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Bon appetit - new zoo nutritionist has 18,000 mouths to feed

This article first appeared in the St. Louis Beacon, Nov. 30, 2009 - The St. Louis Zoo has added another first. A gift of $1.5 million from the William R. Orthwein Jr. and Laura Rand Orthwein Foundation has created an endowed position of animal nutritionist. Of about 200 zoos in the United States, only 14 have animal nutritionists on staff. Only four, one of them the St. Louis Zoo, have associate nutritionists.

"To the best of our knowledge, this is the first time that the position of animal nutritionist has been endowed at any zoo," said Jeffrey Bonner, president and CEO of the Zoo.

Get to know Debra Schmidt

Debra Schmidt has always wanted to work for the St. Louis Zoo. After graduating from Lafayette High School, she went to the University of Missouri-Columbia for a bachelor's  in animal sciences. She then got her master's in reproductive physiology at Louisiana State.

While working at the Purina Farms Pet Care center in Gray Summit, she became interested in nutrition. She obtained her doctorate in animal science with a focus on nutrition from the University of Missouri-Columbia, writing her thesis on lemur nutrition.

After 3 1/2 years at Lincoln Park Zoo in Chicago as a research nutritionist, she went to work at both the San Diego Zoo and Wild Animal Park as a clinical nutritionist.

Schmidt is now busy acquainting herself with the Zoo and its collection.

Debra Schmidt is the Zoo's endowed nutritionist. She returned to her native St. Louis five months ago to oversee the diet of the 18,000 Zoo residents. A Zoo nutritionist is responsible for feeding diets tailor-made to the needs of animals as diverse as elephants and iguanas.

She administers an annual grocery list that includes:

  • 10 tons of carrots
  • 400 cases of bananas
  • 475 cases of apples
  • 1,000 cases of kale
  • 13,000 bales of hay
  • 15 tons of mackerel
  • 20 tons of herring
  • 5 tons of smelt
  • 1.5 tons of squid
  • 1.2 million crickets
  • 675 pounds of earthworms
  • 1.625 million mealworms
  • 22,000 adult mice
  • 6 tons of primate biscuits
  • 85 tons of herbivore pellets

And much, much more.
A few of the largest animals get the "lion's share" of some of these groceries. For example, Raja receives 16 pounds of elephant pellets, eight pounds of produce and three bales of hay (about 70 pounds each) daily. A spider in the insectarium might get a couple of crickets every week.

While Schmidt administers this vast commissary, all food preparation and ordering are carried out by the staff headed by Scott Runnells, Zoological Manager.


The basic diet for many animals is nutritionally balanced commercial food mixes, such as the primate biscuits (that come in different flavors) and the herbivore pellets. One feed supplier is Mazuri, a division of Purina, that supplies zoos and pet stores all over the country. In the storeroom are stacks of bags containing rhino food. The huge walk-in freezer is full of fish for the sea lions and penguins--among others.  For the Zoo's other carnivore residents, the freezer is stocked with chubs of ground meat carefully mixed with vitamins and minerals.

Produce, all of it restaurant quality, is used to provide a rich, varied diet.

"We try to mimic an animal's life in nature as much as possible," says Jack Grisham, vice president of animal collections.

In the outside Jungle of the Apes, the keepers put foods in different places each day, so the animals must forage for their food. They are fed at different times each day, so they don't get accustomed to being fed. In nature, they eat when they find the food. They have to work for their living.

Schmidt believes that variety of diet helps animals thrive. "I think it's huge for psychological stimulation. It's not extra. It's built into their diet."

She decides what foods can be used for variety. For example, if cantaloupes are available in the summer, what animals would enjoy them, and how much should they be fed? Working with keepers and curators, they ask how these melons can be presented. Should they be cut into large or small chunks? How do you ensure that each animal gets its fair share? Maybe a luscious wedge will be the reward for a certain behavior, such as going indoors at a signal from a keeper who wants to clean the animal's enclosure.

A note on the bulletin board of the kitchen in the Orthwein Nutrition Center says "BH-ribs." Schmidt has incorporated ribs into the diet of carnivorous birds like vultures and eagles. Basically, these animals are fed a diet based on that of the most carnivorous of creatures, the cat. But ribs are an enrichment that gives them exercise. They have to hold the ribs down at one end, while teasing out the meat between the bones. The keepers like seeing their charges enjoy their food. The public gets a little education.

Next will be a "rabbit day" every couple of weeks for large carnivores. "An enthusiastic carnivore will eat every speck of the rabbit's carcass, including internal organs and bones. The organs are especially important because they contain vitamins and minerals not found in muscle meat. Bones of course provide even more minerals." Schmidt has to calculate how much ground meat a rabbit will substitute for, because she doesn't want to overfeed.

Zoo nutrition

Of the 18,000 zoo animals, 12,000 live in the Insectarium.

The staff delivers food every day of the year. Some of it is pre-mixed, like fruit slurry for the butterflies. The keepers prepare other foods. For example, the American burying beetle, an endangered species the Zoo is engaged in protecting, eats mealworms and waxworms. But when breeding, they need a small animal carcass like a quail because they feed their larvae regurgitated meat from the decaying animal.

Ed Spevak, curator of invertebrates, explains that many of the insects eat from their surroundings. The honeybees in the Zoo are allowed to go out and forage in the park. The bumblebees stay home and are fed pollen from Whole Foods.

Leaf-eating insects, like walking sticks and katydid, eat "browse" collected from Forest Park in the summer. In the winter they get boxes of blackberry stems and leaves from Oregon.

Some insects live surrounded by food. Derbyana beetles from Africa burrow inside a mixture of soil, organic plant matter, chopped up veggies and fruit, and dung from bantangs, a kind of cow.

Chacun a son gout (to each his own).

These enrichment practices depend upon teamwork. The nutritionist works with curators, keepers and vets to keep the animals healthy. She needs to know which carnivores like dining on rabbits, and if they do indeed eat the whole animal. The keepers of fish-eaters need to make sure that each of their charges gets one fish daily that has a vitamin supplement tucked inside. The supplement is necessary because fish start losing vitamins E and B1 (thiamine) as soon as they are caught.

The starting point for animal diets, explains Schmidt, is nutrition research on livestock animals from the agriculture and pet-food industries. So if she needs to feed a monogastric (single stomach) herbivore like a rhino, elephant or zebra, Schmidt consults dietary research on horses. For ruminants (four chambered-stomachs) like gazelles, antelopes and giraffes, she uses references on cows. If Schmidt has questions about any species, she can consult other zoo nutritionists or university researchers. She has an international network of fellow professionals dedicated to the zoo's conservation and preservation goals.

But, of course, the science of learning about how animals live in the wild is constantly evolving. So knowing exactly what food a particular animal eats in nature helps the nutritionist decide what available foods the Zoo can substitute. If an animal eats lots of leafy greens in nature, will kale or romaine be a better substitute? Maybe an occasional spinach treat?


As a clinical nutritionist, Schmidt has helped the zoo's two pygmy marmosets gain weight. When these picky eaters moved to the St. Louis Zoo from another zoo several years ago, they were eating primarily baby cereal and bananas. Knowing that New World monkeys, such as the mamosets, need more vitamin D than other primates, Schmidt worked with the keepers to wean them onto a balanced primate diet. They are now gaining the needed weight.

A research program is on the drawing board. In the past, Schmidt has studied cholesterol levels in wild gorillas and orangutans as compared to those in captivity. In captivity, total cholesterol levels ranged from 100 to 500. But in samples from wild apes, the cholesterol level hovers consistently around 200. Explaining the discrepancy might be very important for health in Jungle of the Apes.

Associate nutritionist Erin Kendrick oversees some research projects as she consults for other zoos.

For now, Schmidt is also busy settling into life back in St. Louis, close to her parents and a sister. "I had never even been to the new Busch Stadium," she says. "Folks in other cities just don't understand how we feel about the Cardinals."

At present she lives in a downtown loft with one cat, but plans to buy a house that can hold a dog also. She wants to try being a foster parent for the Humane Society.

As the Zoo motto says, "Animals always."

Jo Seltzer is a freelance writer with more than 30 years on the research faculty at the Washington University School of Medicine and seven years teaching tech writing at WU's engineering school.