Each animal at Lincoln Park Zoo receives an individually tailored diet based on feeding ecology, natural history, age, sex, body condition, and weight—but creating the perfect diet on paper doesn’t always translate to reality. Zoo animals ultimately choose whether or not to eat the food provided by nutrition staff, who must strike a healthy balance between food preferences and nutritional goals.

A Blend of Art and Science

The Science

Nutrition staff follow species-specific guidelines outlined by the Association of Zoos and Aquariums (AZA) and the Nutrition Research Council (NRC), as well as recommendations from peer-reviewed articles. Then, they design and review internal diets using a zoo-based dietary formulation software. Not all species have dietary recommendations. In that case, nutrition staff leverage their expertise working with similar species to create a nutritious diet from scratch. Most animals at Lincoln Park Zoo receive a base diet that meets all their nutritional goals, as well as supplemental produce, meat, insects, and other foods.

Every diet is reviewed and, if possible, enhanced on a yearly basis.

The Art

If the animal does not eat its formulated diet, nutrition staff head back to the drawing board to create a new diet that entices the individual while meeting its dietary needs. Sometimes, zoo nutritionists put on their chef hat and create new recipes to help with weight gain.

A Few Lincoln Park Zoo Original Recipes:

  • Yummy Bars (for primates): soy protein powder, oat bran, whole wheat flour, wheat germ, salt, raisins, dried cherries, dried blueberries, dried apricots, silken tofu, apple juice, dark brown sugar, eggs, and peanut butter
  • Goat Bars: soy protein powder, Mazuri® Wild Herbivore Boost®, pumpkin puree, oatmeal, and sweet potato-flavored baby food

Eating Their Browse

Browse refers to any leafy plant material provided to browsing animal species, such as rhinos, giraffes, beavers, goats, colobus monkeys, and Francois’ langurs. Browse can be served fresh, frozen, or as a silage (fermented fodder), and is often provided by the zoo’s very own Horticulture staff.

Why Is Browse Important

By providing the appropriate animals with browse, nutrition staff can encourage specific-specific behaviors, such as foraging, that enhance their welfare. Browse also contains vital nutrients that hay and “complete” foods lack.

Is It Safe?

The zoo’s Horticulture staff identifies and evaluates every browse species before it is give to an animal. Nutrition staff maintains a “safe browse list” that is reviewed by the director of horticulture and director of veterinary services in order to ensure the safety of zoo animals.

Animals Depend on People Too

Animals Depend On People Too! When you ADOPT an animal, you support world-class animal care by helping to provide specially formulated diets, new habitat elements, and regular veterinary checkups.


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