On a recent morning at the Los Angeles Zoo, head veterinarian Dr. Curtis Eng points out to a visitor a pair of hairy teenage brothers who are two of the zoo’s seven gorilla stars.
“We actually have this bachelor group here," Eng said as he pointed through a glass barrier that separates zoo visitors from the giant apes.
One of the apes makes his way toward the humans staring at him. "That’s Hasani. He’s about two-and-a-half years older than his younger brother."
The zoo primates are treated to top-notch health care, including preventive heart screenings from UCLA cardiologist Barbara Natterson-Horowitz. She's among the physicians calling for more communication between human doctors and veterinarians.
Natterson-Horowitz said a research visit to a zoo forever changed the way she practices medicine.
“We were going to do at the zoo what we do with human patients, which is screen them with an ultrasound of the heart,” she said. "As one of the animals was being sedated, I was making a lot of eye contact because in a human patient that's what you'd do to create trust and connection."
But the veterinarian prepping the primate cautioned Natterson-Horowitz against close-up eye contact with the squirrel-sized Tamarin monkey, telling her that it might trigger “capture myopathy.”
Unfamiliar with the term, Natterson-Horowitz later looked it up. It described an often deadly syndrome in restrained wild animals. But she realized it was almost identical to something researchers had just reported in humans who suffer extreme stress, such as that caused by witnessing the death of a loved one.
“It occurred to me these were probably the same disorders with different names, or they were very connected," said Natterson-Horowitz. "But the piece of it that was just startling was that in veterinary literature and wildlife biology literature, this has been written about for decades, literally decades.”
She said the journal "Nature" had reported it more than 30 years ago.
"So that gulf raised the possibility that there were many other gulfs like that," she said. "And I'm just one cardiologist having this one 'aha' moment and I realized we needed to amplify that."
So Natterson-Horowitz set out to research the wealth of medical information that’s long been hiding in plain sight in the journals of veterinary medicine and wildlife biology. Scientific literature, she said, that few human doctors take the time to read.
"When you know that breast cancer doesn’t just affect human patients, that breast cancer affects big cats like jaguars and tigers and lions and also affects Beluga whales and also affects certain dog breeds, I believe it will improve and expand investigation which could benefit animals and human patients with the same problem.”
Natterson-Horowitz and journalist Kathryn Bowers gathered hundreds of these findings in a book they co-authored called “Zoobiquity." It offers insight into hundreds of human-animal health overlaps that include even harmful psychological behaviors considered uniquely human.
Take anorexia nervosa. Think it's just a problem for teenage girls and young women? Think again: some farm pigs are known to self-starve, said Natterson-Horowitz.
There are documented cases of obesity in dragonflies and bulimia – or self-induced vomiting - in marine mammals. There’s even drug addiction among many species: birds that get buzzed on fermented berries; cows that get high off loco weed; even Tasmanian wallabies that can’t keep their paws out of medical opium fields.
"They’re known to jump over fences and grab the poppies and ingest the poppy sap and the poppy straw until they’re intoxicated," Natterson-Horowitz said. "We learned about big horn sheep attracted to hallucinogenic lichen that grows on the tops of cliffs and they will actually scale cliffs to access this lichen."
It doesn't stop there. Self-injury, also long-believed to be a uniquely human behavior, is shared by some animals. Natterson-Horowitz said veterinarians have long identified and successfully treated it in many of their patients - from caged birds that pluck out all their feathers or peck themselves bloody to stallions that bite serious injuries into their own flanks.
"I think the human psychiatrist, psychotherapists even a parent dealing with the challenging issue of self-injury in a patient child could look to the success that animals experts have in treating self-injury," she said.
And Dr. Eng agrees. "That’s really what our goal is with this whole 'Zoobiquity' thing," he said. "To have the conversation between human physicians and DVMs talking about the various things they have in common and then what they don’t have in common and how to make things better for both sides."