God’s creativity is on full display in the barrel-shaped hippopotamus. These massive beasts are some of the most unusual mammals on Earth. And in the tropics of Colombia, South America, a herd of them is causing a ruckus—and stirring up colossal controversy.

In the 1980s, the sprawling estate of drug kingpin Pablo Escobar was home to a private zoo of illegally imported animals. In addition to kangaroos, giraffes, and elephants, he arranged for three female hippos and one male to be brought to his estate from the United States. After Escobar’s death in 1993, authorities relocated some of the animals. But the expense and trouble of transporting the three-ton behemoths caused Colombian officials to abandon the hippos to the wild.

Now those hippos are flourishing. And like the man who brought the animals to the Colombian jungles, they’re a source of big problems.

Unlike in Africa, hippos living around Colombia’s Rio Magdalena river have no natural predators. Therefore, the hippo population has grown out of control. It has exploded from 35 animals to between 65 and 80 in eight years. Experts say hippo numbers could reach 1,500 by 2035!

Some scientists warn that the hippos pose a major threat to the area—and could lead to deadly encounters between the huge animals and humans. The aggressive beasts kill more people per year in Africa than any other wildlife species.

One solution scientists suggest is culling the herd. Culling involves selecting unwelcome animals to slaughter.

Meanwhile, the hippos threaten not only humans but also other animals. One study last year found that hippos are changing the quality of the water in which they spend much of their time and, well, go potty.

Researcher David Echeverri-Lopez is seeking a solution to the hippo problem. He knows culling would be the best solution. But he says the hippos’ appeal and government laws over hippo hunting may never allow it.

Colombians in this rural area have embraced the hippos as their own, in part because of the tourist dollars they bring in. Plus, according to veterinarian Gina Serna-Trujillo, Colombians are protective of the beasts because “they love them.”

Ecologist Nataly Castelblanco-Martínez understands the hippos’ charm. She describes a baby hippo as “the most beautiful thing in the world” but says the animals’ future in Colombia should not be ruled by warm feelings.

“You can’t even talk about [culling hippos] because the rejection is staggering,” Castelblanco says. “I am being called a murderer.”

Why? While God created all animals according to their kinds and set them around the world in perfect balance, human actions like transporting them to other places can have unintended consequences.