This month, while the patient was lying on a table, a cardiologist made a half-inch incision in the skin of his chest. He removed a small implanted heart monitor with failing batteries and inserted a new one.
The patient, like many elderly men, was diagnosed with heart disease; the monitor will provide continuous data on heart rate and rhythm, alerting his doctors to irregularities.
Closing the incision requires four neat stitches. In a few hours, the patient, a gorilla named Winston, will be reunited with his family at their home at the San Diego Zoo Safari Park.
“Winston, at age 51, is a very old male gorilla,” said Dr. Matt Kinney, a senior veterinarian at the San Diego Zoo Wildlife Alliance led the medical team through the procedure. With improved health care, new technology and better nutrition, “we’re seeing animals live longer, and they’re also healthier for longer,” he said.
In “managed human care” (the term “in captivity” no longer flies in zoos), gorillas can live two decades beyond the 30- to 40-year life span typical in the wild, and longer than zoo gorillas did in past decades.
Like their relatives, however, aging also brings chronic diseases that require examination, diagnosis and treatment. Gorillas are prone to heart disease, the leading cause of death for them and for us.
So now the questions for Winston’s caregivers resemble those facing doctors and elderly human patients: How much treatment? What is the trade-off between longevity and quality of life?
Geriatric animal care has “become more sophisticated,” says Dr. Paul Calle, the chief veterinarian of the Wildlife Conservation Society, based at the Bronx Zoo. “People’s medical and surgical knowledge can be directly applied.”
It looks more like human geriatric care. To keep the gorillas healthy, zoo veterinarians not only turn to technologies and drugs developed for humans, but also consult medical specialists such as cardiologists, radiologists, obstetricians and dentists.
Winston, for example, takes four common heart medications that people also take, although in different doses. (He weighs 451 pounds.) The heart monitor he received, which is smaller than a flash drive, is also implanted in people. Winston received his annual flu shot this fall, and is undergoing physical therapy for arthritis.
“We are looking to provide comfort to animals later in life,” said Dr. Kinney.
That wasn’t cheap: There were about 20 doctors, technicians and other staff in the operating room when Winston received his new monitor. But the San Diego Zoo Wildlife Alliance, parent organization for the zoo and safari park, covers Winston’s care through its annual operating budget. Donors and partners cover some additional costs.
“None of our animals have insurance, and they don’t pay their bills,” said Dr. Kinney.
Some of Winston’s longtime caretakers, called wildlife conservation specialists, have retired. But Winston, who has achieved silverback status in age, stays on the job, managing his “troop” of five gorillas, keeping the peace and intervening in fights when necessary.
“He’s a gentle silverback, an incredibly patient father,” said Jim Haigwood, the curator of mammals at the San Diego Zoo Safari Park. “Her youngest daughter, she will still allow food to come out of her mouth.”
Twice the zoo has introduced females with sons into the troop, which in the wild can lead to infanticide. But Winston’s caregivers believed he would accept, and he did.
“He raised those boys as if they were his own children,” Mr. Haigwood said. (However, when they become rambunctious teenagers, they are rehomed in their own homes, an option that can sometimes be envied by human parents.)
Winston, a western lowland gorilla native to Central Africa, arrived at the San Diego Zoo in 1984. He enjoyed good health until 2017, when his keepers noticed “a general slowdown,” said Dr. Kinney, who arranged Winston’s first echocardiogram.
The test showed only “a couple of subtle changes, nothing alarming,” said Dr. Kinney. Everyone breathed a sigh of relief. Normal aging.
Then in 2021, the entire troop gets sick with the coronavirus, probably sent by someone. As with human patients, age is important.
“Winston was the most severely affected,” said Dr. Kinney. “He had a cough, quite significant dizziness, loss of appetite.” He started holding on to things while walking.
After an infusion of monoclonal antibodies, Winston recovered. Now the whole troop is vaccinated and strengthened against the virus.
But while Winston was being treated, veterinarians and human doctors ran other tests that found health issues. Winston’s heart began to pump less efficiently; that led to a daily regimen of blood pressure and heart medications hidden in his food, and in the implanted monitor. He also takes ibuprofen and acetaminophen for arthritis in his spine, hips and shoulders.
Even more alarming was a CT scan and biopsy that revealed a cancerous tumor affecting Winston’s right kidney. That prompted the kind of risk-versus-benefits conversation that should inform decisions about invasive treatment for older patients, but which is often skipped for humans.
“Are we doing a surgical procedure?” Dr. remembered Kinney wondering. “The big concern is, what will the recovery look like?” After considering Winston’s age and life expectancy, and determining that the tumor was not growing, “we felt comfortable with continuing to monitor him,” she said.
Right now, “we’re in a good balance,” he said. That’s not strictly a medical issue, but reflects Winston’s ability to lead his troops — including one woman, Kami, with whom he’s had a “very devoted partnership” for 25 years, says Mr. Haigwood.
Some aspects of healthy aging may come more easily for zoo primates than for humans; their keepers only provide healthy options. “They don’t smoke,” said Marietta Danforth, the director of the Great Ape Heart Project, a research effort at the Detroit Zoo. “They don’t eat cheeseburgers.”
Winston’s vegetarian diet consisted mainly of tree branches and root vegetables. The half-acre Gorilla Forest where he lives, with its hills and ponds and climbing structure, promotes exercise.
However, geriatric care necessarily involves end-of-life decisions. Winston may die a natural death one day Ozzya gorilla who died at Zoo Atlanta two years ago at the age of 61, or Colowho was 60 years old when he died at the Columbus Zoo in Ohio in 2017.
But if the quality of his life declines, if he stops interacting with the troop and his caregivers or begins to suffer, it parallels the end of human care. Even in California, with its medical aid in dying law, euthanasia for humans remains illegal. This is an option for Winston.
“It’s a privilege in veterinary medicine,” said Dr. Kinney. “It also comes with great responsibility.”
If Winston’s doctors, specialists and caregivers conclude, after extensive discussion, that a painless death is preferable to a shortened life, “it’s a very quiet process,” said Dr . Kinney. After an overdose of anesthesia, he said, “within minutes, there was cardiopulmonary arrest.”
About 350 gorillas – and 930 great apes in total, including bonobos, orangutans and chimpanzees – live in US zoos, said Dr. Danforth. No matter how well they are cared for, some animal rights activists and primatologists argue that they do not belong in zoos.
But even the People for the Ethical Treatment of Animals, whose position is that wild animals belong in the wild, acknowledged in an email that zoos like San Diego’s, which is accredited by the Association of Zoos & Aquariums, are meet high standards of animal care.
Winston “has had high-quality years,” said Dr. Kinney. The gorilla has become a beloved media personality. San Diego will mourn his loss, whenever and however it happens.
Right now, “we want to make sure Winston lives a good life, that he’s fulfilled,” said Dr. Kinney. “We have a good understanding of what makes Winston Winston.”
