In 1981, four hippos from the United States arrived in Colombia, with another 1,200 animals, as part of a new, extravagant 2,000-hectare zoo in the Hacienda Nápoles. This reserve, owned by the famous drug baron Pablo Escobar, was enormous; it stood nearly ten times the size of Toronto Zoo in Canada, one of the largest zoos in the world, which covers 287 hectares.
In 2008, long after Escobar’s death in 1993, the state of abandonment of the large Hacienda Nápoles raised alarm among the Colombian scientific community. Escobar’s hippos had escaped, and scientists had identified, by then, that these animals were a latent biological threat. They were reproducing out of control and were soon to become an invasive species that would be difficult and expensive to manage.
People in rural and urban areas welcomed the hippos, which had been wrongly portrayed by media as cuddly and harmless animals. In addition, public interest in the hippos created a new hotspot of national and international tourism, stimulating the local favourability towards the presence of the animals.
At that time, public campaigns of environmental education were not prioritised and a pragmatic stance was assumed: controlling the hippos. The first sacrifice happened on June 16, 2009 and occupied the front pages of the media in Colombia and even the world, and the country was immersed in the first of many dramas to form around the hippos.
The hippos were overwhelmingly perceived as “friendly” and “harmless.” A lack of publicly available information, however, meant that people did not know they were also lethal, dangerous and carriers of disease. It was only in March 2022 that hippos were declared invasive species in Colombia, due to the serious environmental impacts they generate, the risk to people, and the serious attacks recorded.
However, the shifting public image of hippos—from cuddly and cute to dangerous—was countered by a parallel in the animal rights movement, which defended the hippos in the wild in Colombia, insisting on a humanising, pro-life agenda, which protested their euthanasia, ignoring the recommendations of technical and scientific studies.
It is difficult to reconcile animal rights positions with proper management of invasive species. Animal rights activism has an important electoral weight in Colombia across the political divide. After 14 years of continuous pressure, animal rights activists have managed to prevent the control and eradication of Escobar’s hippos. The growing size of the population, resulting among other things from the animal rights activism, makes conservation and eradication programs more costly, in both monetary and life terms: while initially it could have been circa 10 animals euthanised for conservation purposes, now it is estimated that there are more than 200 individuals—and the population is rapidly growing.
Furthermore, there is a strong time pressure on control efforts; if hippos continue to reproduce, the threshold for management and containment will be exceeded. As it is the case with dromedaries and feral horses in other latitudes, as time goes by, Colombia will have to embark on costlier strategies of permanent eradication of individuals. This ever-likely case scenario is the worst possible future, as it would involve the constant slaughter of animals and greater environmental problems that would affect people.
The urgency is at its highest. From an ecological, ethical and financial perspective, there is no time to lose; all efforts must be directed to prevent the hippos from establishing to the point that gets impossible to contain them.
However, tension still exists between animal rights and conservation perspectives. The current Minister of the Environment, Susana Muhammad, in an attempt to reconcile the two, proposed adapting an animal rights-approved proposal for the management of feral cats, which is unsuccessful according to the evidence, to the case of the hippos. This strategy consists of capturing, sterilising and releasing feral cats. In the case of hippos, such a proposal would translate to surgical castrations and release; translocation of individuals (sending them to other parts of the world); and euthanasia as last option.
The measure has been bittersweet in the eyes of the Colombian scientific community. Faced with decades of inaction, some are content with surgical castrations: doing nothing would be worse. However, others like Biodiversos—a multidisciplinary group of scholars working for policies on the study, conservation and sustainable use of Colombian biodiversity—consider that the Ministry of Environment was mistaken in not following the technical recommendations already given by the scientists.
Surgical castration followed by subsequent release is a costly and inefficient strategy, that is not contemplated in the management plan proposed by the scientists. According to them, the life expectancy of hippos in Colombia’s environment, without pressure from predators or long dry seasons, is longer than in their natural environment (approximately 4 or 5 decades). This has significant environmental impacts due to the ecosystem engineering capabilities of the species, which are dramatically changing the geography of the Magdalena Basin where they are quickly spreading and reproducing at the moment. The experts’ calculations suggest that the only alternative to mitigate the ecosystem impacts is to extract a minimum of 30 individuals per year.
The evidence indicates that five strategies should be implemented in parallel: euthanasia (control hunting) as a priority, especially in colonies that have been established in new areas; translocation; confinement; urgent implementation of an early warning system for immediate identification of new colonisation areas; and environmental information.
The order of these interventions does matter; euthanasia must come first. The animal rights demand to sterilise and release, while seemingly kinder, will not succeed on its own in Colombia for a few key reasons:
- It is the most expensive least efficient option, and financial resources are limited.
- Surgical castration is not part of species’ containment strategies, unless preceded by translocations or confinements.
- The life expectancy of hippos in Colombia is too high, releasing them exposes ecosystems to constant deterioration and people to enormous risk.
Colombia is responsible for containing the hippos, both to itself and to the world, as it could become a problem for Latin America as the population expands and migrates. Animal right activists’ positions privileging individual animals cannot take precedence over collective well-being.
This environmental conflict, while still ongoing, contains a lesson: environmental management plans must include (and prioritise) communities. This problem affects the entire country, but especially vulnerable inhabitants in the impacted rural areas who could see their subsistence affected by negative impacts on fish populations and who are also highly exposed to attacks such as those already registered in Puerto Triunfo. It is necessary to redouble public information efforts to facilitate an understanding of the magnitude of this problem among the citizens, and implement strategies that prioritize the needs of the ecosystem and community.
 For news pieces that humanise the hippos, see e.g. José Alejandro Castaño, “Dos hipopótamos tristes,” Letras Libras (June 30, 2008); “Hacienda Nápoles, un parque temático que intenta evadir la apología a su creador, Pablo Escobar,” El Tiempo (June 17, 2008).
 Natural Resource Management Ministerial Council (2010). National Feral Camel Action Plan: A National Strategy for the Management of Feral camels in Australia.
 ICN and IAVH. (2022). Convenio interadministrativo No. 862 de 2022 suscrito entre el Ministeiro de Ambiente y Desarrollo Sostenible, el Instituto de Investigación de Recursos Biológicos “Alexander von Humbodlt” – IAVH y la Universidad Nacional de Colombia, Facultad de Ciencia Instituto de Ciencias Naturales – ICN. Available here.
 For reference, see the management plan in the footnote 
*Cover image: Public domain.
[*Cover image description: A group of three hippos in a river.]
This post is an adaptation to English of the column “Se agotó el tiempo para controlar los hipopótamos de Escobar” for the online news portal RazonPública. Adapted for EHN with assistance of Diana Valencia-Duarte.
Edited by Livia Regina Batista and Diana Valencia-Duarte, reviewed by Emily Webster.