Reports of baby pygmy hippos in Thailand and in Richmond, Virginia, have garnered much attention for their respective zoos, attracting many visitors. These cuties look like they are lovable little creatures whose only goal in life it to make you smile. Visitors to areas where normal-size hippos live, however, are cautioned to beware of hippopotamuses, the most dangerous animal in Africa.

Turns out hippos can outrun us and outswim us and do not much care for the presence of us or any other animal. Every safari guide I talked with confirmed that anyone venturing between the water and where a hippo was grazing on land should be sure their final arrangements had been made. This is not to say that hippos have a grudge against humans. But except for the pygmy species, that adorable baby hippo with its cute ears will grow up in the wild to weigh more than 2 tons. And it can kill a human by trampling, biting or drowning. Although no one has indisputable statistics, hippopotamuses in Africa reportedly kill as many as 500 people annually—more than any other wild mammal.

Interesting in their own right, these enormous creatures (whose closest relatives evolutionarily are whales, not pigs) also have a connection to illegal drugs from another continent. Enter Pablo Escobar from Medellin, Colombia. He once ran a worldwide drug cartel, raking in millions of dollars in the 1980s and 1990s to become one of the wealthiest men in the world. When you are super wealthy you can buy what you want. If you want four pet hippopotamuses (and who wouldn’t?), no problem. Pablo created a private zoo in South America for his pets from Africa, which included such misplaced wildlife as elephants, giraffes and ostriches. No doubt their arrival made the hippos feel more at home.

For the first decade, all the animals at his estate were fine. They had food and proper care. By the time Pablo Escobar was shot and killed in 1993, his quartet of hippos had lived there a dozen years. Colombian authorities rehomed most of the animals at other facilities, but no one wanted to start a hippopotamus zoo. So authorities let the small herd of now ponderous adults roam into the nearby Magdalena River. Having increased more than tenfold in numbers, they are now the largest collection of hippopotamuses outside Africa.

Environmental issues centered around nonnative species often get messy. Some tourism companies appreciate having hippos in the river as an ecosystem novelty. Some wildlife managers want to eradicate them to preserve the native fauna. Animal rights advocates want to protect them as individuals. The Magdalena River is rich in native biodiversity, including manatees, American crocodiles and parakeets. One seriously endangered species, the Magdalena River turtle, is estimated to have been reduced to less than 20 percent of its original population size, not because of hippopotamuses in the neighborhood but because of human exploitation. Like many declining wildlife species, the turtle and its eggs are taken for food by locals, even though it is on an endangered species list.       

 Controversies swirl about how to handle feral hippos. Should they be culled, as their population is likely to grow into the hundreds over the next few years? Will they be a plus for the Magdalena River turtle or another minus? On the positive side of the ledger, hippos might very well create new wetland habitats that favor turtles and other native species. And the presence of hippos in and around the river could indirectly have a positive effect for many wild animals by discouraging poachers, who might be less likely to ply their trade in the river or along its shorelines if an antisocial hippo is patrolling the area. Environmental issues often generate highly polarized positions with no easy resolutions. The situation with “the most dangerous animal in South America” will prove to be one of them, but baby hippos will always be a draw for zoo visitors.

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