Some days Joice wakes a little stiff. Her hips especially can give her some trouble.

Getting old can be a big pain, and a lot of little pains.

Her physical therapist puts her through regular stretching exercises to loosen her up and help her keep up with her daily routine. That includes snacking on fruit, napping and maybe climbing the walls.

Joice is a chimpanzee. At 51 years old, she’s not just the Maryland Zoo’s oldest of 15 chimps, she’s the Baltimore facility’s oldest mammal.

“We watch her movements every day to see if she’s stiff,” said Melissa Somogyi, an animal keeper working with Joice. “She has a lot of choices. If she wants to come out and do exercises we can tell it helps.”

Physical therapy is becoming a bigger part of the wellness program the zoo has adopted to ensure the animals age as comfortably as possible. The practice takes a few forms and is now used in other zoos, including those in San Diego and Seattle.

A 2018 article published in the scientific journal “Animals” suggested training the geriatric residents at the nation’s zoos to do physical therapy to keep them active.

The practice has since become more common across the country because zoos tend to share success stories, said Bethany Krebs, a zoo scientist and author of that paper. Zoos had borrowed the idea from veterinarians who began using physical therapy in dogs, cats and horses around 20 years ago, Krebs said.

Krebs said involving zoo animals in their own care pairs well with other work to improve the quality of life there, and often means zoo animals live longer than those in the wild. Zoos have adopted changes to habitats, diets and socialization practices, in addition to medical care.

“Physical therapy is often simple exercises aimed at strengthening or stretching, which makes it very safe and low risk for the animal,” she said, adding, “Nearly every zoo will have at least one animal of a record-breaking age.”

Median life expectancy for chimps is about 40 years old, though they’ve been known to live into their 60s in zoos. And there are plenty of species on the Maryland Zoo’s senior roster. They include a 16-year-old giraffe named Caesar, about a year past the median life expectancy, and a 48-year-old African elephant named Anna, more than eight years beyond the median.

Joice the chimp was diagnosed with age-related hip arthritis a few years ago. When it began limiting her mobility, zoo staff worked with a human physical therapist to design the daily routine. Joice learned that when trainers tap the fence with a wooden dowel, she is supposed to stretch out a leg.

In return she gets a hunk of fruit from a bucket, which this wise but not entirely generous older gal continuously defends from her very interested roommates.

The scheme, however, has had its intended effect. Not long after starting the routine, Joice had improved range of motion and a boost in energy and ability to interact with other chimps, said Dr. Ellen Bronson, the zoo’s senior director of animal health, conservation and research.

“As an added benefit,” she said, “we don’t have to constantly administer medications that we would have otherwise.”

Physical therapy doesn’t replace medical care. The animals have regular physicals with blood tests and imaging, just like humans. Some still get regular doses of Advil for those aches and pains. But because they can’t use words to tell someone when they don’t feel well, the staff also monitors for changes in how animals walk or poop, or even differences in the hoots and howls that are the native languages around here.

When routines are clearly disrupted, the caretakers talk to the behavioral and medical staff and develop a plan. The staff also monitors for symptoms related to circulating viruses, such as COVID-19 and avian influenza, which zoo animals can catch from trespassing wild animals. The most vulnerable animals, such as the big cats, are vaccinated against the coronavirus.

Staff can tell when Anna the elephant is a bit stiff or achy because she tends to lean on the enclosure. Soft sand has already been added atop her four horse mats that make up her sleeping quarters. But now, if she is amenable, she does some exercising.

That means getting Anna to balance her 8,370 pounds on three feet instead of four for several seconds at a time. How, one may wonder, does trainer Craig Whalen get an elephant to do that?

Sweet potatoes. She gets a handful of this tasty treat, or equally tasty carrots, when she responds to commands from the other side of a fence. It’s called positive reinforcement training, and it also works to get elephants, chimps and other animals to go along with a range of medical interventions.

“Foot,” Whalen says, and Anna lifts a foot in the air and opens her mouth.

“Steady,” he says and she holds her foot up.

“All right,” he says and she puts it down.

The trainers also take her for walks on different surfaces, like slight uphill climbs that build muscle strength, said Mike Weaver, the elephant manager. He said a lot of attention is given to Anna’s toenails to ensure they are trimmed and she has no other issues in carrying around all that weight. (Sorry, Anna, we know it’s not polite to talk about that.)

“We try to flex those joints as much as we can,” Weaver said. After about 10 minutes, he said, “She’ll probably eat some hay and take a nap.”

meredith@thebaltimorebanner.com