Insider Info

So what exactly do you give a thirsty gorilla? How about a hungry elephant? Well, at one zoo, the gorillas enjoy the occasional cup of herbal tea. And the elephants love fresh, whole grapefruit.

Maybe the better question would be: how on earth do you find out what these animals want to eat? At this particular zoo, it's animal nutritionist Michelle Shaw's job to find out.

"Each animal is like a black box," she says. "There is very little research out there on what many of these animals eat or what substitutions can be made."

Budgetary concerns and availability of food often mean that animals must have diets that differ from what they would normally eat in the wild. "We have to formulate diets for everything from fish to elephants," says Shaw. "We do this by designing according to the animal's digestive system."

For example, an elephant has a similar digestive system to a horse. "The inside of an elephant is similar to that of a horse, so that's where we begin," she says. Exotic birds may get feed that is similar to domestic chickens.

But many animals have specific needs that must be addressed. "Our gorillas need an increase of vitamin B, and some other animals are sensitive to iron. We have to avoid toxic levels," says Shaw.

The actual location of the exhibit can also affect the animal's diet.

"Some marmosets are sensitive to levels of Vitamin D. If they're in an indoor exhibit, then we have to give additional vitamin D." That's because animals absorb vitamin D by exposing their skin to the sun.

A lot of the diet formulation is done by trial and error. "It would be nice if there was more information to go by," says Shaw. "The frustrating part is that there just isn't a lot of research in this area."

She explains that zoo nutritionists can't simply look at what the animals are eating in the wild. "In many zoos, we are dealing with an aging population. The animals get to be much older than if they were in the wild. What do you feed an animal with no teeth?"

If the toothless animal was in the wild, it simply wouldn't survive. "We have to figure out how to keep feeding and maintaining that animal."

Animals bred for meat also need great attention paid to their nutrition. "It's probably more important than genetics," says Ronald Lemenager. He is a professor of animal nutrition at Purdue University.

"Reproduction is driven by nutrition. If you don't feed the cattle, they don't have babies."

In fact, the nutritional requirements of pregnant cows are closely monitored. Like humans, at different stages of the pregnancy they require different nutrition. "As the cow approaches the last three months of pregnancy, its nutrient requirements skyrocket."

So how do ranchers give their cows optimum nutrition, which in turn ensures healthy saleable calves? Many turn to an animal nutritionist for help examining and altering diets.

"Depending on the forage quality, we may have to feed grains. The amount depends on the nutrient quality of the food and the size of the cow," says Lemenager.

So if a larger cow requires more grain, why would a rancher opt for having a herd of the bigger breeds of cows? "It's simple," says Lemenager. "A bigger cow produces a bigger calf."

When it comes to serving up a steak, one size cow doesn't fit all. "A 16-ounce T-bone steak comes from a large animal. It's not the same animal that gives a seven-ounce steak," he explains. Because of differing demands in the market, different types of cattle are raised.

And not all steaks are the same. Why are some tender and others tough as nails? It can be as simple as what the animal ate when it was raised. "A steer that is fed on grass is tougher and less juicy than one that is fed on grain and forage," explains Lemenager. "It's possible to change the juiciness by changing the diet."

Jane Goodridge is an animal nutritionist who works with pig ranchers. She spends her time assessing pig diets and recommending changes that will lead to healthier animals.

"You have to know the nutrient needs of pigs and know the producer," explains Goodridge. From all the information she gathers, Goodridge designs diet plans.

Whether working for a private feed company and promoting a product, or working as a consultant from a university, animal nutritionists aim to help animals and help producers maintain a viable operation.

"The producer stands to make money by adapting to new technology," says Lemenager. "But a nutritionist's work is also about doing what's right for the animal. It is about making an animal's life more comfortable. Nutrition is a big part of that."

"This field is always a challenge," agrees Shaw. "But in the end, my job is to keep rethinking diets, and making conditions better for the animals."