National Public Radio (NPR) recently ran a story on “What Animals Can Teach Humans About Healing” (June 12, 2012; http://www.npr.org/2012/06/12/154523594/what-animals-can-teach-humans-about-healing). Featured in the story was the recent work of Dr. Barbara Natterson-Horowitz and her co-author, Kathryn Bowers (“Zoobiquity: What Animals Can Teach Us About Health and the Science of Healing”). Their book explores the parallels between humans and animals and what nature can teach us about the human mind and body; it documents case studies about animal and human commonalities to explain new developments in health care. In the book, the authors write about diseases and afflictions of animals, both domesticated and those living in their natural habitat, which we erroneously assumed were purely of the human condition. Diseases and conditions such as obesity and diabetes… a dragonfly with abdominal obesity and high blood sugar…and, really difficult mental health conditions such as addiction and self-harm behaviors…wallabies that get stoned on opium, bighorn sheep that forage for hallucinogenic lichens, and horses that bite at their own flanks and dogs and cats that chew their own paws! And, just like in humans, there is a range of these behaviors in the animal world…almost all wallabies and sheep try out the hallucinogens in their environment, but some never come back again to partake and others return over and over again as if they are truly “addicted”.

Of course, I gravitated to the chapter on eating disorders. I was struck by accounts of grasshoppers that binge on sugar, beluga whales and gorillas that regurgitate and reingest their food, and the myriad examples of lovable critters that purposefully restrict their food intake. One real eye-opener came from reading about food restrictors in the animal world that actually forego their normal diet in favor of “negative” calorie fillers like straw, much like the many humans with anorexia who consume large quantities of lettuce and celery instead of more energy- and nutrient-rich foods. And, then there are the moles and beavers and screech owls and many more species that horde food in overabundance.

So, why do these animals engage in these behaviors that we typically think of as uniquely human? The not-so-simple answer appears to be stress. Grasshoppers binge on sugar only when frightened by a spider – sugar gives them quick fuel for escape; whales and gorillas regurgitate and reingest in captivity but not in the wild – this ‘routine’ seems to bring them solace. Animals restrict and horde for self-preservation and “anxiety reduction”…they restrict when they perceive a predator in their environment, and they horde as a means for reducing their exposure to risky, high-predation situations and for protecting them from possible future food shortages. Interestingly, in some cases the stressor isn’t the predatory environment but rather the social environment of the pack, or herd, or flock. Adolescent gorillas mimic the regurgitation behavior they observe in their elders, and the cycle perpetuates.

I’m looking forward to reading the other chapters in the book which, by the way, have some pretty catchy titles (“Roar-gasm”, “Grooming Gone Wild”, “Zoophoria”, and “Fat Planet”, to name a few). In the meantime I’ll be pondering these questions. Is anorexia “fear of feeding as a protective physiology gone astray”? Is bulimia a melding of stress-induced rumination with self-soothing through prolonged feeding pleasure? Is binge eating disorder an overactive coping response geared to provide simple sugars for quick energy needed to flee a stressful situation? How can considering the evolutionary origins of eating disorders help us educate, communicate with, and treat our patients?

By: Dr. Kim Brownley