Hippos brought to Colombia as part of Escobar’s private zoo on his farm, Hacienda Napoles, have grown so successful that there is serious concern about their impact on the environment and human safety, according to a new study by researchers from Mexican and Colombian universities.
Hippopotamuses spread from their original home, about 100 miles east of the city of Medellin, in the department of Antioquia, scattering around the Magdalena River basin as their population continued to grow steadily.
The study’s authors, published in the January issue of the journal Biological Conservation, recommend that hippos be eliminated to prevent long-term adverse effects, but other scientists are calling for a castration program to control hippos, citing animal concerns. the well-being and attachment of some locals to their new neighbors.
In the 1980s, Escobar imported a male hippo and three females to join his household. At his death, other species of exotic animals were relocated, but hippos were left because they were difficult to capture and transport, according to the study.
Hippos soon began to spread in the surrounding area, but government efforts to eliminate them were halted after a public protest.
Instead, a sterilization campaign was started, but it did little to slow the progress of the hippos.
From 2011 to 2019, four males were castrated and two females were sterilized, but this “does not appear to have a significant impact on reproduction,” according to the study.
Researchers say there are probably more than 80 hippos in the area today, up from 35 in 2012, and they worry that hippos will continue to spread across Colombia if no action is taken.
The study also cites research showing the negative effects of hippopotamus waste on the level of oxygen in water bodies, which can affect fish and, ultimately, humans, and raises concerns about the possible transmission of diseases from hippopotamuses to people.
Hippos also pose a threat to the livelihoods and safety of people in affected areas, the study said, eating or damaging crops and engaging in aggressive interactions with humans.
Researchers cite the incidence of hippos chasing people, as well as a hippo attack in May 2020 in which a 45-year-old man was seriously injured.
But while the study’s authors recommend elimination, Enrique Zerda Ordóñez, a biologist at Columbia National University, believes castration programs are the way to go.
Canceling hippos would be an “easy option,” Zerda said, but could affect the survival of a species that is threatened in Africa.
Although sterilizing hippos is not an easy task, he said, he believes it is possible and necessary to do so now, before their numbers increase further, according to a university press release.
“At this time, authorities do not consider the species a problem,” Zerda said, “but in the future, when there are 400-500 hippos, it could pose a threat to the survival of other species feeding in the same areas.”
David Echeverri Lopez, head of forests and biodiversity at the CORNARE regional environmental agency, told CNN that the situation is delicate.
“The option to kill them was always on the table,” he said. “However, it is very difficult to imagine that this could happen at this time.”
While hippos are an invasive species capable of completely changing local ecosystems, people in the area have become accustomed to them, Echeverri said. They have become a tourist attraction to which people feel a certain affection, he added.
Some hippos will have to be killed because it is “virtually impossible” to find and move or sterilize them.
“But there are other animals that are located in certain areas, in lakes and places that allow the implementation of a birth control plan, assuming that adequate resources are available,” said Echeverri, who works with the NGO Animal Balance to try to find alternative solutions.