Scientists Debate The Fate Of Pablo Escobar's Rogue Hippos


Tom Hale

Senior Journalist

clockJan 22 2021, 11:48 UTC
Hippo in Colombia.

A pack of hippopotamus frolicking around in Colombia. Image credit: Guillermo Ossa/

Pablo Escobar’s hippos, once again, are kicking up controversy in Colombia. 


In the 1980s, the Colombian cocaine kingpin splashed some of his millions on a private zoo at his ranch Hacienda Nápoles, including four illegally imported hippopotamuses. When Escobar died in 1993 and his empire dissolved, much of his property was confiscated by Colombian authorities, but the hippos were left to roam the marshlands of Colombia.

Although native to Africa, the hippos have made themselves at home around Colombia’s Magdalena River basin. Recent years have seen conservationists become increasingly worried about the ecological implications of the hippos’ presence, and some say the species have become an "invasive mega-vertebrate" to South America. In a new study reported in the journal Biological Conservation, a team of scientists looked to assess the risk of this invasive species and proposed some ideas of how to deal with the rogue animals. 

The introduced hippo population has blossomed from 35 individuals in 2012 to between 60 to 80 individuals in 2020, all related to the original foursome imported by Escobar. As per the new study, the population has been growing at an annual rate of 14.5 percent and could reach a population size of 1,418 by 2039.

The researchers note that these giant creatures can have a dramatic effect on an ecosystem's waterways. Hippos predominately poop and pee in river water, which can significantly increase the water's concentration of phosphates and nitrogen. In turn, this can have a profound effect on the microbial life in the rivers, favoring the growth of potentially toxic cyanobacteria. 


Hippos can also harbor a range of zoonotic diseases and parasites that could pose a risk to other species of wildlife. The study notes: “Some of these diseases or parasites could be potentially transmitted from introduced hippos to wild and domestic animals and ultimately, humans.”

On top of this ecological risk, the hippos also pose a risk to local communities. They might have a cuddly image, but hippos are extremely aggressive creatures and are considered one of the deadliest animals in Africa. While the scale of the problem isn’t clear, there have been a handful of reports, anecdotes, and video clips detailing hippo attacks on humans in Colombia, the researchers say.

They argue all of these problems will deepen in years to come considering how rapidly the hippo population is growing. To fix the problem, they suggest implementing a management strategy that would see the “extraction” of 30 hippos per year, heading towards population eradication in 2033. That’s basically a polite way of saying the hippos should be killed until the population is eradicated from South America. While the researchers realize this a controversial idea, they argue that other attempts to manage the hippo population, such as sterilization, have fallen flat. 


“Strategies need to be implemented quickly in order to control the expansion effects of this introduced species. Our projections indicated that the only course of action that could probably lead to the extirpation of this exotic species is to implement a high-level extraction by culling,” the study concludes.

“However, as the hippo is a highly charismatic species, this approach is not free of controversy.”