Zoo battle of the bulge

Nigalya, a red panda, gorges on grapes. But workers at the Chattanooga Zoo have the 11-year-old mammal on a diet and limit him to a mere five grapes a day.

Penelope, a potbellied pig, is on a regimen of kale and spinach because she needs to shed 20 pounds. And Pooh, a raccoon, is about double her weight, zoo officials said.

“Some animals have a hard time keeping weight off, so sometimes we have to tailor diets. We start cutting out high fat and high calories,” said Dr. Tony Ashley, a veterinarian at Animal Clinic East and for the Chattanooga Zoo. “It can be difficult.”

Zookeepers here, like others across the country, are trying to control animal weight. Wild animals in captivity don’t have to hunt or roam and are sometimes sedentary.

“Zoo animals don’t have to hunt for food and mates and protect their territory like wild animals do, so they don’t get the exercise they need,” Dr. Ashley said.

Obese animals, primates in particular, are susceptible to the same health problems faced by overweight humans, including diabetes and heart disease, zoo Director Darde Long said.

Zoos across the country are lightening their animals’ diets to guard against obesity.

At Chicago’s Brookfield Zoo, staff members put some of the gorillas and bears on Weight Watchers’ diets, according to The Associated Press. Keepers at the Indianapolis Zoo offer sugar-free Jell-O to their polar bears.

Some primates at Zoo Atlanta now get Crystal Light instead of fruit juice, CNN reported.

At the Chattanooga Zoo, most animals are at a healthy weight, Ms. Long said. But zookeepers are altering the diets of the three overweight animals.

Pooh is one of four raccoons but is the only one with a weight problem. To get her weight down, her keepers will either start feeding all the raccoons by hand or cut back food for the entire group, Dr. Ashley said.

Zoo animals live longer than their counterparts in the wild because of improved medical care as well as a lack of predators, viruses and parasites found in the wild. But as zoo animals age and if arthritis develops, they may become more sedentary and gain weight.

“Animals have a tendency, just like humans, to eat too much,” said Barbara Lintzenich, curator of nutrition at the Cincinnati Zoo and chairwoman of the nutrition advisory group for the Association of Zoos and Aquariums.

The Chattanooga Zoo supplements animal diets with specially formulated mixtures, such as monkey chow for the primates and Nebraska Brand Frozen Feline Diet, a large chunk of meat embedded with nutrients, for the big cats, Ms. Long said.

Zookeepers also provide daily “enrichment” — mental and physical exercise.

To provide enrichment without adding calories, zookeepers often will serve food from the animals’ regular diets in different ways to stimulate them.

For example, food may be scattered around the primate enclosures so that gorillas will have to search for their meals and exercise some. Food may be tied up on a string so animals have to jump or reach for it.

Zookeepers have come up with other creative ways of enriching animals’ daily routine without using food.

“The big cats love odd scents, so we may put coffee grounds or spray perfumes we don’t like in places around their pen,” Ms. Long said. “Or we’ll move the ‘furniture’ in their enclosures around to keep things interesting.”

The exception is the hyena, Frankie.

“He’s old and very sensitive to change,” Ms. Long said.