Drug kingpin Pablo Escobar had a private zoo in Colombia, in which he kept all sorts of exotic animals, including hippos.
But when Escobar's estates were seized in 1993, the animals were taken to different zoos. Except for the hippos. The hippos were problematic to move and they were left on the estate — one male and three females. They didn't die. They managed to get to the River Magdalena, which boasted ideal conditions. They thrived, and today an estimated 80 to 120 hippos live in Colombia's rivers. Their numbers could reach 1,400 in 20 years.
In the local rivers they could threaten the beloved manatees and fish. Biologists are considering whether they should be killed or sterilized.