Zoo designers already use architectural elements to try to keep children from going over railings into exhibits, but the breach at the Cincinnati Zoo's gorilla enclosure over the weekend has prompted experts to look at whether changes are needed.
Today's designs leave 4 feet between a railing and a moat so that anyone falling from the railing will not land in the moat. Railings themselves sometimes have uneven pickets to make it difficult for anyone to sit on top of them.
"That 4-foot space, that’s come about over time because there have been so many incidents of parents setting a child on the railing," said Patrick Janikowski, a principal of PJA Architects and Landscape Architects, a Seattle-based firm specializing in zoo design.
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"I don't want to say it’s designed for stupidity, but that's the reason that that is designed that way, as a secondary precaution against falling into the moat," he said.
The latest tragedy, in which a 17-year-old, 450-pound western lowland gorilla named Harambe was killed after a boy got into its enclosure, has driven the Cincinnati Zoo and zoo designers to consider changes in animal exhibits.
"Every time something likes this happens, there's a re-evaluation and a re-look to make sure each facility is up to speed," said Nevin Lash of Ursa International, an Atlanta-based design company.
"We're always trying to keep it exciting but safe," he said.
The 3-year-old boy climbed over a fence and fell more than 10 feet into the moat surrounding the gorillas’ enclosure over the weekend, NBC News reported. Harambe was shot after he grabbed the child, a decision zoo officials are defending in the face of outrage from animal rights groups and others. Zoo officials said the endangered gorilla was so large it could have hurt the child even without intending to.
The Cincinnati Zoo has insisted that the Gorilla World exhibit, the first "bar-less" outdoor gorilla habitat in the country when it opened in 1978, is safe. The zoo's director, Thane Maynard, told The Associated Press the breach was the first.
The Cincinnati enclosure is now the industry standard, its open design common in zoos across the country, with exhibits protected by a combination of glass, netting and moats, designers say.
For example, Zoo Atlanta, which has the nation's largest gorilla collection, has several outdoor viewing spots designed to give visitors the feeling of being close though they are separated by a series of safety barriers, the AP found.
The Smithsonian's National Zoo in Washington has an indoor area with glass walls and an outdoor habitat surrounded by barriers made of glass panes, metal and metal frames filled in with mesh. Metal railings and large planters also stand between the viewing area.
But gorillas at the Columbus Zoo are in two enclosed areas behind glass and mesh. The approach is an exception to the open enclosure in Cincinnati, a spokeswoman, Patty Peters, told the AP.
George Houthoff, the CEO and co-owner of Houthoff Zoo Design in Rotterdam, in the Netherlands, urged zoos to evaluate the safety of their exhibits through the eyes of a child.
"Small kids just like to climb," he said. "Sometimes barriers can be taken in seconds."
Zoos could inspect each other's exhibits for safety, he said. Zoo directors should ask their staff members whether they think an exhibit is unsafe. Have they ever seen a near miss? Use the experience of the zookeepers, he said.
Even relatively peaceful species can turn aggressive when their territory is invaded suddenly, he warned, not just big cats or crocodiles. Think about the risks also of falling or drowning, he said.
"Even if nothing happens for years and years, an exhibit can still be unsafe, especially for small children," he said.
PJA Architects designs railings with vertical pickets of different lengths so parents cannot set their children on the top railing and adults cannot sit on them. Still a child likely could climb over it, Janikowski said.
"If they can grab the pickets and pull themselves up, if it's an energetic child," he said. "I would think that because they're vertical, they can't get a foothold anywhere except at the bottom rail. You can still get over it but I think it's a lot of effort. That's why we use it."
Janikowski said that the firm would review the design but doubted it would be changed.
"We think our railings have been tested over time," he said.
This was not the first time a child has gotten into an exhibit. A 5-year-old fell into a gorilla enclosure at the Jersey Zoo in the United Kingdom 30 years ago, knocking himself unconscious. A male gorilla, Jambo, stroked his back until zoo keepers were able to get to the boy.
Ten years later, another 3-year-old boy fell into the gorilla enclosure at the Brookfield Zoo near Chicago. That time a female gorilla, Binti Jua, picked the child up and carried him to safety.
A 2-year-old boy fell into a cheetah exhibit at the Cleveland Metroparks Zoo in April 2015 after his mother allegedly dangled him over a railing. The parents rescued the child.
And another 2-year-old was killed by African dogs after, zoo officials charged, his mother lifted him up onto a 4-foot-tall wooden railing to get a better view. He fell into the exhibit and was attacked. The parents sued the zoo and later settled.
The zoos are inspected regularly by the U.S. Department of Agriculture and the Association of Zoos and Aquariums — on average once a year by the Department of Agriculture, though more frequently if there is a complaint, and every five years by the association for accreditation.
The federal Animal Welfare Act says zoos must have barriers in place between enclosures for gorillas and other primates and the public, but the specifics are performance-based, said a spokeswoman for the U.S. Department of Agriculture, Tanya Espinosa.
"That means that they are deemed to be adequate if they work, and the U.S. Department of Agriculture, which enforces the Animal Welfare Act, has broad discretion into how to administer them," she said.
The Cincinnati Zoo has been accredited by the Association of Zoos and Aquariums without interruption since 1978, most recently in 2014, said a spokesman, Rob Vernon. Its standards are also performance-based, but if a state or municipality has regulations related to exhibiting animals, those also must be met, he said.
Its Accreditation Commission will first consider whatever changes the Cincinnati Zoo makes before deciding whether more needs to be done, he said. He said he did not know of an instance where a zoo made no changes after an accident.
The enclosure should now be looked at through "the lens of a 3-year-old," he said.
Designers rely on the International Building Code, which specifies railing heights depending on the drop on the other side and other requirements. As zoos have evolved from cages for the animals, the animals have gotten healthier and stronger, Janikowski said. Enclosures have gotten larger, moats larger and heights of railings higher, he said.
Lash, with Atlanta-based Ursa International, said that some zoos were moving toward glass-enclosed viewing areas, which are extremely safe.
"But we also like to have the big open views," he said. "You’re standing at the same level or even lower than the animals are and that requires these moats. And they’re very popular in design as long as it’s all safe. We work to make that happen because no one wants what happened the other day."