The so-called "cocaine hippos" introduced by Esocbar to his private zoo, have grown from a herd of 35 in 2012 to 80 this year, and were thought to be the largest outside Africa.
Out of the 80 hippos, 24 have reportedly already been treated with a chemical that makes them infertile.
The overly-fertile descendants could potentially take over the country's marshlands and pose a threat to Colombia's natural wildlife since their urine and faeces are toxic, according to scientists.
Pablo Escobar, the kingpin of the world's largest cocaine empire in the 1980s, collected a range of illegally imported animals at his estate in Colombia, which included hippos, kangaroos, giraffes, elephants, and other exotic creatures.
In 1993, after Escobar's reign came to an end when he was shot dead by authorities, one male and three female hippos escaped from his 7,000-acre jungle hacienda between Medellin and Bogota.
"It was logistically difficult to move them around, so the authorities just left them there, probably thinking the animals would die", Colombian biologist Nataly Castelblanco reportedly told the BBC earlier this year.
Since then, the hippo population has grown and taken over the countryside.
Scientists warn that their numbers could soon be impossible to control and their environmental impact will be irreversible.