Aging Apes and Elderly Elephants

At the Los Angeles Zoo, Herman, the Indian rhino, is almost blind from cataracts. Gita, an Asian elephant well into middle age, has severe arthritis. Time has taken its toll on the kidneys of Indira, the 14-year-old tiger. Senior tamarins and marmosets are bedeviled by gum disease. Koo, a white-cheeked gibbon of a certain age, has developed diabetes.

“More than a fifth of our mammals are very old for their species, and more than half are past breeding age,” staff veterinarian Cynthia Stringfield said of the zoo’s 1,200 mammals. “And we see in aging animals a lot of the same things aging people have--arthritis, cancer, cataracts, diabetes, heart disease.”

As the zoo population ages, in Los Angeles and in much of the world, veterinarians and other staff members are spending more time and money on a panoply of ills plaguing their elderly.

Zoo veterinarians worry about the prostates of their older primates and canines, including wolves, coyotes and foxes--all prone to disorders of that troublesome gland, including cancer.

If they live long enough, animals may even develop something similar to Alzheimer’s disease, as evidenced by their apparent failure to recognize longtime keepers and other once-familiar faces.

As a result, zoos increasingly are turning to the widening repertoire of diagnostic and treatment options for animals based on what is available to older humans, from CT scans to hip replacements.

“A geriatric specialty is just forming,” said Wilbur Amand, current president of the World Assn. of Wildlife Veterinarians.

In a sense, the aging of zoo animals reflects success in protecting them from the multiple dangers of life in the wild, as well as increasing success in caring for them in captivity.

“We deal with geriatrics because most of these animals are doubling and tripling their life spans in captivity,” said Eric Miller, head of animal health services at the St. Louis Zoo and immediate past president of the wildlife veterinarians’ group.

According to Miller, the typical gazelle on the Serengeti is lucky to live to age 3 or 4 before it is felled by a lion or hunger. In zoos, many gazelles reach their teens, thanks to increasingly sophisticated care from their keepers and vets as well as better nutrition.

“I think we’re all in the same boat because we know how to take better care of these animals,” said Stringfield, speculating on why more zoos have more older animals.

“Every zoo has some animals that are approaching maximum longevity,” said Marvin Jones, who kept the animal records as registrar of the San Diego Zoo and Animal Park for almost 20 years until his retirement in 1993.

“In the old days, they might have euthanized older animals to make room for younger ones. But these days there’s a concerted effort to keep animals as long as possible, as long as they’re not suffering.”

Also, experts say, modern zoos rarely, if ever, accept young animals taken in the wild.

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Ethically repugnant to many, the trade in wild animals all but ended, at least in developed countries, in the 1970s with the rise of the global environmental movement and subsequent international agreements protecting endangered species, according to Jones and others. Today, almost all mammals and most other animals in zoos are bred in captivity or obtained by swaps among zoos (some birds and reptiles are the exception, Stringfield said).

Forty-year-old Gita, the arthritic elephant, is typical of the burgeoning senior set in Los Angeles and emblematic of the way an aging animal population is changing the face of the 162 zoos in North America supervised by the American Zoo and Aquarium Assn.

Besides elephants, rhinos and other hefty animals are especially prone to arthritis. The traditional practice of displaying animals on concrete exacerbates the problem. Most zoos now put dirt or some other more forgiving material under their animals’ feet. But after a long day of being pounded by pachyderms, the soil in the elephant compound is almost as hard as concrete. Keepers at the L.A. Zoo rototill the exhibit to make it kinder on the animals’ aching legs.

Gita also gets drugs for her arthritis.

Stringfield said she and other vets don’t like to give arthritic animals anything that will cause internal bleeding, as aspirin sometimes does. So Gita gets an elephantine 3,000-milligram dose of Adequan once a month.

Originally developed for horses, the drug stimulates the production of fluid in Gita’s joints. She gets 12 times as much as a horse, at a cost of $150 a pop. (Stringfield said the zoo pays $5,000 a year to medicate its arthritic animals.)

Gita’s medicine is injected. She balked at taking an oral drug, even when keepers used such deceptions as baking it in cakes and hiding it inside melons. And when elephants balk, veterinarians and keepers listen.

Gita gets the shot in her rump, administered with a “very long needle. . . . She doesn’t seem to mind,” Stringfield said. Had Gita not worked with humans for much of her life, she might have had to be medicated with flying syringes, needle-tipped darts shot with a carbon-dioxide pistol, a procedure Stringfield says is far more stressful.

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She said arthritis is the most common disease of aging in many zoos, including L.A.’s. Heat lamps help as does warmed bathwater. Staff members fashion beds out of tires and use pallets to get animals off cold, hard surfaces.

Sometimes, other measures are required. In St. Louis, a much loved old gorilla named Fred was in agony from arthritis, head vet Miller said. The zoo called in a human pain specialist for consultation on a treatment plan.

“Just like with humans, we started with aspirin and Tylenol and worked our way up to the big stuff,” Miller said. Eventually, Fred had to be put on morphine. When even that did not alleviate his pain, the decision was made to euthanize him.

According to Stringfield, animals are euthanized infrequently at the L.A. Zoo--and then only if they are terminally ill or if they are deemed to have poor quality of life.

This approach--in which an elderly cougar gets an artificial hip and an aging, aching elephant is cajoled into taking her medicine--is the result of the continuing evolution of an ancient institution.

Five-thousand-year-old records from ancient Sumer show that its rulers amassed collections of wild beasts, trophies of conquest with beating hearts. By the end of the 19th century, the zoo was changing from a place where humans gawked at animals in cages to a place where animals were displayed in more naturalistic settings, often separated from humans by hidden moats.

In this century, zoos have been squeezed by two forces--a growing sense of the preciousness of biodiversity and individual animal life and growing unease about the legitimacy of zoos, however well they treat their animals. Philosophically, the distinction between humans and other animals is blurring, as science reveals that we are more like them than we once thought and that they are more like us.

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Unlike humans, though, animals rarely complain, and they cannot tell you where it hurts--making the vet’s job more complicated.

According to Stringfield, animals often do not show symptoms until they are seriously ill--a trait that is useful in the wild, where signs of weakness attract predators, but not so useful in the zoo.

“We have keepers who translate for our animals,” said Charles Sedgwick, head of animal health services at the L.A. Zoo.

Last year, keeper Jami Shoemaker observed that Bruno, a 30-year-old polar bear, was losing weight. He told the vets, who began monitoring the animal.

The vets found a watermelon-sized cancerous tumor on Bruno’s liver and decided, with great reluctance, that he had to be put down.

Most animals are so adept at hiding signs of illness that often no one knows they have been sick until after they are dead. Many times, a diagnosis is made only after the necropsy, the animal equivalent of an autopsy.

Sedgwick points to the case of Ziffel, a wart hog who was found dead in his barn one April morning by keeper Richard Floyd.

Sedgwick said Ziffel “just wore down like the Grand Canyon.”

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The specific part of Ziffel that wore down was his teeth. By the time he died at age 14, four years shy of the record for a male of his species, Ziffel had only eight teeth out of a full complement of 34.

Ziffel had seemed to be eating normally and hadn’t lost weight. But the necropsy showed he was felled by “congestive heart failure secondary to depleted dentition and subsequent attrition.”

In examining the body, Sedgwick found that Ziffel had no body fat, even on his heart. As Sedgwick explained, the body needs sugar. When it can’t get it the normal way, through food, it will convert protein to sugar. If the body doesn’t get sufficient protein through diet, it will start converting its own muscle to sugar, including heart muscle.

In April, the zoo also lost Chris, a Western lowland gorilla, to heart disease that killed him without warning.

The post-mortem revealed that the grizzled silver back had a pouch in his esophagus that must have given him “heartburn in spades,” Sedgwick said, with an empathetic wince. “He would have wanted the best medication possible if he had been able to talk to us.”

Koo, the zoo’s 24-year-old gibbon, was far luckier than Ziffel or Chris.

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Last year, Koo was found to have diabetes when he was given a blood test after an outbreak of diarrhea among the gibbons. When a urine test confirmed the diagnosis, zoo doctors consulted with physicians expert in human diabetes and came up with a treatment program.

Koo no longer eats grapes and high-sugar foods. He also eats separately from his mate and his son because the youngster tends to grab Koo’s food, making dad’s diet harder to control.

The gibbon also gets a daily injection of insulin. The zoo staff has conditioned him to face his shots without fear and even to help in the process. Adapting conditioning techniques used to train dolphins and other animals that perform, Koo’s keepers taught him to stick out his arm when they arrive with his insulin.

“Luckily, diabetics are always hungry,” said Stringfield, “so we could use food rewards with Koo.” With hindsight, it was clear that he had been showing the constant thirst that is a telltale sign of the disease. “People used to call him ‘the gibbon by the water,’ ” Stringfield recalled.

The L.A. Zoo lost tiger Shankara to kidney failure in December, but her sister, Indira, is hanging in there. A special kidney-friendly cat food, developed for ordinary tabbies, allows her to eat less meat, which is hard on old kidneys.

But sometimes even the best zoo doctors can’t effectively treat their charges.

Herman, the rhino, isn’t a good candidate for cataract surgery because of his species. As Sedgwick explained, humans and primates are the only animals that have encapsulated lenses that can be removed and replaced with an unclouded prosthetic lens. Most mammals’ lenses consist of a front capsule and a back capsule. You can only remove the front capsule, but the back one may be clouded as well.

Eventually, for animals, as for humans, hearts and kidneys fail.

“Keepers are incredibly attached to their animals,” Stringfield said. When an animal dies, potluck memorial services are routinely held. At a recent service for an elderly black howler monkey named Sad Sack, keepers and vets reminisced about his pranks, including his tendency to pull the hair of nearby humans.

“We remember the good times,” said retired tiger keeper Birdie Foster, now in the zoo’s public relations department.

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At 64, “Doc” Sedgwick--who is a poet as well as a pioneering zoo veterinarian--has a more visceral understanding of aging than he did 30 years ago.

That may be why, when American bison Tanka died in 1995, he wrote a poem for the beloved old herbivore he had treated for severe arthritis.

Called “Shortgrass Prairie,” the poem gives the buffalo the voice he never had. In Sedgwick’s imagination, Tanka asks his keepers at the zoo to let him go back to the prairie that was his first habitat, his Eden:

. . . Let me nod to brothers--the Prairie Voles, to sisters--the Plains Pocket Mice.

Let me lie in the shade of the rim-rock, close my eyes while a cloister of Digger Bees chant their mantra . . .

Let me dust myself in some ancient scrape used by my ancestors.

Open the gates, my dear keepers, you’ve been kind,

But it’s time; let me walk through the gate, onto the Shortgrass Prairie.