The Case for Zoos: They Just Might Save the Endangered Pygmy Hippo
Most people have never heard of the pygmy hippo, much less seen one. Until 1844, even scientists did not recognize the existence of this species—a miniaturized, snubbier-nosed (and considerably cuter) 400-pound version of the 3,300-pound common hippo. But pygmy hippos are rapidly disappearing from their West African habitat—and the culprits are entirely familiar.
“Large areas of the original forest habitat, especially in Côte d’Ivoire, have been destroyed or degraded by commercial plantations of oil palm and other products, shifting cultivation, mining and logging, and hunting for bush meat,” reports the International Union for Conservation of Nature.
The IUCN Red List categorizes the species as endangered, with roughly 3,000 adult individuals estimated to survive in the wild. Their shrinking and fragmented habitat occurs in just four countries—Liberia, Cote D’Ivoire, Sierra Leone, and Guinea—and all are prone to political turmoil, corruption, hit-and-run commercial exploitation, and outbreaks of Ebola and other epidemic diseases. A separate subspecies that lived until recently in Nigeria is now apparently extinct.
How to keep the entire pygmy hippo species from suffering the same fate? It depends on both improved protection for their remaining habitat in the wild and better care of the 367 pygmy hippos in zoos, according to Gabriella Flacke, a wildlife veterinarian and doctoral candidate at the University of Western Australia. But understanding how they live and what they need is extraordinarily difficult. Whereas common hippos are widely distributed, highly visible, and also among the most dangerous large animals in Africa, hardly anyone ever sees a pygmy hippo in the wild.
Pygmy hippos are shy, solitary, and nocturnal, living mainly in forests and swamps. In 2013, Flacke worked in Cote D’Ivoire’s Tai National Park, the largest surviving tropical forest in their home range. But even her collaborators there, Ivoirian researchers who have studied the species for decades, had seen pygmy hippos only once or twice. “You make a lot of noise moving through the forest,” said Flacke, “and by the time you get where the pygmy hippo was, it’s a mile away.“
She had better luck studying footprints and dung, which the pygmy hippo scatters in its wake with a rapid, propeller-like motion of its tail. In addition to the samples collected from the wild, she’s now also analyzing 3,500 frozen dung samples (she calls them “hippoopsicles”) from pygmy hippos in zoos. Her ambition is to develop standard methods for remotely monitoring levels of essential hormones such as cortisol, testosterone, estrogen, and progesterone. (Remote methods are essential, even in zoos, because of the “difficulty of handling a large, dangerous, and sometimes disagreeable pachyderm,” Flacke said.)
Given that zoos have been keeping pygmy hippos in captivity since 1912 with what seems to be considerable success, it is remarkable how little science really knows about them. For instance, genetic analysis only recently revealed that pygmy and common hippos should be classed not with the suids (or pigs) but with whales and other cetaceans.
Camera traps in Tai National Park also revealed that pygmy hippos in the wild are far more slender and sleek than their zoo counterparts, which often weigh in at 600 pounds. Writing in the journal Der Zoologische Garten, Flacke and her coauthors argue that zoos misunderstand the dietary needs of these animals and routinely overfeed them. That can have unexpected consequences, beyond obvious issues such as arthritis and foot problems. Zoos have long puzzled over why pygmy hippos routinely produce far more female than male offspring, but a skewed sex ratio may just be an evolved response to favorable feeding conditions.
Zoos also routinely house pygmy hippos in groups, though Flacke and her coauthors write that this practice has at times “resulted in severe injuries and even deaths.” Pygmy hippos are solitary by nature, and even if they sometimes get along in communal circumstances, it may inhibit their reproductive physiology and behavior.
In an interview, Flacke said she does not intend any of this as an attack on zoos but as part of the continual process of improving the care they provide. “A lot of people really hate zoos, and the negative argument against zoos is that they are often like a prison,” she said. But the proposal to simply open the cage doors is just naive, she believes. “They say we should just put all the tigers back in India and all the orangutans back in Sumatra. But they aren’t going to make it. They were born and raised in captivity, and they don’t have the skill to find food and avoid humans. If it’s a dangerous carnivore, it’s going to go and seek people and say, ‘Oh, you’re bringing me my steak.’ ”
Instead, said Flacke, zoos are essential to preserving a species in a rapidly changing world. Like many other natural areas, Tai National Park is under constant threat from gold miners, bushmeat hunters, loggers, and refugees from chaos in neighboring regions. The World Wildlife Fund, which helped instigate the original designation of the Tai Forest as a national park in 1972, continues to provide support for park patrols and other conservation work by the Ivoirian authorities. That work is essential, Flacke said: “If we someday run out of places to put these animals, we’ve sort of screwed ourselves.”
Zoos now sustain about 10 percent of the total pygmy hippo population, and they are essential too. They provide what Flacke called “a safety net population” in case the species vanishes from the wild. They can also be valuable in keeping their wild counterparts healthy—for instance, potentially providing genetic diversity to fragmented wild populations.
It’s easy and emotionally gratifying to attack zoos. The harder job is to help make them work better, not just on behalf of pygmy hippos but for an entire Noah’s ark of threatened species.