Pablo Escobar, the infamous drug lord from Colombia and the richest criminal in history, left behind an unexpected and uncontainable legacy after his death in 1993—a group of hippopotamuses. Escobar was fond of collecting exotic animals from all over the world to add to his private zoo located in his private estate, “Hacienda Napoles.” Ever the pioneer, Escobar unintentionally created the first ever non-African hippo population by importing four of the massive creatures from their natural habitat to his Columbian ranch. Following his premature death, authorities relocated the majority of the animals in his collection, but decided to leave the hippos alone due to their enormous size and aggressive behavior. This resulted in some unanticipated complications. Rather than dying out, the four have now multiplied into dozens, with some experts estimating there to be around 80-100 wild hippos roaming the Magdalena river basin, miles away from their original location.
The Colombian government is divided on how best to handle the growing population. The hippos pose many logistical challenges, making it incredibly difficult for people to handle and move them into enclosed spaces. Aside from the fact that they can weigh up to 4,000 pounds, hippos have also been documented to have violent interactions with humans, posing a threat to the local people surrounding the areas they now inhabit. The killing of a Colombian hippo in 2009 resulted in significant public outcry. Despite the potential conflict that can arise from hippos living in such close proximity to people, the hippos are idolized by the local people and tourists alike, with some estimating that their presence has attracted over 50,000 additional tourists to Hacienda. The government could potentially rely on options like sterilization or relocation into zoos as ways to curb the rapidly expanding population. However, these methods would be expensive and difficult, as the exact number and location of hippos remains unknown. As of now, the government has yet to devise a concrete plan for how to deal with the animals.
Scientists are also split on how the hippos are affecting the ecosystem they have adopted as their own. While researchers agree that the animals are essentially an invasive species by altering the natural environment, not all ecologists are convinced that this is necessarily a bad thing.
Hippos are creatures that are known for having a dramatic impact on their habitats, earning them the nickname “ecosystem engineers.” The animals feast on land and then excrete their waste into the water, resulting in the transfer of terrestrial nutrients into aquatic systems. This changes the chemistry of the water in which they reside, leading to a domino effect that in turn reaches all of the organisms living in the same area. For example, research shows that hippo dung can have a negative effect on the resident fish by making them more vulnerable to predation from terrestrial organisms. Additionally, due to their massive size, the animals can physically change the small-scale geography of the wetlands as they move their bodies through the mud and create water channels. These signature changes that hippos can inflict on their environments are natural to sub-Saharan Africa, but the effect that they can have on the native species of Colombia are yet to be seen and measured.
Scientists in favor of letting the hippo population remain undisturbed speculate that their presence might actually be a service to the ecosystems of Colombia. Hippo waste could increase the nutrients found in oxygen-poor water and contribute to an overall increase in biodiversity as a result. They can also control the population of certain grassy plants by becoming their primary predator. These are all roles that are taken on by large herbivorous species, but South America has largely been devoid of such animals for the last 20,000 years following the extinction of the hippo-like toxodon and tapir species. This is a phenomenon referred to as rewilding, where an existing species essentially assumes the ecological role of one that died out a long time ago. In his efforts of grandeur, Escobar initiated an accidental rewilding experiment with his unassuming hippos, one for which we won’t see concrete results anytime soon.
Having a second, nonnative population of hippos might serve as a conservation asset in the long-run as hippos are considered vulnerable to extinction. Despite the fact that they are an invasive species in Colombia, the future of hippos in Africa is uncertain. Their populations are decreasing in other parts of the world due to growing threats such as habitat loss and climate change. So, in some ways, a growing, global population can be a silver lining. Many eyes are on the future of the Colombian hippos, as scientists and the general population alike are charmed by their unlikely success story, and are eager to see the unprecedented impacts they may have on their new home.
Dutton, C. (May 16, 2018). Organic matter loading by hippopotami causes subsidy overload resulting in downstream hypoxia and fish kills. Nature. https://www.nature.com/articles/s41467-018-04391-6.
Guy, J. (January 19, 2021). Colombia’s ‘cocaine hippos’ must be culled, scientists say — but not everyone agrees. CNN. https://www.cnn.com/2021/01/18/americas/colombia-pablo-escobar-hippos-scli-intl-scn/index.html.
Wilcox, C. (January 31, 2021). Could Pablo Escobar’s escaped hippos help the environment? National Geographic. https://www.nationalgeographic.com/animals/article/colombia-cocaine-hippos-rewilding-experiment-news.