Colombia ‘shoots’ contraceptives to “cocaine hippos”

(CNN) – Colombia may have finally found a solution to one of the notorious drug lord Pablo Escobar’s lesser-known legacies: invading hippos.

A handful of hippos brought to Colombia in the 1980s for Escobar’s private zoo have grown to a population of 80, prompting biologists to express concern about their environmental impact and the threat to human safety. In January, a study published in Biological Conservation He asked for the growing herd, which is now in the wild in the department of Antioquia, to be euthanized.

Instead, the regional government has tried to castrate the huge beasts, but traditional surgical sterilization is too dangerous and demanding to extend to dozens of animals. Up to now, only 11 of the hippos they have been sterilized in this way, according to local authorities.

On Friday, however, the regional environmental agency Cornare announced that its efforts to control the hippo population had led to 24 more hippos being treated with a new method: darts loaded with the contraceptive drug GonaCon.

Compared to surgery, GonaCon is “a much cheaper option,” according to a statement from Cornare. “However, it remains complex, as experts suggest administering three doses, based on studies and comparisons made in other large animals such as horses.” The same drug has been tested in other wild animal populations, including wild horses in the United States, kangaroos in Australia and wild cattle in Hong Kong, he said.

Scientists must now track the drug’s effectiveness by measuring hormone levels in hippos’ feces.

“It is the first time we have implemented this procedure. We are going to follow up and monitor it to see how successful it can be,” said David Echeverri López, coordinator of the Cornare Forest and Biodiversity Group.

Cornare and USDA specialists involved in the hippo pilot project.

Escobar’s hippo collection started with a single male and three females. Upon their death, other species of exotic animals were relocated, but the hippos stayed because they were too difficult to capture and transport, according to the study by Biological Conservation. They soon began to multiply, spreading through the Magdalena river basin from their original home about 250 km east of the city of Medellín.

Research has shown the negative effects of hippo waste on oxygen levels in bodies of water, which can affect fish and ultimately humans. Hippos also pose a threat to agriculture and the safety of people in affected areas, according to the study by Biological Conservation. In May 2020, a hippo attack left a 45-year-old man seriously injured.

CNN’s Stefano Pozzebon reported from Bogotá, and Jack Guy contributed previous reporting from London.