Zoobiquity: The Astonishing Connection Between Human and Animal Health
By Barbara Natterson-Horowitz, M.D., and Kathryn Bowers
Vintage Books: New York (paperback)
398 pages
Paperback list: $15.95, Kindle $11.99
Hardback release June 2012
What if your golden retriever has a message for you—not that she wants to be fed or taken for a walk—but a message that could save your life? What if animals in the wild could tell us something that could make existence better for them and us? In Zoobiquity: The Astonishing Connection Between Human and Animal Health, cardiologist Barbara Natterson-Horowitz observes that researchers are breaking down the wall between human and animal pathology and in so doing are finding answers to some of the most vexing diseases and conditions that afflict us.
Zoobiquity is Natterson-Horowitz’s neologism joining the Greek word for animal (zo) with the Latin ubique (everywhere). With the help of writer Kathryn Bowers, the author leads the reader through a groundbreaking shift taking place in the way researchers look at our relationship with the animal world, using personal stories and surveying research dealing with problems such as cancer, heart attacks, obesity, self-injury, fainting, venereal disease, addiction, sexuality, eating disorders, and adolescent rebellion.
There always has been an intuition that humans have much more in common with animals than they might wish to admit. This point of view, however, runs contrary to a religious and philosophical myopia that put humans at the top of a hierarchy that devalues non-human species. This began to change in the 19th century, Natterson-Horowitz said, when Charles Darwin posited that all creatures—human included—belong to the same family tree. The theory of evolution has "unnerved" many Homo sapiens, resulting in such rearguard responses as religious fundamentalism ("My ancestors are not apes!") and blinkered research and clinical practices in the world of animal and human medicine. Zoobiquity takes the reader through mounting data from such scientists as Dian Fossey, Jane Goodall, Edward O. Wilson and Stephen Jay Gould that we share much more in common with our relatives in the animal kingdom than we might allow. For example, DNA studies of primates have shown that humans share 98.6 percent of their genome with chimpanzees. Indeed, it has been discovered that humans share genetic structures with nearly all creatures (including plants and bacteria), "our long-lost relatives." The nature-nurture debate of the 1980s has shifted to the question of how much genes interact with culture and the environment. This shift has produced the burgeoning field of epigenetics, which "considers how infection, toxins, food, other organisms, and even cultural practices turn genes on and off to alter an animal’s development," writes the author.
Natterson-Horowitz introduces the section on fainting by telling the story of her 12-year-old daughter passing out before getting her ears pierced. Most of us, she points out, have experienced fainting spells—from getting up too fast to blanching at the sight of our (or another’s) blood. Fainting occurs in the animal world frequently and has serious consequences. Researchers have found that fainting in animals seems to coincide with brachycardia, the slowing of the heartbeat. Animals have evolved with a shift in the parasympathetic part of their nervous systems when faced with a threatening situation. Feigning death can be an effective response to a predator. This phenomenon of "alarm brachycardia" means the old "fight or flight" response should be amended to "fight, flight or faint," the author argues. She narrates events in which animals’ hearts slow down so significantly that they appear dead—rabbits, monkeys, fish ... and concentration camp survivors who fainted during mass killings and woke up in the company of dead fellow prisoners. During the build up to the Gulf War, when Iraq aimed Scud missiles at civilian targets in Israel, three fetuses in a Tel Aviv hospital showed signs of alarm brachycardia. When sirens announced an imminent threat of a missile attack, the heart rates of the fetuses, whose mothers were in labor, fell by one half. Of course the occurrence of symptoms in three fetuses does not prove a hypothesis; nevertheless, it is an anecdote that begs for more study.
In the 1990s Japanese cardiologists uncovered physical evidence that stresses such as grief, fear and agony can alter the chemistry and physiology of the healthiest human heart. They termed the phenomenon "broken heart syndrome" and traced its cause to stress hormones. While chemicals like adrenaline can assist in becoming alert to frightful situations, such hormones can also poison heart cells. Natterson-Horowitz found in discussing "broken heart syndrome" with a wildlife veterinarian that there is a similar malady in the animal world called capture myopathy. The vet explained that when an animal is captured—a bird for example—sometimes it dies of no apparent cause. The same stress-inducing chemicals can cause heart attacks in humans can also cause the sudden demise of parakeets, giraffes and rabbits.
One example of how the zoobiquity dialogue is changing how researchers are confronting serious illness in animals and humans is a longitudinal study, the Canine Lifetime Health Project. Begun in 2012, the study is focusing on 3,000 golden retrievers, whose population is high-risk for developing cancer. The pets have every aspect of their environment monitored—from diet to household toxins. The genes of each animal are analyzed and compared. Natterson-Horowitz notes that the study, which will take years to complete, is the kind of research that not only will shed light on the causes of canine cancer—because cancer in dogs often behaves similarly to the disease in human, it may help oncologists find out why humans develop cancer and what can be done to control the disease.
Another instance of "comparative oncology" is found in the study of breast cancer. One of the top killers of women, breast cancer, also strikes a variety of animals, including jaguars, whales and ferrets. One type of breast cancer afflicts people who have a mutation of the gene BRCA1, which also occurs in English springer spaniels as well as other animals. The fact that oncological and veterinary researchers are comparing notes in their search for the causes of breast cancer should be welcome news to women (and men) who carry the mutation in their genes.
As hope-inducing as results may be, you might ask, "Where are the results?" The author cites a study at Memorial Sloan-Kettering that has successfully used human DNA to control melanoma, a deadly cancer in dogs. Because the disease is for all practical purposes the same in canine and human sufferers, researchers hoped the novel treatment would trick the dogs’ immune system into attacking its cancer cells. And it did, resulting in tumor shrinkage and improved survival rates. Now the researchers are working on a similar treatment in humans.
Natterson-Horowitz spends a good deal of the book focusing on the fascinating connections between animal and human sexual health. Her whirlwind review of creature sex going back a half billion years is as humorous as it is informative. Some of her stories would make Borat blush. Remember Elvis’s trademark sexy sneer? She argues that the King had nothing over randy stallions, which also raise a sneering lip to catch the arousing odor of a mare in heat. Erectile dysfunction? Yep, animals get that. Whether it is an affliction of humans or horses, ED has to do with restricted blood flow. In order for one’s Johnson to come to attention, a male horse or human first must relax. But relaxation cannot happen when there is an imminent fear of predators. Though a lurking cougar is not a problem for most men, stress and anxiety (as well as clogged arteries) can cause the mammalian brain to lock up the erection process, resulting in embarrassment, frustration and all the other horrors Viagra commercials have brought to our attention.
Is reductionistic thinking going on here? Hmmm. The author likens the swayback presentation of female animals’ hindquarters in heat (called lordosis) to Betty Grable posing arch-backed in heels in World War II-era pinups. Remember the old saying, "When you’re a hammer, everything looks like a nail?"
After tackling sex, Zoobiquity moves on to drugs. Why is addiction so prevalent in our society? Natterson-Horowitz contends animals have been getting high for millions of years—as a survival adaptation. While it may be a surprise that animals have had opioid receptors for at least 450 million years, it may be even more of a surprise that this adaptation has been a good thing. Foraging, for example, has been found to release dopamine in animals—their brains essentially sending chemical treats to encourage life-sustaining behaviors. Nesting, socializing and breast feeding are among many behaviors that have been shown to be triggers to changing brain chemistry. Humans, as we all know, have their own versions of dopamine and opiate inducers—gambling, shopping, and overworking, not to mention using alcohol and drugs. The author points out that animals tend to face inevitable limits to many of their pleasure-seeking behaviors. Poppies that opiate-loving Tasmanian wallabies consume are available only when the flowers have gone to seed. But humans, equipped with a scheming prefrontal brain, find ways to make the objects of their pleasure available whenever they want them—well, as long as their money, sanity and health hold out. Humans, Natterson-Horowitz says, do well to remember that engaging in the hard work of getting natural feel-good rewards—like exercise, socializing and other life-sustaining behaviors—is the best way to exploit the brain’s pleasure chemistry.
Hard work is the answer to the American obesity epidemic, too, the author argues. Seventy percent of humans in the United States are overweight or obese; a quarter to a half of our pets are the same way. Excess consumption of food in the wild also occurs, Natterson-Horowitz reports; however, in nature times of abundance and scarcity mean that a summer’s fat belly will give way to winter hunger. Like animals in the wild, we are also hard-wired to gorge ourselves. The problem for the First World is that we have face an "eternal harvest" of high-fructose, fatty foods and marketing strategies that tell us to eat in order to prosper and feel better. In addition, researchers are discovering that the metabolism of animals is affected by gastrointestinal microbes that send hormonal messages to our brains saying "Keep eating!" even if what we are consuming is making us fat or sick. Studies also show that interrupting the natural circadian rhythms of animals also leads to obesity. Are long work hours under artificial light coinciding with torpor and expanding girth for you? Interdisciplinary studies of animals and humans seem to say so.
Are there corollaries in the animal world for all of the headline-grabbing maladies afflicting the human race? Natterson-Horowitz may not say so, but she appears willing to entertain the possibility. Whether it is adolescent tattooing and self-mutilation (rooted in anxious overgrooming habits found in bird behavior?) or bulimia (similar to regurgitation behaviors in many species) the author wants to know more. She argues that answers will be found in the expanding conversation between veterinary and medical scientists who consider human beings to be part of—not transcending—the natural world.