Contraceptive Darts: The Birth Control Colombia Is Using For Its Hippos To Stop Over-Breeding

The hippos are a legacy of Colombia’s deceased drug lord Pablo Escobar who had imported the animals for his private zoo. The country is now struggling to control their population

Hippos at the Hacienda Napoles theme park, once the private zoo of drug kingpin Pablo Escobar, in Doradal, Antioquia department, Colombia | Photo: AFP

New Delhi: Colombia, struggling to control its oversized hippopotamus population, has started to dart the animals with adapted contraceptives to stop over-breeding, new agency Reuters reported. 

The hippos, native to Africa, are a legacy of Colombia’s deceased drug lord Pablo Escobar who had imported them for his private zoo, the report said.

The Animal and Plant Health Inspection Service (APHIS) of the US Department of Agriculture is said to have donated 70 doses of the GonaCon contraceptive to neuter the animals.

The contraceptive darts are normally used to control deer populations.

According to APHIS website, GonaCon works by stimulating the production of antibodies against gonadotropin-releasing hormone (GnRH), which is “a key reproductive hormone needed to produce estrogen and progesterone and to trigger ovulation”.

David Echeverri, coordinator for forests and biodiversity at Cornare, a regional environmental authority, told Reuters that around 90 hippos, descendents of those Escobar brought into the country over 30 years ago, are thought to be roaming around Colombia.

Escobar reportedly bought four hippos from a zoo in California, and flew them to his Napoles ranch in the early 1980s. They bred to become supposedly the biggest wild hippo herd outside Africa, which is both a local curiosity and a hazard, AFP reported in 2020. 

According to a study published in the Biological Conservation journal, the invasive animals could attack people and destroy crops, and their waste threatens water environments. Neutering the hippos through surgical sterilisation is considered risky, and costly too.

The APHIS is hoping the darting campaign will help stop the population growth of the hippos. 

Jason Bruemmer, project leader for fertility control at APHIS, told Reuters that the numbers have to be controlled now, “before it gets to the thousands, before people get killed and more of the environment gets negatively affected".