CINCINNATI — There's good news for those anxiously awaiting the end of the Cincinnati Zoo and Botanical Garden’s 20-year hippo hiatus.
The $8 million, newly constructed Hippo Cove will officially open Thursday, featuring a 70,000-gallon pool complete with a transparent wall for underwater viewing. The exhibit also features a state-of-the-art filtration system to keep the new hippo pair’s water sparkling clean and clear.
“Everyone is really excited about it,” said Cincinnati Zoo Director Thane Maynard. “Over the years, the No. 1 animal I’ve been asked to bring back is the hippo.
The zoo’s newest residents came courtesy of two separate locations in Missouri; 17-year-old female, Bibi from the St. Louis Zoo , and 34-year-old male, Henry from the Dickerson Park Zoo . Introducing animals can always be unpredictable, Maynard explained, as people know when they introduce new dog or cat to other animals at home. Fortunately, he said the two seem to be getting on famously since gradually getting to know each other in side-by-side pools.
“They became very aware of each other and very interested in each other, so we put them out and they’ve been doing great,” he said. “They seem to really like each other. Many times when I go down to the exhibit I’ll see them lounging right next to and on top of each other near the waterfall.”
Ultimately, the zoo's hope is to see baby hippos in the not too distant future, Maynard said, as they’ve been given the OK by the Association of Zoos and Aquariums (AZA) to breed the pair.
“They’re a gregarious species, they live in big groups, so when they have a baby we can have a third one in there,” he said. “They like to be near other hippos.”
Opening the exhibit in July is perfect timing for the warm-weather-loving mammals, Maynard said. The Nile hippos secrete oil from their glands that acts as a sunscreen, he said, allowing them to bask in high temps and sun. But even though they fare well in heat, he said they also tolerate cold extremely well, with 4,000 pounds of body weight.
“They won’t just be out six months of the year, they’ll probably be out 10 months,” Maynard said. “They’re great big animals, so it takes a lot to cool them off.”
As the species spends the majority of its time in the water, Maynard explained one of the key components of the new exhibit is the filtration system. On average, hippos produce 22 pounds of waste per day and always while in the water. As a result, he said keeping the pool clean and clear can be the ultimate challenge. Due to the complexity of the task, he said only a handful of zoos across the country feature hippo exhibits with clear pools. He compared their new system to a swimming pool filtration system on steroids.
“It’s an interesting exhibit, it was $8 million – one million was the swimming pool with the glass and $7 million was the filtration system and that sounds crazy, but it’s really true,” he said. “It’s fun for visitors to see them through that clear wall, but it’s not as easy as it sounds.”
Head keeper of aquatics David Wardlow said an experienced outside engineering firm specializing in interactive filtration designed the system. He said keepers can monitor performance virtually from any location using an iPad or smartphone. To keep the pool clear, he said the system pumps and filters 1,800 gallons per minute with a turnover rate of every 37 minutes.
“The idea is if there’s a fecal event — which there will be — the water can flow from one end to the other and clear that up relatively quickly,” Wardlow said.
The design also features a rake of sorts that collects some of the “processed hay” prior to filtering. He said water then goes through straining, oxygenation and disinfecting before being recycled. With the additional filtration system and water exhibit, he said they’ve added full-time water specialist Rebecca Sprague to their staff to monitor conditions on all exhibits. The water source for the pool will come solely from captured rain water, staying true to the zoo’s mission of sustainability.
“We have dramatically dropped our water usage,” Wardlow said. “If my figures are correct, in 2005 we averaged around 240 million gallons of water use a year and last year we came in under 60 million gallons. “
After viewing the hippos, Wardlow recommended visitors check out the massive filtration system for themselves through a window located just behind the exhibit.
“Water is a unique substance that we have on this planet and a lot of people don’t think about it, but all the water that’s here now has always been here and we recycle it all the time," Wardlow said. "So ultimately we’d like to send it out of here in the best shape as possible.”
Hippo Cove puts the finishing touches on the zoo’s Africa Exhibit , which Maynard explained cost $34 million and took nine years to complete. Unlike other zoos that levy tax payer dollars for projects, Maynard explained funding for their new exhibits comes solely from private and corporate donations. He said the fundraising process may have taken a little longer, but the results were well worth the wait.
“So we were able to grow and build a big African exhibit,” he said. “It started with giraffes, then cheetahs and then lions, so the sort of cherry on top of the whole thing is adding hippos.”