In the future, zoos will host struggling native animals, rather than keeping megafauna captive.

Zoos Should Set the Tigers and Gorillas Free, and Save These Critters Instead

Zoos Should Set the Tigers and Gorillas Free, and Save These Critters Instead

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The state of the universe.
June 27 2016 7:28 AM

Lions and Tigers Don’t Belong in Zoos. But Some Animals Do.

The zoos of the future should host struggling local animals, not keep megafauna captive.

Lowland gorilla
Shinda, a Western lowland gorilla, holds her newborn as they rest at the Prague Zoo in April.

Michal Cizek/AFP/Getty Images

Black-footed ferrets once thrived on the North American prairie, with an estimated 5 million animals occupying some 100 million acres of land from Montana to New Mexico. In the 19th century, though, America’s expansion west devastated the species. Prairie was converted into farmland and settlements. Prairie dogs, which the ferrets relied on for both food and shelter (using the dogs’ burrows for dens), were eradicated to keep them from competing with livestock for grass. Squeezed out of their habitat and deprived of their main food source, the ferrets declined and then disappeared. In 1979, the last captive ferret died, and the species was presumed extinct.

Then, two years later, a Wyoming rancher’s dog brought home a dead ferret to its master, leading to the discovery of a small remnant population—100 or so ferrets that had, against all odds, survived—near the town of Meeteetse. When disease threatened this group and their numbers started to decline, various stakeholders came together to decide that the remaining 18 animals should be brought into captivity and placed in the care of the U.S. Fish and Wildlife Service. They were housed by several zoos accredited by the Association of Zoos and Aquariums, which today include the Smithsonian Conservation Biology Institute, the Louisville Zoological Garden, the Toronto Zoo, the Cheyenne Mountain Zoo and the Phoenix Zoo. The organizations involved created the Black-footed Ferret Species Survival Plan, which, in the past 35 years, has bred more than 8,000 ferrets from those original 18. They’ve released around half of those to nearly two dozen sites in their former range. Today, some 500 black-footed ferrets live in the wild. (Another 250 are still at breeding centers.)


After a 4-year-old child accidentally fell into a gorilla enclosure at the Cincinnati Zoo and forced the staff to euthanize an adult gorilla for the child’s protection in May, animal lovers rallied on behalf of Harambe, the gorilla, and against the practice of zoos in general. If the black-footed ferret had a Twitter account and a say in all this, I’m pretty sure it might have a different take. It is thanks to zoos’ efforts that the ferret survived at all. This success story offers a different alternative for what zoos could become. Rather than housing exotic animals that require habitat that far exceed what a zoo can reasonably offer, zoos should be converted into conservation centers equipped to help local struggling species find their footing again.

Pre–20th century zoos were just menageries full of concrete and cages where people could go and gawk at weird wildlife. But midcentury—amid declines in wildlife populations and pressure to change from both internal and external forces—zoos began shifting to a conservation-focused mission, thinking of themselves as Noah’s arks for species in danger. Beyond hosting reserve populations, zoos also started participating in conservation programs both by researching their own animals, and funding research and conservation in the wild. Educating visitors about biodiversity and conservation became a central goal, and cages were converted to larger, more open exhibits. Within a few decades, and with the World Association of Zoos and Aquariums’ explicit urging, most modern zoos followed along. “Captivity for Conservation” became their slogan, environmental philosopher Jozef Keulartz writes, and many zoos even began reintroducing some of their animals to the wild rather than having them live out their days in captivity.

That shift in thinking brought more programs like the one that saved the black-footed ferret. For example, the last 27 California condors, threatened by lead poisoning and habitat loss, were captured in 1987 and sent to the Los Angeles and San Diego zoos for breeding and reintroduction. These enormous birds were first reintroduced to the wild in 1991. As of their last census, the condor’s wild population exceeds 200 birds in the U.S. and Mexico with more than 150 condors in six zoos. Another success story is the Wyoming toad, which was considered extinct in the 1980s, just 40 years after it was discovered. But zoo-based captive breeding, using a small rediscovered population, has led to tens of thousands of tadpoles and toadlets being released in the wild and re-establishing wild breeding populations.

All of this has an even older historical precedent which, while less premeditated, was certainly still effective: In the early 1900s, when there were more bison in captivity than in the wild, the Bronx Zoo provided Teddy Roosevelt’s American Bison Society with 15 bison and shipped them by rail to Oklahoma to establish a herd at a wildlife refuge. This herd helped bring our national mammal back from the brink of extinction.


These and other animals owe their existence to the reintroduction programs run by zoos around the country. Cases like these, where zoos breed and re-establish species in the wild close to home, have been their greatest conservation successes. The impact this work has on the wild is intangible, but it is certainly better than the estimated 1–3 percent of most zoo budgets devoted to conservation efforts or education programs. Studies that have tried to measure the effects of education in zoos provide a mixed bag of evidence, with many finding that people take in information about conservation at the zoo but don’t leave ready or able to do anything about it. Even the World Association of Zoos and Aquariums’ own research reports that zoo and aquarium visits increase peoples’ understanding of biodiversity, but that their understanding is limited—that is, they know what biodiversity is but not why it matters. As we stand on the brink of another biodiversity crisis, zoos should redirect their efforts from education that doesn’t seem to be making much of a difference to programs that could.

To be clear, reintroductions are not a panacea: They’re incredibly hard and rarely successful. A 1995 study found only 11 percent of reintroduction projects using captive-bred animals led to a self-sustaining wild population. They’re also expensive—the condor recovery program has spent more than $40 million since it started—and require the space and resources for maintaining a large enough group of “founder” animals to ensure genetic diversity and limit inbreeding.

But it’s also developing science and, in many ways, one of the best chances we’ve got. Reviews of case studies from recent years found that more than half of reintroductions are successful. Still, the problems and mixed results of reintroduction programs have led some conservation scientists to write them, and the ark model of the zoo, off. Steven L. Monfort, director and chief scientist of the Smithsonian Conservation Biology Institute, warned that the ark was sinking, while Keulartz called it “irretrievably shipwrecked.” Meanwhile, conservationists Mark Stanley Price and John Fa say reintroduction has been a shooting star instead of a guiding light, “providing an eye-catching attraction but not long-term illumination for conservation.”

The problems that wildlife faces—habitat loss, poaching, disease, climate change—aren’t going to go away and will likely just get worse. The ark model isn’t going to save all species; in fact, a zoo should be less of an ark for all animals and more of a lifeboat for a select few, a smaller, locally-focused institution whose goal is returning wildlife to the wild. Zoos need to realize their limitations and stop trying to save every species. We need to accept that not all threatened species can be kept in “insurance” populations in zoos, and that non-threatened species shouldn’t be kept in zoos at all. Zoos should specialize in species that are the best candidates for reintroduction. To better prioritize, and to have a better chance of success, each zoo should focus on its native flora and fauna as closely as possible.


Not only would many zoo collections get smaller but in most places, so would the animals in them. Reintroductions only work with species that maintain the skills and temperaments they need to survive in the wild after being raised in captivity; when there are enough animals being reintroduced; when there’s suitable habitat for them to be reintroduced to; and when the causes of their declines have been identified and brought under control. That would mostly leave zoos with less-charismatic megafauna and more small mammals, reptiles and birds, amphibians and invertebrates. For one thing, these animals are certainly in need of help: Amphibians are the most threatened taxonomic group, according to the International Union for the Conservation of Nature.

In North America, small- and medium-size animals are heavily represented among the species listed under the Endangered Species Act. Smaller animals also generally have higher birth rates, smaller habitat ranges, and less complex social systems, making it easier to breed them in sufficient numbers, secure habitat and re-establish them in the wild. Focusing on smaller species could also help solve some of the limitations of captive breeding and reintroductions, like space and cost, since they require less space, are less expensive to keep, and come with fewer welfare problems in captivity.

Reintroduction-focused zoos would also think locally and, like with the black-footed ferret and California condor, put their efforts into threatened species from the surrounding regions that can be reintroduced nearby. This would not only limit the distance of costly animal transfers from zoos to release sites, and give zoo scientists the opportunity to study an animal’s wild habitat and ecology (upping the chances of successful reintroduction), it could also improve zoos’ education and outreach efforts. Local species and regional problems specific to, say, Nebraska, are more relevant to zoo visitors in Nebraska than the plight of an animal in some far-flung corner of the world. Learning about them can, hopefully, encourage local involvement and action to protect habitat.

It would also make your local zoo different from any other one: Zoos around the country (and the world) could differentiate themselves from each other with species unique to the regions they call home. You can already see aspects of this approach at the Arizona–Sonora Desert Museum near Tucson. Its zoo, aquarium, natural history museum, botanical garden, and art gallery are focused entirely on the surrounding region’s natural history, and house only native plants and animals. That means no hippos or pandas; instead, there are Merriam’s turkeys, striped skunks, and lots of bugs and other invertebrates (which outnumber the mammals 840 to 106). It may not seem as initially exciting as today’s zoos, but it certainly is more ethical.

Who knows if people would still pay the money they currently fork over for this new kind of zoo. Regardless, with a refocused mission, zoos could find funding from other means. While this is a bit of a thought experiment, if the public opinion that surfaced following Harambe’s death is any indication, there should be support for at least considering this as a way to shift zoos and their missions. Humans tend to forget that, in the wild, health is measured on a population scale—not on an individual scale. Converting zoos to actually support animals this way would be the best chance they’ve got at staying relevant, not to mention being a good raft for the many animals that so desperately need a lifeboat.

Matt Soniak is a freelance journalist who writes about biology, conservation, and history. He lives in Philadelphia. Follow him on Twitter.