Like many aging baby boomers, the Golden Girls of the Dallas Zoo are moving around slower, popping pills to ease their aches and pains, and watching their waistlines.

WILLIAM DESHAZER/DMN

Hercules, one of three senior gorillas at the Dallas Zoo, enjoys frozen treats by day but needs a heating pad by night. Medical advances have helped zoo animals live longer, and zoos are using more technology and spending additional time addressing the needs of their elderly.

Jenny, the oldest gorilla in captivity at 55, can't see well, so zookeepers place fruit and frozen treats in easy-to-find spots.

Kamili, 25 and the oldest okapi in captivity, walks around on hay to give her aging legs a break and prevent falls.

WILLIAM DESHAZER/DMN

Kamili, the oldest okapi in captivity, walks around on hay to give her aging legs a break and prevent falls.

Bonbon, a 49-year-old chimpanzee, is hand-fed to make sure she eats enough.

Thanks to medical advances, zoo animals are getting older in Dallas, Fort Worth and across the country. And as animals live longer, zoos are using more technology and spending additional time to address their needs – from X-rays and ultrasounds to hysterectomies and endoscopies.

Now more than ever, zoo animals live a much different life compared with peers in the wild.

"There's no idyllic wild state," said Steve Feldman, spokesman for the Association of Zoos and Aquariums. "There are many instances where they're living longer than they would in the wild."

Zoos say they're committed to providing cradle-to-grave care, so they're focusing on preventive medicine and addressing animals' psychological needs – even bringing in specialists when needed.

"We have an opportunity to maintain the quality of life as best as we can for every animal," said Dr. Mary Denver, president of the American Association of Zoo Veterinarians. "We have a responsibility to every animal."

It's difficult to track data showing the age of the country's zoo animals. But the aging animal population is evident from San Diego to Columbus, Ohio, to Dallas.

Dallas' Jenny is the grande dame of captive gorillas.

For her advanced age, Jenny is in good health, only taking multivitamins and a joint supplement – a powder that's mixed with applesauce. But the age is taking a toll: Officials say she is showing early signs of cataracts, and she eats Activia yogurt to calm her irritable stomach.

Two fellow gorillas in their 40s also are feeling the effects. Timbo takes arthritis medication, and Hercules uses a heating pad at night to ease his bad back.

Older gorillas are more likely to lounge around, so zookeepers give them less food.

"We don't want to get them obese," said Dr. Todd Bowsher, the zoo's mammal curator.

When zookeepers tossed out fruit and frozen treats last week, Jenny, Hercules and Timbo took a leisurely climb up a hill and scooped up their loot. Jenny retreated to a fig bush, where she enjoys picking and eating the figs.

Sometimes fellow animals help each other out. Chimps occasionally deliver treats to Bonbon, the 49-year-old chimpanzee, including her daughter, Koko.

Kamili the okapi is enjoying semiretirement after zookeepers noticed she was getting stiff after she roamed in her exhibit. The giraffelike animal typically spends a couple of hours each morning on display, then retreats to a private enclosure.

Better training among animal doctors is critical to animal longevity. Many zoos have full-time vets and full-time nutritionists to monitor their animals.

When zoos encounter mystery ailments, they swap details with each other. They also turn to veterinary schools, which are producing more specialists, such as cardiologists, ophthalmologists and surgeons.

"Zoo veterinarians are sort of generalists; we have to know a little bit about a lot of animals," said Dr. Michael Barrie, director of animal health at the Columbus Zoo. "If it comes down to a more serious problem, then I have in my disposal specialists that I can call upon for advice or to help me with procedures."

Aging animals give zoos and scholars a chance to expand zoological research, such as treating osteoarthritis. Zoo vet association conferences include sessions on topics such as geriatric animal care, Dr. Denver said. At the Dallas Zoo, Jenny and Timbo were part of a national study on gorillas and menopause.

But death is inevitable, and the ending can be tough on zoos and communities because of the animals' celebrity status.

The Fort Worth Zoo received condolences from visitors and zoos across the country after the death of an old white tiger, said Ron Surratt, the zoo's animal collections director. Neela, 18, was euthanized in 2003 because of deteriorating health.

The Dallas Zoo has also had to say farewell to elderly animals, including Hildy, the nation's oldest giraffe, who was euthanized last year.

"You feel like you've done everything you can for them," said Megan Lumpkin, a senior zookeeper at the Dallas Zoo. "You'll miss them, but they had a good life."