Why Jaguars and Jews Have Breast Cancer

If Human Doctors Would Take Off Their Blinkers and Learn Animal Medicine, We Might Be as Healthy as Horses

“What do you call a veterinarian who can only take care of one species?”

An M.D.

It’s a longstanding joke that veterinarians make about doctors, said UCLA cardiologist Barbara Natterson-Horowitz, at an event co-presented by UCLA at the Petersen Automotive Museum. And it’s a joke with bite. It shouldn’t be news that humans are animals too, but sometimes it seems that way to doctors who treat humans.

Natterson-Horowitz–by collaborating with veterinarians, evolutionary biologists, and even wildlife conservationists–is challenging the divide that has long separated human medicine from animal medicine. She and UCLA writing lecturer Kathryn Bowers, authors of the new book Zoobiquity: What Animals Can Teach Us About the Art and Science of Healing, spoke with Los Angeles Times science writer Eryn Brown about the parallels between human and animal diseases, and how all species stand to gain from recognizing where we overlap.

Natterson-Horowitz first became interested in the connections between animal and human health when she was called in to do ultrasounds for animal patients at the Los Angeles Zoo. She began listening to the veterinarians as they spoke during their rounds, and soon noticed more and more animal diseases she’d seen in humans.

“We take our pets to the veterinarian for this problem or that problem,” said Natterson-Horowitz. “It hadn’t dawned on me that there were these parallels. On the one hand it’s obvious,” because we share so much of our genes with chimpanzees, for instance.

Bowers and Natterson-Horowitz investigated which human diseases had animal counterparts. The first big overlap came in cancer, which affects species including llamas, kangaroos, and big cats. We think of breast cancer as a human illness–but, said Bowers, being a mammal means you have breasts, and if you have breasts you can get breast cancer. Jaguars in zoos have a high incidence of breast cancer, which may be related to the BRCA1 gene mutation. (This mutation is often found in Jewish women, and Natterson-Horowitz said that this book chapter had originally been titled “Jews and Jaguars.”) Dairy cows and goats–two animals whose job is primarily to nurse their young–have a low incidence of breast cancer, while studies of humans have shown that women who nurse are at a lower risk for breast cancer.

Are there any diseases, asked Brown, that have turned out to be a dead end in searching for an animal corollary?

The Zoobiquity team’s answer: Epicardial coronary disease is the biggest cause of heart attacks in humans, but because it’s a disease of civilization amplified by our lifestyle and diets, it’s not found in most animals. Animals do have other forms of heart failure, however–including the kind of heart disease that can cause high school athletes to drop dead, which is also found in cats.

The parallels extend to psychiatric diseases. Bowers was surprised to find out that self-injury occurs in animals. “To me that seemed so very, very human, that you would even injure yourself,” she said–it seemed to her to require a sense of self. Yet “animals when they’re under stress will do all sorts of things to make themselves feel better, including turning their own teeth or talons on themselves.”

Horses flank bite or birds peck at themselves until they bleed, said Natterson-Horowitz–compulsive behaviors not dissimilar to OCD in humans. In animals, these behaviors are often related to grooming–as is hand washing in OCD patients.

Animals also have eating disorders. In thin sow syndrome, a pig going through a stressful transition will react by not eating. Some marine animals push on their stomachs to force regurgitation, and then ingest what they’ve just expelled. “It’s a self-soothing phenomenon,” Natterson-Horowitz said.

Many animal species experience adolescence in ways similar to humans: animals transitioning from immaturity to maturity will take greater risks, including approaching predators to inspect them up close.

Natterson-Horowitz and Bowers said that, as they looked for patterns and overlap, they were careful not to anthropomorphize the animals they studied. At the same time, they think researchers have been too cautious in the past about drawing connections between human and animal behaviors. Animals put under stress eat less, limit their diets, and eat at different times than they did previously. Patients with anorexia nervosa do the same thing. “I can’t say it’s connected, but it’s very interesting,” said Natterson-Horowitz.

And when they met with people in the animal world–such as stallion breeders at University of California Davis–a lot of the conversation made animals sound human. Plus, connections can be seen in the genetic patterns humans share with all kinds of species, from primates to algae.

Natterson-Horowitz and Bowers said that, on an everyday level, human doctors can learn from the techniques of veterinarians. Animal doctors must do a lot of their diagnosing through careful, holistic observation instead of relying on patient testimony and machines. Veterinarians, said Bowers, also tend to think about the environment and social structure a patient is embedded in more than human doctors.

In the question-and-answer session, subjects included the connections between plants and humans, animal S.T.D.’s, and depression.

One audience member asked: Will Natterson-Horowitz collaborate with botanists next?

She didn’t say yes or no, but said that plants secrete certain compounds that make them taste bad to predators, similar to the way animals under stress–anxious lobsters, for example–secrete adrenaline that doesn’t make them taste as good.

Bowers was surprised to find that S.T.D.’s occur throughout the animal kingdom–which makes sense when you consider the fact that animals are having unprotected sex with multiple partners. Studying an epidemic of chlamydia among koalas in Australia could prove helpful to us as we look at the koalas who are protected by certain genetic factors.

Do animals ever have depression? Yes, said Natterson-Horowitz. Geese, sea lions, and gorillas are among the animals who have exhibited depressive symptoms.

What’s next for the Zoobiquity team? The two authors said they were looking at bullying in the animal world, and how it resembles the behavior you see in human schoolyards.

Watch full video here.
See more photos here.
Read what veterinarians think human physicians can learn from them here.
Read an excerpt from Zoobiquity: What Animals Can Teach Us About the Health and Science of Healing here.
Buy the Book: Skylight Books, Powell’s, Amazon.

*Photos by Aaron Salcido.

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