Animal Tales

New View of Hippos


Currently, if the hippo is in the water, you can only see the top of its head when it surfaces to breathe. In the new exhibit, you’ll be able to watch the hippo move underwater.

Scat. Feces. Waste. Whatever you choose to call it, poop is a fact of life, especially for the hippopotamus, one of the world’s largest land animals. Hippos eat 80 to 100 pounds of grass per night and then spend up to 16 hours a day in the water, where they create hundreds of pounds of poop. That can be a problem if the water is in a contained area – say, a pool at the Milwaukee County Zoo – especially if you want to keep the water clear enough to see through it.

Hippopotamus Exhibit

The underwater viewing area will be shaded so sunlight doesn’t cause glare on the glass.

That’s just one of the challenges facing the planners of the Zoo’s new hippo exhibit, scheduled to break ground later this year. When finished, the exhibit will be one of eight in North America with underwater viewing of hippos. Visitors will be able to go right up to the glass of a 60,000-gallon pool, similar to the way they can view the polar bear and harbor seals underwater now. “The clarity of the water is what makes or breaks these exhibits, for sure,” says Brent Pitcher, vice president at GRAEF, a Milwaukee engineering and consulting firm that is leading the design team.

Planning for a new outdoor hippo exhibit started before the Zoo expanded the indoor hippo area in 2009. Now, that plan is close to becoming a reality as part of Adventure Africa, which will include new exhibits for the elephants, African hoofstock, hippos and rhinos. The elephant exhibit will open to the public May 4, and the Zoo is expected to break ground on the hippo exhibit soon after. To help pay for the improvements, the Zoological Society is raising $25 million through its Window to the Wild Capital Campaign.

Hippopotamus Exhibit

The new hippo exhibit will cover 13,000 square feet, more than twice the size of the current exhibit, with a large beach area and underwater viewing.

Back in 2008, representatives from GRAEF and the Milwaukee County Zoo went on a whirlwind tour of zoos, visiting underwater hippo exhibits in San Diego, San Antonio, St. Louis, Tampa Bay and Orlando in a span of four days. They noted what worked and what didn’t in the exhibits, Pitcher says. “There was a lot of attention to viewer experience – the glass, the structure, the building it will be housed in – for example making sure that it’s dark so you’re not getting glares from the lights preventing you from seeing into the water.” Then the real work began of designing an exhibit for Milwaukee, says Erin Dowgwillo, elephant care coordinator and pachyderm keeper. “We worked closely with the engineers, architects and pachyderm staff to try to get the best possible design for our space. There were lots and lots of meetings and blueprint reviews.”

The resulting design dramatically increases the space for hippos both in and out of the water and offers the hippos more choices throughout the day. It includes a beach area three times larger than the current space with different surfaces to give the hippos the choice of where they want to lie. The pool offers varying depths of water, 7 feet at the deepest, with sloped rocks and ramps to give them different resting options. Choice is an important part of animal enrichment, which is the effort to draw out animals’ natural behaviors and meet their physical and psychological needs.

Water filtration technology is constantly improving in sustainability and disinfection, Pitcher says. The system in Milwaukee will use ozone to purify and clarify the water in the indoor and outdoor pools, says Zoo Director Chuck Wikenhauser. The same system is already being used in the new otter exhibit. “It will be a healthier environment for the hippos,” Wikenhauser says.

The system will also save money and be good for the environment. Previously, zookeepers had to empty the outdoor and indoor hippo pools at the end of each day, but the new exhibit will filter and reuse the same water for the entire season, saving 20 million gallons of water a year. Solid waste will be composted. The filtration equipment will be stored in the basement of the former elephant building. “That’s one of the biggest logistical challenges of this project,” Pitcher says.

The result is a much better experience for hippos and visitors, Wikenhauser says. “Visitors will be able to really see the hippos, instead of the tops of their heads.” When completed, the outdoor exhibit will be open approximately April through October, as hippos can’t tolerate the cold. After more than a decade working on the project, Pitcher says he’s excited for families, including his own, to finally see the finished exhibit next year. “When kids see these huge animals up close, underwater, I think it’s just going to be an awesome experience. It’s going to be great for Milwaukee and great for the Zoo.”

YOU CAN HELP THE HIPPOS GET A NEW HOME! The Zoological Society is raising money for the new hippo habitat for its 2019 annual appeal. Visit to learn more and donate.

By Stacy Vogel Davis

This article appeared in the spring 2019 issue of Alive magazine.