The Parasitic Dance of Monarchs and Milkweed

What happens to animals when they get sick? If they’re pets or livestock, we probably call the vet. And the vet may give them drugs or perform a procedure. But what about wild animals? Do they just languish in misery? Well, not so much. It turns out that animals—from bees to butterflies, porcupines to primates—medicate themselves. They seek out bitter plants, they treat wounds, they amputate limbs, they eat clay—the list goes on. This all raises an obvious question: How do they know to do this? How do they know what they know about healing and medicine? It also invites a related question: How do we humans know what we know?

My guests today are Dr. Jaap De Roode and Dr. Michael Huffman. Jaap is a biologist at Emory University, and has studied animal medication in insects; he’s also the author of a forthcoming book about animal medication across the tree of life. Mike is a primatologist at the University of Nagasaki, and made some of the very first observations about animal self-medication in chimpanzees in the 1980s.

Here, Jaap, Mike, and I talk about how they found their way into this field, in both cases kind of by accident. We discuss what defines animal medication generally as well as what defines its more specific subtypes—social medication, allomedication, prophylactic medication, and others. We consider how animals know what they know about healing—whether these medicinal behaviors are mostly driven by innate tendencies, by individual experimentation, by social learning, or by some combination. We talk about the evidence that many of the medical insights that humans have had over the years actually began with observations of animals. Along the way, we touch on medicinal amputation and medicinal cannibalism, geophagy, leaf-folding in primates, animal quackery, bear medicine, why lemurs rub themselves with millipedes, and the anti-parasitic power of cigarette butts.

Alright, friends, this is a fun one. Enjoy!

A transcript of this episode is available here. 

Notes and links

3:00 – A paper describing how birds in Mexico City line their nests with cigarette butts. A follow-up experiment showing that they do so in response to increased presence of parasites.

7:30 – Dr. Huffman’s original study of self-medication by a chimpanzee, using Vernonia amygdalina in Tanzania.

15:00 – Dr. de Roode’s study on “transgenerational medicine” in monarch butterflies.

20:00 – For an overview of animal medication, including definitions and examples of its subtypes, see this recent primer by Dr. de Roode and Dr. Huffman.

25:00 – The recent study on “medicinal amputation” in ants. The recent study on “medicinal cannibalism” in ants.

30:00 –  For an overview of medication in insects, see this recent paper by Dr. de Roode and colleagues.

34:00 – The paper by Mascaro and colleagues showing that chimpanzees treat wounds (to the self and others) by applying insects.

38:00 – A recent review of geophagy—soil eating—in primates by Paula Pebsworth, Dr. Huffman, and colleagues.  

43:00 – A paper by Dr. Huffman and colleagues on chimpanzee leaf-swallowing in the wild. Dr. Huffman later did a series of experimental studies on this behavior, investigating the role of social learning—see here and here.

46:00 – An article on how goats learn to eat what they eat.      

52:00 – An article describing the medicinal properties of Vernonia amygdalina.

54:00 ­– A study showing that lemurs rub each other with millipedes in a possible case of animal medication.

57:00 – A paper by Dr. Huffman in which he describes the use of mulengelele by a sick porcupine. A recent review by Dr. Huffman of what traditional healers have learned from observations of animal medication.

1:01:00 – An article about propolis and its medicinal use in bees; an article about its medicinal potential in humans.  

Recommendations

Doctors by Nature, Jaap de Roode (forthcoming)

Wild Health, Cindy Engel

Nourishment, Fred Provenza

‘Five clever animals that treat and prevent their own illnesses,’ National Geographic

Many Minds is a project of the Diverse Intelligences Summer Institute, which is made possible by a generous grant from the John Templeton Foundation to Indiana University. The show is hosted and produced by Kensy Cooperrider, with help from Assistant Producer Urte Laukaityte and with creative support from DISI Directors Erica Cartmill and Jacob Foster. Our artwork is by Ben Oldroyd. Our transcripts are created by Sarah Dopierala.

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