Study: Drug kingpin’s ‘cocaine hippos’ may be having positive impact on ecosystem

COLOMBIA—Colombian drug lord Pablo Escobar is known for his reign over illegal cocaine, eventually controlling more than 80 percent of the drug shipped to the U.S.

Meanwhile, the so-called four “cocaine hippos” he brought into the country are making their own legacy. The non-native hippos were set free after his death in 1993 and there are now about 80 of them living in the wild. What the country should do with them has long been debated and they have been accused of wreaking havoc on the local ecosystem. A study published in the journal Ecology in January, led by Jonathan Shurin at the University of California, San Diego, found hippo poop was helping fertilize algae and bacteria in Colombian lakes and potentially contributing to problematic algal blooms.

However, a study published in late March in the Proceedings of the National Academy of Science presented evidence for the opposite, stating findings showing the invasive animals may “restore ecological functions” lost for thousands of years due to “human driven extinctions.”

Researchers said the creatures could be filling the biological role once played by extinct animals like giant llamas, mammoths, giant sloths and giant wombats during the Late Pleistocene period about 116,000 to 11,000 years ago.

For the study scientists analyzed the ecological impacts of 427 large herbivores weighing at least 22 pounds that lived between 130,000 years ago and the present day, to see if ailing ecosystems that were once populated by herbivores could be restored to health if big herbivores came back. In Colombia, the renegade hippos “present a chimera of multiple extinct species’ trait combinations,” the study authors wrote.

“Many introduced herbivores restore trait combinations that have the capacity to influence ecosystem processes, such as wildfire and shrub expansion in drylands,” the study authors wrote. “Although introduced species have long been a source of contention, our findings indicate that they may, in part, restore ecological functions reflective of the past several million years before widespread human-driven extinctions.”