In the 1980s, drug lord Pablo Escobar smuggled four hippos into Colombia for his personal zoo. But wild hippos are only native to the African continent, and their escape after Escobar’s death left Colombia with an unexpected problem: There are now dozens of hippos roaming around one of the country’s rivers.

This latest episode of Vox Borders looks at how these hippos affect Colombia’s biodiversity, and how people became fond of their presence.

Borders is a series from Vox’s Johnny Harris in which he travels the globe to listen to the people living on the front lines of international relations.

You can find this video and all of Vox’s videos on YouTube. Subscribe for the latest.