Loaded For Bear: are the feral hippos of a Colombian drug lord alien invaders or ecological trend-setters?

9 Sep 2024

A population of feral hippos in Colombia is a bizarre legacy of the late drug lord Pablo Escobar. A court last week ordered that the animals be hunted and sterilised on the grounds that they are affecting the area’s “ecological balance”. But some conservationists have maintained that the critters are actually restoring the region’s ecological integrity.

Pablo Escobar was a vicious cartel boss who happened to have a thing for animals. The result has been an inadvertent experiment in what conservation scientists call “Pleistocene rewilding”.

Escobar had a menagerie of exotic species on his Colombian estate that included lions, giraffes and hippos. After his death in 1993, the hippos escaped into the surrounding countryside and their numbers have since swelled from four to an estimated 200 or more.

Read more: Colombia’s ‘Cocaine Hippo’ Population Is Even Bigger Than Scientists Thought

The Administrative Court of Cundinamarca on Friday last week ordered Colombia’s Environment Ministry to draw up regulations for the eradication of the animals on the grounds that they are affecting the area’s “ecological balance”.

Read more: Colombia orders hunting of Pablo Escobar’s out-of-hand hippos, after decades of failed eradication efforts

It’s not the first time that the “cocaine hippos” have been in the crosshairs. In 2009 the shooting of one deemed to be a threat to people and crops — which had the nickname “Pepe” — triggered protests in Colombia and led to a ban on hippo hunting.

Read more: Pablo Escobar’s fugitive hippo shot dead

Hippos are known for their ferocity and kill, by some estimates, hundreds of people each year in Africa — the only continent where they currently naturally occur.

In Colombia, there have been reports in recent years of two serious attacks on humans by the animals.

Read more: Colombia’s ‘cocaine hippos’: a problem too big to ignore

Any threat to human life would warrant a cull, finish and klaar. But doing so on ecological grounds is perhaps questionable.

Lost world

In South America, hippos are regarded as an alien or invasive species. But that does not necessarily mean that their presence is an ecological threat.

One offshoot of the wider “rewilding” movement — which broadly seeks to restore wildlife to historic ranges and landscapes — are initiatives to recreate the lost world of the Pleistocene.

Advocates of “Pleistocene rewilding” generally hold the view that the extinction of dozens of mostly large mammal species worldwide between 130,000 and a few thousand years ago was primarily triggered by ancient human hunters, making it the first round of what has been dubbed the unfolding “Sixth Extinction”.

This is hotly contested scientific terrain — climate change is seen as the other major cause — but for Pleistocene rewilders, the premise that these megafaunal extinctions can be traced to humans implies that they were unnatural.

And if they were unnatural, then one way to restore ecological integrity and biodiversity is to return megafauna — which are regarded as keystone species because of the outsized role they play in the environment — to the Pleistocene ranges the animals once roamed in the Americas, Europe and Asia.

This does not have to be like-for-like but would involve, say, translocating African elephants to ranges where mammoths or mastodons were once found.

Or hippos to South America.

A 2020 study in the US Proceedings of the National Academy of Sciences found that Escobar’s hippos were helping to restore a lost ecology.

Read more: Introduced herbivores restore Late Pleistocene ecological functions

“While we found that some introduced herbivores are perfect ecological matches for extinct ones, in other cases the introduced species represents a mix of traits seen in extinct species,” said study co-author John Rowan, a Darwin Fellow in organismic and evolutionary biology at the University of Massachusetts Amherst.

Read more: Pablo Escobar’s hippos may help counteract a legacy of extinctions

“For example, the feral hippos in South America are similar in diet and body size to extinct giant llamas, while a bizarre type of extinct mammal – a notoungulate – shares with hippos their large size and semiaquatic habitats. So, while hippos don’t perfectly replace any one extinct species, they restore parts of important ecologies across several species.”

Among other things, hippos transfer vast amounts of nutrients and energy from the land where they graze to the aquatic ecosystems where they spend much of their time. Hippo dung is a vital source of food for many African species of freshwater fish. And regional collapses of the pachyderm’s population have been linked to collapses in fish populations.

Read more: Hippo dung provides important nutrients to river fish and aquatic insects

So the drug baron’s hippos may be good for the waterways in Colombia where they are now found.

Escobar almost certainly did not mean to advance the cause of science when he acquired four hippos for his exotic zoo. But while it may sound like a drug-induced epiphany, the descendants of that quartet have provided a real-life experiment in Pleistocene rewilding.

So eradicating the animals from Colombia could undermine our attempts to reclaim a lost world. DM

https://www.youtube.com/watch?v=REeWvTRUpMk

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Lost world