Back to Nature
After centuries of focusing on entertainment, zoos are evolving to meet the changing needs of our ecosystem.
It’s fitting to look back and see how far animal institutions have come, and how far they have to go.
By Sean Downey

It’s spring in San Diego, and the polar bears are loving it. Kalluk clamors to his feet and belly flops his 576-pound body into the snow, to the delight of the crowd gathered around the two-acre exhibit shared with Siberian reindeer and Pallas’s cats. Behind him, Tatqiq and Chinook splash around in the Plunge, and Shikari snoozes. All four of the polar bears are completely unaware that they are in a zoo in the Southwest plains of the United States and not their natural habitat in the Arctic tundra.

Just a few years ago, snow would not have been part of the picture at the San Diego Zoo’s polar bear exhibit, but with some ingenuity, research, and technology, the zoo staff has created what Dr. Larry Killmore calls a sensory-rich environment. Despite criticism for having polar bears in one of the warmest parts of the country, Killmore, deputy director of collections of the Zoological Society of San Diego, says the polar bears are doing just fine. In fact, the 130,000 gallons of 55-degree water in the Plunge and drifts of manufactured snow are heaven to the bears, and the enormous sandbox gives Kalluk and his friends a place to dig—or nap—if they want.

As the polar bears play and interact, it’s hard to believe that this species is known for having a hard time adapting to captivity. They often exhibit repetitive behavior, such as pacing back and forth.

Several decades ago, an exhibit housing polar bears would likely have been a concrete setting painted to look like ice and snow, which would have brought criticism from all sides. In 1993, biologist Alison Ames published a study on polar bears in zoos, describing how exhibits that gave the bears authentic enrichment would stimulate the animals to play and socialize. This would be entertaining to the public and would allow handlers and biologists to record more genuine behavior. The research merely hints at how much zoos have improved in so many ways throughout the past few decades.

Specifically, improvements in exhibit design, diagnostics, animal husbandry and enrichment, and overall collection planning have improved significantly throughout the past quarter century, Killmore says. “What has happened in just the past two years alone is incredible.”

Although staunch critics still exist, zoos, overall, have changed for the better, even throughout the past few years. Curators, animal handlers, and zoo advocates point to the increasing use of naturalistic exhibits, where zoos try to recreate animal habitats, often with great success, for the benefit of the animals, the species, and the visitors. The experts contend that conservation of endangered species and educating the public about animal behavior is as much a part of their mission as entertainment.

Critics will point to zoos in peril while supporters will just turn to the numbers: With 135 million people visiting zoos each year, these institutions are sure to be a part of our future.

Although no one can say for sure where or when the first zoo opened, menageries and private collections of animals are a part of our earliest known history. Killmore describes them like Noah’s Arks, housing a dozen or so species on display in a rather small space.

People have been concerned about zoos for centuries. Worldwide, zoos have been rightfully and wrongfully questioned, attacked, prodded, condemned, lauded, martyred, glorified, and exploited for hundreds of years as the public, city officials, and watchdog groups try to determine what’s best for the animals, and if captivity is sanctionable in any form or setting.

Historian Jeffrey Hyson, a professor at Saint Joseph’s University in Philadelphia who is finishing a book on the history of zoos, says it’s difficult to evaluate the history without distinguishing the various types of facilities that keep captive animals. “It’s fair to say, though, that 18th- and 19th-century menageries were often lousy places for animals, and well into the early 20th century you can find distressing reports about how quickly new acquisitions died,” he explains. “There simply wasn’t the kind of professional veterinary knowledge that has become the standard in recent years.”

In the 35 years he’s been in the field, Killmore says the most dramatic change in the science of zoos has been in exhibition creation. “When I came into the field we were entering what you would consider our second generation of exhibit design,” he says. “We’d gone from cages in the traditional zoo environment to open moats.”

According to Killmore, in the past 20 years there’s been a slow evolution in exhibition design toward more naturalistic exhibits. Cement has been replaced with grass, and walls have given way to landscape emersion.

He describes the modern exhibit development process as “pulling the landscape from outside the exhibit to inside, and softening all of those edges.”

Killmore remembers a time before naturalistic exhibits were prominent and says the deference to the animals is now the top priority. Some architects specialize in exhibit creation. “I can remember when we were using architects who did local office building firms to build exhibits, and now we have an entire industry of zoo exhibit architects,” Killmore says. “They are taught the technology that’s involved in designing animal exhibits, which is a lot different than designing office space.” Now architects come to the projects with knowledge on implementing animal enrichment within the infrastructures of the exhibit.

These naturalistic exhibits often feature a variety of species, as opposed to just one type of animal, which is the more traditional method. Killmore credits the new orangutan/siamang exhibit at the San Diego Zoo, called Absolutely Apes. The orangutans, which love to interact with people, are housed with the siamangs, the smaller of the two primates, with an inflatable throat sac the size of their heads.

There is a period of adjustment for the animals, he says, but that’s to be expected. “You have to design the exhibit from the floor looking up to the tops of the trees knowing that you need to provide special environments for these animals,” he explains. “So, if they’re having a bad day or not getting along, they can get away from one another, and it’s worked out very well. The public loves it because they’re only an inch away from the animals and there seems to be no problem between the species.”

However, Hyson says naturalistic exhibits can also have a downside if the funding to provide staffing and equipment is insufficient. “I often worry that the increasing emphasis on flashy, naturalistic exhibits may come at the expense of basic services to the animals and the visitors,” he says.

Killmore believes the technology that goes into caring for the animals, building the exhibits, communicating with field scientists, and educating the public is the real story of the past decade in zoo evolution. While zoos juggle their various roles of conservation, education, and entertainment, the tools at their disposal allow zoos to care for each species with precision.

In terms of the instruments they use to create the exhibits, Killmore says they are often simple but add to the visitors’ experience and the quality of life for the animal. For example, various elements at the Bronx Zoo’s Tiger Mountain exhibit were designed as enrichment items for the animals, thanks to advances in technology and ingenuity. Some of the trees act as pull toys, which is engaging for the tigers and the visitors, and keeps the tigers strong. The rocks are temperature controlled, so, depending on the weather in New York, they can be either warm or cool. When things really heat up in the Bronx, cold water is pumped through tubes beneath the rocks, which keeps the tigers from retreating indoors. This has long been an issue for zoos in the summer when visitor numbers increase. “Kids are out of school and come to see the animals, but they are often asleep or inside to escape the heat,” Killmore says. “The fact is that animals like to sleep, and they don’t like to be hot. They won’t always be active.” But these subtle advances in technology help keep the animals in sight and, in the case of Tiger Mountain, encourage activity. Accommodating species that need to be housed in specific temperatures, for example, is much easier to do with recent advances in heating and cooling, he says. “Some of the heaters just warm the actual living entity that’s in the building. Others warm flesh,” Killmore says. Instead of systems that would simply blow hot or cold air into the exhibit, new heating and cooling systems are often programmed to affect specific areas or the animals themselves. This is more energy efficient and keeps the animal more comfortable, he explains.

Landscaping improvements and technology give zoos the opportunity to offer visitors closer views of the animals and provide vibrant, flourishing exhibits with vegetation and color. “One of the things in particular is an item we call Hot Grass,” Killmore explains. “It looks just like regular grass, but it’s a copper item that we put in front of the more sensitive vegetation. Animals won’t cross that area because it has a pulsating electrical charge in it. It doesn’t hurt the animal; it’s just enough to say, ‘oh, I don't want to be there.’ That way, we can put a lot more vegetation there and make it look a lot nicer.” The Nashville Zoo’s tiger exhibit, which was re-opened after a major renovation in 2001, uses strands of Hot Grass to keep their tigers from entering the moat that separates them from the visitors. Since the electrical wiring is designed to blend in with natural grass it doesn’t take away from zoos’ efforts to make the exhibits imitate the animals’ natural habitats, while allowing zookeepers to maintain control.

Technology that goes into exhibit design is the most apparent improvement to the public, but behind the scenes changes in veterinary diagnostics and treatment have also been on the rise. “We can pinpoint problems quickly and solve them and give the animal a good quality of life,” he says.

Many in the industry share Killmore’s contention that zoos’ greatest achievements have been the improved conditions of the exhibits themselves. Though Hyson would agree, he looks at their efforts in terms of ecology. “The greatest achievement of zoos in the 20th century was the shift from being net consumers of animals to being net producers of them; the vast majority of zoo animals are now captive bred, greatly reducing the strain on wild populations, which have enough problems as it is,” Hyson says.

Model zoos, Hyson says, like Vienna’s Schoenbrunn Tiergarten and Seattle’s Woodland Park facilities, have been working on captive breeding for many years—in fact, Schoenbrunn bred the first elephant born in Europe using artificial insemination.

Captive breeding is still not a perfect science by any means, but Hyson believes the efforts are putting zoos in the position of giving back to the ecosystem.

Killmore believes the most critical issue for zoos, specifically in the United States, is space. Of the 40,000 acres that zoos cover in the United States, 10,000 belong to The Wilds outside Columbus, Ohio. Each zoo, he says, has to determine how to get the funding it needs for increased space and other improvements. There is no single best formula for funding zoos, Hyson says, in large part because zoos exist at the tangled intersection of private and public property. Some zoos, such as San Diego and the Bronx, began with strong private zoological-society support and built their finances largely on donations and earned income. Others, like Saint Louis and Lincoln Park, opened as municipal institutions and continue to draw substantial amounts of their expenses and capital funds from local taxpayers.

“Unlike amusement parks and theme parks, zoos will always have a publicness of mission and identity that allows them to appeal to government leaders for support,” Hyson offers. “At the same time, the days of the free municipal zoo—once the standard management model—are long gone, thanks to urban fiscal crises. And so the challenge continues.”