discovery. But I think we can also benefit in other ways and for the animals’ benefit as well.

I talk about these livestock experiments in the book. And I think it’s so fascinating that when you let sheep and goats and cattle assemble their own diets—you provide them with what they need for nutrition, but also give them choices from medicinal plants—that they’re actually really good at meeting their individual needs and also at healing themselves. And that means we don’t have to use antibiotics and anthelmintics as much, which then means we’re not going to create the drug resistance that we’re  really suffering from right now. So you give animals a better life and it’s better for their welfare.

The same is true with honey bees. There’s this ongoing honey bee crisis. And part of the reason we have a crisis is that we believe that bees are stupid, so we do stuff for them instead of letting them medicate themselves. But bringing that back will make the bees healthier, and that will make us healthier. It’ll help with all the pollination, which we need for our food production.

If we make happier animals, it’ll make for happier people.

Gizmodo: Outside of your personal work with monarch butterflies, what’s your favorite kind of animal medication that you’ve learned about in your work for the book?

de Roode: My favorite story is the finches and sparrows that use cigarette butts [to prevent parasitic infestations of their nests]. And it’s partly because I had known about the research before, but going to Mexico and meeting the researchers there, seeing the nests, and seeing the birds, it was so fascinating. But it also really showed how adaptable animals can be and especially these birds that nest in cities and really adapt to them. And it’s kind of opportunistic because if there are no cigarette butts, they will use other things such as nicotine plants or other plants that have chemicals that also work against these parasites. Just seeing how inventive these animals are, it was just such a beautiful story and I really loved it.

Doctors by Nature: How Ants, Apes, and Other Animals Heal Themselves, published by Princeton University Press, will be out on March 4th.