Behind the Scenes During Zoo Feeding Time

Brookfield Zoo Staffer Preparing Food
Jim Schulz, Chicago Zoological Society
A Brookfield Zoo employee prepares food for the animals.

Although zoo animal diets are often made from basic ingredients like produce and meat, there are also lots of manufactured products, particularly since the 1990s, which is when Watts says a lot of the basic research in zoo nutrition really got going. These foods can be quite specialized. For example, primate chow and biscuits come in different shapes, textures and flavors, as well as different compositions, like high fiber, growth or maintenance. There are special diets for marmosets, because they need much more vitamin D than other primates.

Still, it's not all science — because it doesn't matter how nutritious something is if it doesn't get eaten.

Variety Is the Spice of Life

"I like to say I feed 3,000 toddlers," Watts says. "Everybody's got their own taste buds."

So there's also an art to it. Sometimes it involves hiding the nutritious stuff inside the tasty stuff, or soaking chow in a little fruit juice. Sometimes it means coming up with a different nutritionally complete formula for each animal, like Watts had to do for the zoo's binturongs.

Binturongs eat both fruit and meat in the wild, so you'd think they would have broad tastes and be easy to please... but apparently not. "The individuals have very specific tastes," she says. "I have a basic diet, but then all the veggies are different, because this one will eat carrots and this one doesn't, this one will eat broccoli, this one will eat squash but it has to be steamed."

Zoo Nutrition Bear Eating Fish
Jim Schulz, Chicago Zoological Society

This attention to the animals' tastes isn't just because you can't force them to eat — it's that Watts considers it part of her job to make their meals enjoyable and interesting. One way to do that is to make sure their meals are a little different every day.

"For a lot of them, we have them on some sort of a rotation," she says. "We separate produce into fruits, veggies, starches — corn, sweet potato and potato — and then greens. They change on a daily basis to give variety." This way, calories and nutrition balance out over the course of a week, but the diet isn't as monotonous as if the same combination was served every day.

Watts knows these efforts are worth it because she often sees that the animals notice the difference. She recalls that when she first started her job, the pygmy hippo, Adele, was just getting grain, hay, carrots and sweet potatoes every day. Watts started her on a rotation of produce. "By the second day, she was running into her holding area because she was excited about what she was going to get to eat," she says. "That's what I want [them] to do. It's not just eating food — it's something that's interesting for them too."


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