For decades, the hippos that Pablo Escobar smuggled into Colombia as exotic pets have been multiplying in the warm waterways of the Magdalena River basin, growing from a handful of animals into a population that now numbers somewhere between 80 and 170, depending on the estimate. In April 2026, Colombia’s Ministry of Environment and Sustainable Development took its most aggressive step yet: approving, for the first time, a technical protocol that allows veterinary teams to euthanize some of the animals.
The decision marks a turning point in a saga that has pitted ecological science against public affection for one of the world’s strangest invasive species. Hippos have become a roadside attraction in the Magdalena Medio region, drawing tourists to the area around Escobar’s former estate, Hacienda Napoles. But scientists and government officials say the animals are degrading rivers, threatening farmers and fishers, and spreading faster than any non-lethal program can contain.
From Escobar’s zoo to ecological emergency
In the 1980s, Escobar imported four hippos to stock the private zoo at his sprawling ranch in Puerto Triunfo, Antioquia. After his death in 1993, most of the exotic animals were relocated or died, but the hippos were left behind. They escaped into the Magdalena River system, where warm temperatures, abundant water, and the absence of natural predators like lions and crocodiles created near-ideal breeding conditions.
The population grew quietly for years before attracting serious scientific attention. A peer-reviewed study published in Scientific Reports modeled the hippos’ population dynamics and projected that without aggressive intervention, their numbers could surge dramatically within a decade. The researchers evaluated combinations of sterilization, translocation, and culling, and concluded that sterilization alone cannot keep pace with the animals’ reproductive rate. Costs, they found, rise steeply with every year of delay.
Separate ecological research published in the journal Oryx has documented how hippos alter aquatic ecosystems through massive nutrient loading. Their dung changes the chemistry of rivers and lakes, fueling algal blooms, reducing water quality, and threatening native fish and invertebrate species. The same research reviewed the socio-economic toll on rural communities: damaged crops, dangerous encounters along riverbanks, and safety hazards for fishers who share the water with multi-ton animals known for territorial aggression. Note: The specific Oryx study is referenced in government and media materials but no author, year, title, or direct link has been independently confirmed for citation purposes.
What the government’s plan includes
The legal foundation for the new approach is Resolucion 0774, which formally classifies the common hippopotamus as an exotic invasive species in Colombia and establishes a prevention, control, and management framework. Building on that resolution, the ministry activated what it calls a “plan de choque integral,” or comprehensive emergency plan, described in a public bulletin outlining the government’s strategy to halt the hippos’ expansion.
Euthanasia is one tool within a broader kit that also includes surgical sterilization, chemical contraception, physical containment, and potential relocation to foreign zoos or sanctuaries. The ministry has emphasized that the euthanasia protocol is a veterinary-guided procedure, not an open cull. Officials say it must comply with animal welfare standards, including the use of trained personnel, appropriate sedatives or anesthetics, and methods designed to minimize suffering. The protocol is intended for targeted use in priority zones where hippos pose the greatest ecological damage or physical danger to people.
Earlier control efforts help explain why the government escalated. Surgical sterilization requires darting and capturing a two-ton animal in murky river water, a process that is expensive, dangerous, and slow. Chemical contraception delivered via dart has been tried on a limited basis but is difficult to administer consistently across a scattered, semi-aquatic population. A small number of hippos have been relocated to international facilities, but finding zoos willing and equipped to accept them has proven a logistical bottleneck. None of these methods, officials argue, have kept pace with the breeding rate.
Courts forced the government’s hand
The euthanasia protocol did not emerge from the executive branch alone. The Ministry of Environment has acknowledged that a ruling from the Tribunal Administrativo de Cundinamarca directed it to regulate eradication measures, giving the judiciary a central role in pushing the government toward lethal control. The date of that ruling has not been specified in publicly available ministry materials. A separate judicial order, Auto Interlocutorio 2023-09-463, is tied to an ongoing popular legal action and includes mechanisms for receiving public proposals on managing the animals.
These court interventions mean the plan is partly a response to legal obligations, not just a policy preference. However, the underlying court documents have not been made publicly available through the ministry’s portal, so it remains unclear whether judges set specific deadlines, mandated population reduction targets, or required the state to exhaust non-lethal options before resorting to euthanasia.
What remains unresolved
The full downloadable text of Resolucion 0774 was not accessible through the ministry’s website at the time of reporting. This means the specific criteria for selecting individual hippos for euthanasia, the veterinary methods to be employed, and the timeline for the first operations have not been independently verified from the resolution itself. Until the document is available for review, key operational details of the plan rest on official summaries rather than primary legal text.
The total number of hippos in Colombia is itself an open question. The Associated Press reported the plan targets up to approximately 80 animals, but other estimates run higher. The Scientific Reports study modeled growth scenarios using different baseline figures, and those projections vary depending on assumptions about reproduction rates and juvenile survival. Without a recent, comprehensive government census, the true count remains a range rather than a firm number.
Geographic spread is similarly uncertain. The original population around Hacienda Napoles has expanded along the Magdalena River and into connected wetlands, but no publicly available, ministry-verified map shows all known subpopulations, their sizes, or their proximity to sensitive ecosystems and human settlements.
Then there is the question of public backlash. Hippos have become a tourist draw, and some local economies in the Magdalena Medio region have built informal revenue around hippo sightings. Animal rights advocates have seized on the hippos as a high-profile symbol in debates over the legal status of sentient animals. In 2021, a U.S. federal court recognized the hippos as “interested persons” in a legal proceeding, a largely symbolic but widely publicized moment. Whether organized legal or political opposition will slow or block the euthanasia campaign remains to be seen.
Funding and capacity are practical wildcards. The ministry has not released detailed budget figures for the emergency plan, nor has it specified how resources will be divided among euthanasia, sterilization, monitoring, and community outreach. The number of trained teams, the regions they will cover, and the pace of operations are all undisclosed. These details will determine whether the protocol becomes a meaningful population control measure or remains largely on paper.
Why delay is the most expensive option
What makes Colombia’s hippo problem so difficult is the collision of timelines. The animals breed reliably, face no natural predators in South America, and have access to vast stretches of suitable habitat. Every year without effective control adds animals to the population and pushes them into new territory, making future intervention harder and more expensive. The Scientific Reports modeling underscored this point: delay is the most costly option of all.
At the same time, hippos occupy an unusual space in public imagination. They are charismatic megafauna, widely loved in popular culture, and their origin story as remnants of a drug lord’s private zoo gives them a narrative power that invasive carp or feral pigs do not enjoy. That tension between ecological urgency and emotional attachment is what has stalled action for years and what makes the government’s new protocol so politically charged.
Colombia has now created the legal and technical pathway for culling part of the population. Whether officials will use it aggressively, cautiously, or barely at all depends on operational realities, court oversight, and a public debate that is only beginning to intensify.
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*This article was researched with the help of AI, with human editors creating the final content.
