Pablo Escobar's Hippos Are Thriving in Colombia and Wreaking Havoc With Local Ecosystem

Colombian drug lord Pablo Escobar was known for his lavish spending—not surprising given he was one of the wealthiest criminals in history, He even imported several hippos to live at his luxurious country estate, around 90 miles east of Medellin, in the early 1990s. Now, researchers say that these invasive animals are having a big impact on the local environment.

For a study published in the journal Ecology, a team from the University of California San Diego (UCSD) and Colombian institutions conducted the first scientific assessment of how these hippos are affecting aquatic ecosystems.

"This unique species has a big impact on its ecosystem in its native range in Africa, and we found that it has a similar impact when you import it into an entirely new continent with a completely different environment and cast of characters," Jonathan Shurin, an author of the study from UCSD's Division of Biological Sciences, said in a statement.

"It's clear that this effect might include negative consequences for water quality and water resources by fueling harmful algae and bacteria," he said.

Escobar's luxury estate—known as Hacienda Napoles—in northern Colombia's Triunfo municipality housed a private zoo that housed several exotic animals, including elephants, ostriches, rhinos, giraffes, zebras and hippopotamuses.

Following Escobar's death in 1993 at the hands of the Colombian police, the government seized the property and most of the animals were donated to local and international zoos. However hippos are extremely difficult to catch and it was deemed too dangerous and impractical to move them from the ranch.

So the four hippos living there remained and multiplied over the subsequent years. The population has now expanded to around 80 individuals and spread beyond the confines of Escobar's estate into the small lakes dotted around the surrounding areas.

This has provided researchers with a unique opportunity to study the ecological impact of the world's largest invasive animal in a continent where creatures of this size have largely disappeared.

"The New World, North and South America, used to have many of the sorts of giant animals you only see in Africa today," Shurin told Newsweek. "Mammoths, mastodons, giant camels, saber-tooth tigers—but not hippos—were all found here. Their disappearance probably transformed ecosystems. The arrival and spread of hippos gives us a picture of how the loss of this whole group of organisms may have changed the world."

For their study, the scientists analyzed water quality and other environmental factors in the areas where the hippos roam over a period of two years. They found that the animals were altering the chemistry and biology of local lakes.

Pablo Escobar
The hippo population in Colombia. University of California San Diego

At night they feed on land, where they become covered in nutrients and organic material. Then in the daytime they move to the water, taking these materials with them. This can have negative consequences for the aquatic ecosystem.

"The effect of fertilizing all those bacteria and algae increases the productivity in the water," Shurin said. "We found that the lakes are more productive when they have hippos in them. This can change the kinds of algae and bacteria and can lead to problems like eutrophication, or excess algae production that can lead to harmful algal blooms similar to red tides."

The researchers predict the hippo population will grow significantly in the coming years, perhaps creating an even more pressing ecological problem.

"If you plot out their population growth, we show that it tends to go exponentially skyward," Shurin said. "In the next couple of decades there could be thousands of them. This study suggests that there is some urgency to deciding what to do about them. The question is: what should that be?"

According to Shurin, the latest results highlight the need for action to be taken soon before the problem spirals out of control.

"Likely their impact on the environment and interactions with the public will both increase," he told Newsweek. "That's why doing something about them now, when their numbers are not so great, is easier, cheaper and more humane than when they become more numerous and widely dispersed."

"There's a real dilemma about what to do about them in Colombia," he added. "On one hand, they're a local tourist attraction and curiosity. On the other, they pose a real risk to the public and the environment. There's real public resistance, in Colombia and elsewhere, to removing them by lethal means, but no resources to capture or sterilize them."