A herd of ‘cocaine hippos’ from Pablo Escobar’s private zoo are being sterilized

The 80-strong bloat, originally part of the Colombian drug lord's estate, present an environmental concern as an invasive species

A group of rampant hippopotamuses, introduced by the late Colombia drug lord Pablo Escobar to his private zoo, are being sterilized by the country's wildlife services, after mounting concern that the 80-strong herd presented a potential environmental disaster as an invasive species.

The so-called cocaine hippos", whose number has more than doubled since 2012, were sterilized after worries have mounted over their environmental impact, including a threat to human safety.