Hippopotamuses brought to Colombia as part of Escobar's private zoo at his ranch, Hacienda Napoles, have bred so successfully that there is serious concern over their environmental impact and human safety, according to a new study by researchers at Mexican and Colombian universities.
The hippos have spread out from their original home, some 100 miles east of the city of Medellin, in the Antioquia department, dispersing around the Magdalena river basin as their population continues to grow steadily.
The authors of the study, published in the January edition of the journal Biological Conservation, recommend that the hippos be culled to prevent long-term negative effects, but other scientists are calling for a castration program to control the hippo population, citing concerns over animal welfare and the attachment of some locals to their new neighbors.
Back in the 1980s, Escobar imported one male and three female hippos to join his menagerie. Upon his death, other species of exotic animals were relocated, but the hippos were left because they were difficult to capture and transport, according to the study.
The hippos soon began to spread in the surrounding area, but government efforts to cull them were halted after a public outcry.