Caring for senior zoo citizens getting trickier

updated 2:09 p.m. ET June 22, 2008

Even as a youngster, Rollie looked older and wiser than his years. His white mustache sprouted longer by the month, until it flamed from his cheeks like a German kaiser's.

In the last few years, though, the tribulations of age — not just the appearance of it — have begun catching up with Rollie. His keepers are reminded each time they get a look past the Emperor Tamarin's flowing whiskers and into his jaws.

The tiny monkey, used to crunching away on raw sweet potato, has surrendered all but six of his 32 teeth to the toll of time.

At 17, Rollie — a resident of Chicago's Lincoln Park Zoo — is a senior citizen of his species. In the Amazon he almost certainly would never have made it this long.

In captivity, he's got plenty of company.

The Golden Years have arrived at the nation's zoos and aquariums, taking veterinarians and keepers, along with their animals, into a zone of unknowns.

Do female gorillas, living in to their 40s and 50s, experience menopause?

Can an aging lemur suffer from dementia?

How do you weigh the most difficult choice — between prolonging pain and ending life — when the patient is a venerable jaguar who feels like a member of the family?

'How old do animals really live?'
All those questions hang on a larger one that, until recent years, has been left to educated guesswork.

"How old do animals really live?" says Sharon Dewar, a spokeswoman for the Lincoln Park Zoo, whose keepers adjusted to Rollie's toothlessness by serving him soft-cooked veggies. "That's the million-dollar question."

Zeroing in on the answer takes years of tracking births, deaths and the age of animal populations. But zoos, which have pooled information since the 1970s, are drawing conclusions. For example, records show that the median age of Siberian tigers in zoos has reached 15 years old, up from just over 11 in the two decades ending in 1990.

Eric Gay / AP George just can't move around like when the nearly 38-year-old was a little tapir.

The increase in animal longevity is no mystery. Just as with people, health care for animals has become much more sophisticated.

At the San Antonio Zoo, keepers noticed that George, a 37-year-old tapir, was slowing down. His legs seemed stiffer and he had trouble getting up. The diagnosis was clear: arthritis.

First they put him on dietary supplements, then a prescription. Finally the zoo called in a specialist who performed acupuncture on George, inserting tiny needles at various medians in an effort to ease the pain.

Since then, George "acts like he's five years younger," says Rob Coke, the zoo's senior staff veterinarian.

Even as zoos improved care, they've also become much more careful and cooperative in managing animal populations, to make decisions about breeding. Keepers focus on more than just keeping animals healthy, creating habitats and social environments that will make them happy and less-stressed.

The result is more robust animals who live longer because life in a zoo or aquarium grants animals an exception to nature's laws of survival.

MORE FROM SCIENCE

Science Section Front

2,000-year-old cream shows aristocrat’s taste Bridging the science gap San Andreas fault giving off mysterious tremors Plant doesn't worry about rain — it waters itself Methanol could power artificial muscles Endangered species’ DNA stored at museum Scientists lay out gene map of Korean man It's official, beloved polar bear Knut's a Berliner   Video: Croc fossil found in Brazil Scientists create human sperm from stem cells Science Section Front   Add Science headlines to your news reader: