RENEE MONTAGNE, HOST:
When cardiologist Barbara Natterson-Horowitz was asked by the Los Angeles Zoo to treat an exotic, little monkey in heart failure, she learned that monkeys can suffer heart attacks from extreme stress - exactly like humans. Dr. Natterson-Horowitz realized she'd never thought to look beyond her own species for insights into human disease - which led to a collaboration with science journalist Kathryn Bowers, and years of research that turned up depressed gorillas, fainting fish, and grasshoppers who binge on sugar when frightened by a spider.
Their new book is called "Zoobiquity: What Animals Can Teach Us about Health, and the Science of Healing."
DR. BARBARA NATTERSON-HOROWITZ: I started out very skeptically, as a cardiologist. I just assumed that many of our diseases were uniquely human. But the overlap was extreme. I mean, a cocker spaniel gets breast cancer, a Siamese cat gets heart failure, a killer whale has Hodgkin's lymphoma. I mean, it really went on and on. And as a physician, what was so intriguing about this - and continues to be - is how little human medicine knows about animal disease, and how utterly relevant that is to human disease.
MONTAGNE: Let's talk about some of the physical illnesses that you came across. Now, everyone knows dogs and cats can become obese. But one of the things the two of you found that may offer a lesson for human health, was the case of the obese dragonflies. Kathryn Bowers, tell us about that.
KATHRYN BOWERS: Yes. Well, we spoke with an entomologist at Penn State University who is a dragonfly expert. And he calls dragonflies the jet fighters of the insect world. They're lean. They're quick. They're nimble. And he was out by his ponds one time, looking at all these different dragonflies, and he noticed that some of them were a little more sluggish than usual. So we took them back to the lab, and he noticed that their wings weren't working quite right. They were collecting fat around their abdomens. And he realized that they had what might be similar to - like a pre-diabetic state.
And they were infected with a certain kind of parasite that was changing the way they metabolize their blood sugar. So that could have implications for how we look at human obesity.
NATTERSON-HOROWITZ: Right. I definitely had always assumed that it was exclusively diet and exercise that determined my patients' body weight. But we learned that in some animals - for example, in these dragonflies - yes, an infection seems to have been driving the dragonflies' obesity; which is not to say that, you know, infection is causing obesity in human patients. But it opens up the door to expanding our perspective on things that might be contributing.
MONTAGNE: There are many things in this book that are surprising that they are not exclusive to humans. And one of them is drug addiction. Kathryn Bowers, read us a passage in the book.
BOWERS: (Reading) In Tasmania, a leading producer of medical opium, users sometimes sneak into the fields. Ignoring security cameras, they hop fences and gorge on poppy straw and sap. Dosed on the drug, they flail around in circles, damaging crops. Sometimes they pass out in the fields, and have to be carried away in the morning. And there's no way to prosecute these trespassing scofflaws, no rehab to send them to; because these freeloading opium eaters are wallabies.
MONTAGNE: Now, wallabies are a kind of kangaroo.
BOWERS: Yeah, like a mini kangaroo.
MONTAGNE: Of course, it's a funny image. But what do these stoned wallabies - what do they have to teach doctors about human addiction?
NATTERSON-HOROWITZ: The fact that animals can sometimes seek substances, presumably to change their sensory state, has a lot of implications, I think, for human beings who have substance abuse problems, and even addiction. One of the things we learned is that in some of the animal populations that do seek substances - whether it's the wallabies; or the bighorn sheep, who seek out lichens, which are hallucinogenic to them - some of the animals seek the drugs, and once is enough. And others go back recurrently.
So there's this - what scientists call heterogeneity in desire and craving, let's say, and seeking of the substances. So that alone, I think, has meaning for human populations. Because it can be puzzling to people - for example - who don't have problems with substances, why someone else does. But seeing that wild animal populations demonstrate differences within the group between individuals of who has that proclivity, I think, has meaning not only for scientists - in terms of looking at that problem - but also to help sort of pull away some of the shame component that burdens people who are dealing with this very difficult disease of substance abuse.
MONTAGNE: There are behaviors in the book - and I'll put this one to you, Kathryn Bowers; you know, as a science writer - that the behavior seems counter-evolutionary; for instance, an affliction associated with human adolescence that's known as cutting or self-mutilation.
BOWERS: When animals are under stress, they will often try to make themselves feel better. And one way that animals do this is by grooming. Sometimes, veterinarians see that animals actually over-groom in situations where they're stressed out. Cats will lick their paws compulsively; dogs might chew the base of their tail, or spin around in circles. Also, veterinarians have seen horses who bite their flanks.
MONTAGNE: And Dr. Natterson-Horwitz, the horses biting their flanks - why are they doing that?
NATTERSON-HOROWITZ: So before I actually became a cardiologist, I did a residency in psychiatry. And I spent time with some human patients who are cutters. It can be very hard to understand why they're doing it. And yet they tell us that it provides them with relief, which seemed counterintuitive to me.
But thinking about it more, and looking at what animals do when they're self-injuring, you see that they're over-grooming in an attempt to tap into the neuro-circuitry that provides comfort and relief with grooming - and dialing it up. Veterinarians know that stress, isolation and boredom will fairly reliably lead to self-harm in certain animals that are susceptible.
Knowing this, they can take steps to prevent stress, isolation and boredom in their animals. And when an animal does exhibit those behaviors, they have a very specific behavioral agenda to help them. And this is information that I actually think would be really helpful on the human side, and caused me to even wonder whether it'd be interesting to have psychiatry residents spend time with animal behaviorists.
MONTAGNE: Well, just finally, what does it all add up to, for you?
NATTERSON-HOROWITZ: So animals and humans get the same diseases. But veterinarians and physicians rarely collaborate and communicate. And this is a loss, because there is a tremendous amount of opportunity to develop a broader perspective about disease. In my own practice as a cardiologist, going to the zoo and working with veterinarians has made me a much better doctor.
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MONTAGNE: Dr. Barbara Natterson-Horowitz and Kathryn Bowers. Their new book is called "Zoobiquity: What Animals Can Teach Us about Health and the Science of Healing."
This is MORNING EDITION from NPR News. I'm Renee Montagne.
DAVID GREENE, HOST:
And I'm David Greene.