Hippos Are in Trouble. Will 'Endangered' Status Save Them?

Adam Welz

This story originally appeared on Yale Environment 360 and is part of the Climate Desk collaboration.

Thanks to years of campaigning by wildlife conservation groups, it's widely known that Africa's elephants and rhinos are threatened by the trade in their valuable tusks and horns. Laws and regulations have been tightened, and in many countries it's now difficult, if not impossible, to legally sell elephant and rhino products.

Less well known is that Africa's other large pachyderm, the common hippopotamus, is also threatened in many parts of the continent, and that thousands of hippo products, including leather, skulls, and teeth, are legally bought and sold around the world every year.

A small consortium of US animal welfare and conservation groups is now trying to change this, pressing the US government to increase legal protections for the common hippopotamus under the Endangered Species Act.

Africa has two species of hippo: the endangered pygmy hippopotamus, found in a small part of West Africa, and the larger common hippopotamus, found across large swathes of sub-Saharan Africa. But despite its name, the common hippo isn't common throughout its native range. It has been extirpated from at least four countries, and its populations are small and declining in many more. In some countries where the species was recently abundant, only tens or a few hundred individuals are left.

On February 15, World Hippo Day, the Humane Society of the United States, the Humane Society Legislative Fund, the Humane Society International, and the Center for Biological Diversity announced that they planned to sue the US Fish and Wildlife Service in an attempt to force the agency to consider listing the common hippo under the Endangered Species Act (ESA). "As the top global importer of hippo [parts], the United States government can no longer ignore its responsibility and the critical role it can play in curbing legal trade," said Adam Peyman of the Humane Society International (HSI). Listing the species as endangered, the organizations said, "would place near-total restrictions on most imports and sales of hippo specimens and provide awareness and funding to achieve the ESA's conservation goals."

The tactic worked. The Fish and Wildlife Service is now soliciting comments before deciding whether to start the listing process. Designating the hippo "endangered"--it is already listed as "vulnerable" by the International Union for Conservation of Nature--would not completely halt the importation of hunting trophies, said Tanya Sanerib, international legal director of the Center for Biological Diversity. But it would require the agency to ensure that the hunting "enhances the survival of the species." Prospective importers would have to prove that the hippo hunting had conservation benefits, a difficult and time-consuming task. Listing a foreign species under the ESA would also allow the US government to dedicate funds to its conservation.

Many hippo experts welcomed the new attention on the animal, which has long been neglected in research and conservation circles. But they say that the trade in hippo parts is hardly the animal's biggest threat and that banning this trade will likely have no conservation benefit. Unless the ESA listing spurs consideration of far more serious threats to hippos, these experts say, the move will likely be meaningless. And it may even cause harm.

Scott Gilbertson

Beth Simone Noveck

Amanda Hoover

Brenda Stolyar

Hippos are curvaceous vegetarians that spend most of the day lazing around in water with just their large nostrils; tiny eyes; and small, swiveling ears projecting above the surface. Because they are vulnerable to sunburn, they must keep their skin hydrated. Although they inspire motherly, comical, or friendly characters in children's books and TV shows, common hippos are dangerous beasts. The species ranks, with crocodiles and venomous snakes, near the top of the list of Africa's most deadly animals, says Simon Pooley, an expert on human-wildlife conflict in Southern Africa.

Among land mammals, the common hippo ranks in size just behind the two African elephant species and the white rhinoceros. A large male can weigh roughly 4,500 pounds. Hippo jaws can open to almost 180 degrees, exposing fearsome front teeth, including sharp canines that project up to 20 inches from their gums. They can be highly territorial, often attacking and sinking small boats that approach too closely. At night, hippos leave the water to graze on land, where they sometimes encounter people. Given that panicked hippos can gallop at 19 miles per hour, these meetings can end fatally for humans.

Despite their size and strength, hippos are easily hunted. They're simple to find and to shoot in the water. And if a hunter doesn't have a gun, a piece of nail-spiked wood or a wire snare placed on a hippo's habitual waterside trail will cut open its feet, triggering a fatal infection.

Thousands of hippos are killed annually, mostly by Africans who live near them but also by visiting sport shooters. Hunters often take specific parts from carcasses, including teeth, which make a low-quality elephant ivory substitute; skin, which can become marketable leather; and bones, a curio for collectors. Many of these parts are sold to intermediaries and make their way into international markets.

In a joint press release, the group advocating for listing the hippo as endangered stated that between 2009 and 2018, parts from at least 3,081 hippos had been legally imported into the US. Hippo experts don't dispute that number, but they don't believe it indicates that significant numbers of hippos are dying for the trade in their parts. The animals, they say, are almost always killed for other reasons.

In many African countries, hippos and people increasingly compete for fertile land and fresh water. "Hippos require very much the same resources as we do," says Rebecca Lewison of San Diego State University, who cochairs the International Union for Conservation of Nature's Hippo Specialist Group. Irrigation schemes and climate-change-induced droughts dry up water bodies, and new dams flood hippo habitat. Every day people carve out new fields and orchards alongside hippo-filled rivers and lakes, so the animals increasingly feed on human crops and come into conflict with ever more people. Moreover, their flesh is rich and tasty, and a single animal can yield more than a thousand pounds of meat--enough to feed a whole community or generate large profits at a local market.

Scott Gilbertson

Beth Simone Noveck

Amanda Hoover

Brenda Stolyar

"My view is that the US trade [in hippo parts] is largely a byproduct of other reasons for killing," says Crawford Allan, a wildlife trade expert with the World Wildlife Fund. In Africa, he says, "nobody wastes anything. So if you kill an animal because it's a danger to your community, then you eat the meat, you sell the skin, you sell the teeth, you sell the skull to taxidermy collectors." Hippo parts like teeth and skin, he says, are not worth enough to local hunters to provide an important reason for killing them.

Other experts echo this opinion. Lewison cites the example of Virunga National Park in the Democratic Republic of the Congo, where the hippo population declined from almost 30,000 in the mid-1970s to fewer than 1,000 by 2005. The animals were killed during civil unrest and war "when everyone was starving. And they ate them."

Lewison acknowledges that hippo parts are sometimes found in seizures of trafficked wildlife products, but she says that they form a tiny part of the illegal wildlife trade, which is sustained by far more valuable products, like elephant ivory and rhino horn.

An analysis of official trade numbers by HSI and its collaborators showed that, of the hippo products imported to the US between 2008 and 2019, 2,074 were hunting trophies. (Other nations legally imported roughly 2,000 more hippo trophies during the same period). However, a trade database compiled by the Convention on International Trade in Endangered Species of Wild Fauna and Flora reveals that virtually all the trophies and other hippo parts tabulated by the HSI came from countries with large, apparently well-managed hippo populations. Neither HSI nor the Center for Biological Diversity provided any data that linked hunting trophies or other legally traded parts to hippo declines.

Paul Scholte, an Ethiopia-based member of the Hippo Specialist Group, says that regulated trophy hunting can have conservation benefits. With local colleagues, he conducted and published surveys of hippo populations in northern Cameroon that show declines in government-run conservation areas and either stable or increasing populations in areas leased by private trophy-hunting outfitters.

"The factor that explains if a population of hippo is stable or not is a year-round presence of protection--of rangers or scouts," Scholte says, explaining that government rangers do not patrol during much of the rainy season, when moving around is difficult. Trophy-hunting companies, however, have the funding and motivation to continuously protect their concession areas from the poachers and illegal gold miners who kill hippos in that region.

Hippo experts say the focus on the parts trade is a distraction from more important issues and that it escalates friction between African countries. They point out that southern and eastern African countries--which have larger and better-managed conservation areas--generally host more secure hippo populations than do countries in Central and West Africa, where many populations are on the brink of extirpation.

These varying circumstances lead to different views on conservation policy: West and Central African authorities generally favor wildlife trade bans, which they believe would discourage poaching of their extremely vulnerable populations, while most countries in southern Africa and some in East Africa argue that their populations are large enough to sustain hunting and commercial trade, which fund wildlife conservation.

Scott Gilbertson

Beth Simone Noveck

Amanda Hoover

Brenda Stolyar

Experts warn that imposing a one-size-fits-all "solution"--such as an ESA listing--on the African continent could create serious problems. Allan, of the World Wildlife Fund, says "it sets up a division that isn't healthy" between countries that want to make consumptive use of their wildlife and those that don't. Banning imports of hippo products from some countries while allowing them from others, he adds, would create an "enforcement nightmare" because parts from different regions are essentially indistinguishable. The legal trade could thus be used to launder poached items.

Rebecca Lewison says that hippos have been understudied for decades. Even basic hippo population estimates are years out of date, in part due to pandemic-related delays. The Hippo Specialist Group's latest effort to gather population numbers is only getting underway now, and it's possible that it will discover some populations are not as healthy as they used to be.

Hippo declines would have knock-on effects for other species too. Hippos are important shapers of aquatic ecosystems: As they move around, they keep river channels open, and because they are so large, they can consume tough, tall species of grasses, creating "grazing lawns" of short, palatable grasses that support other animals.

Recent research by Scholte shows that a hippo population collapse in the Ivory Coast's Comoe National Park during a recent civil war has led to a massive, sustained reduction in numbers of the Buffon's kob, a type of antelope. With no hippos to maintain them, the park's grazing lawns have been overtaken by dense thickets of unpalatable tall grasses, and the kob population has dropped from more than 50,000 to fewer than 3,000.

Lewison says that more money and expertise are urgently needed for hippo research and protection. Robust surveys are required to identify the populations most at risk, she says. New methods to reduce human-hippo conflict must be developed. Hippo habitat conservation needs better funding. And populations at risk of poaching must be protected.

The push to list hippos as endangered, says Lewison, "may be the first step toward really engaging a wider audience and global conservation efforts. But if it succeeds, it is only a small beginning."