A group of hippos - an unwanted legacy following the death of notorious Colombian drug lord Pablo Escobar - are being sterilised. Escobar, who was shot dead by police in 1993, illegally imported exotic animals, including a male and a female hippo - dubbed the "cocaine hippos". Since then, a growing population has been taking over the countryside near his former ranch, Hacienda Nápoles. The Colombian government has so far sterilised 24 of more than 80 animals. They have been treated with a chemical that will make them infertile. Colombian environmentalists say the hippos, believed to be the biggest herd...