In the 1980s, the infamous drug lord Pablo Escobar imported 4 hippos onto his estate in Colombia. Today, the hippos have escaped the estate and they number around 60 individual animals and continue to reproduce. To mitigate risk of harm to humans and curb hippo population growth, the government has begun an effort to castrate the males in order to control their numbers. How effective are these efforts? Perhaps it is possible that leaving these hippos in Colombia may bring more benefits into the environment than harm, and allowing them to expand their population and habitat may not be as bad of an idea as it sounds. In addition, what moral questions do these hippos raise in a world where natural spaces grow ever smaller.

It is vital to recognize the guiding principles of Compassionate Conservation when considering how a country should handle such an issue. These principles being: Do no harm, recognizing the importance of individual wild animals, de-categorization of wild animals, and co-existence. When dealing with this issue, it is perhaps necessary to reconsider the categorization given to these animals as, “pests,” or, “invasive,” while taking into account all possible options before causing unnecessary harm and suffering to cognizant beings (Ramp, 2015). In a world that has changed beyond recognition over the last century, it is crucial to recognize the option of co-existence when possible, and the benefits it may bring (Lundgren, 2017; Wallach, 2015).

“Pablo always loved animals. When he was very young he had a book with pictures of all the animals in the world and he had an inexplicable obsession with the page on hippos,” Recalls Roberto Escobar, the older brother of Pablo, in the documentary “Los Hipopotamos del Capo.” “The day that he moved into his ranch he had me order the hippos from a zoo in the states and he was up all night on the radio checking to see that they were on their way and alright,” (Velez Dominguez, 2011). The drug lord imported 4 hippos, 1 male, and 3 females, to his private 7,000-acre ranch and zoo named “Hacienda Napoles.” Since the capture and fall of Pablo Escobar in 1991, most of the animals have been taken to zoos around Colombia. The hippos (Hippopotamus amphibius) however have been left to their own devices due to their enormous size as well as the difficulties and dangers of transporting them. Today, their numbers are estimated to be somewhere between 30 and 60 animals. With no natural predators, perfect climate, and unlimited space to roam the population of these “foreigners” is showing no signs of getting smaller.

Since the population explosion of the enormous African animal three options have arisen to control their numbers. Castration, control of the population in the ranch, and killing them for their meat. However, each control option seems to be fraught with difficulty. According to experts, hippo meat is dangerous since it may carry harmful diseases (Howard, 2016). In addition, a government lead effort to kill the hippos caused a large public outcry after a single individual was killed. This eventually ended the idea of killing the remaining hippos. The local authorities then decided to implement the option of castration and relocation; however, this option is much more difficult than it sounds. In order for a hippo to be castrated, it must be sedated while on land (because in the water they will very easily drown) and while they are alone so that other hippos cannot attack. The nocturnal society of hippos and dense herd lifestyle make this very difficult. Even if a bull is successfully found alone outside of water and the operation can be performed another problem arises. Hippos are extremely sensitive to chemical changes in their body and sedation can easily kill even a full-grown male (Kremer, 2014). A bull who has strayed far from the ranch must be sedated, castrated in the field, and brought via helicopter back to the ranch; this process often happens in the presence of the Colombian army (Los Hipopotamos del Capo). The entire process is extremely difficult and dangerous to both the hippos as well as to the humans performing the castration. Castration requires all of the males to be treated. If even one male is left without being castrated then the entire process will prove to be a failure as he will fertilize all of the females. In other words, castration may not be such a realistic option (Kremer, 2014).

Today, the presence of such giant creatures in Colombia seems to be a bit far-fetched and unnatural. However, the Colombia of 15,000 years ago was very different from the Colombia of today. The country was filled with giant ground sloths that stood 6 meters high, several species of elephant, large lamas, and of course saber tooth tigers. Shortly after the arrival of humans in the Americas these ancient and giant species of “megafauna” could not handle the burden of the human invaders and were soon enough hunted to extinction and wiped off the face of the continent and planet (Barnosky, 2004; Bartlett, 2015; Sandom, 2014). These large species played a crucial role in shaping the environment that they lived in through seed displacement and carrying nutrients over huge patches of land. Since their disappearance, it is estimated that in some parts of the continent less than 1% of the nutrients that used to be transferred across the surface of the continent are now transferred today by much smaller animals (Doughty, 2016; Mahli, 2016; Doughty, 2016). A new effort is being made around the world called “rewilding,” which aims to restore certain species that would have a similar effect in shaping the environment as locally large and extinct animals. There are a number of successful examples of rewilding efforts with far-reaching consequences. The reintroduction of wolves to Yellowstone national park which entirely reshaped the environment and ecology of the park. The wolves changed the behavior and habits of the caribou which in turn impacted the vegetation structure and ultimately altered the course of the rivers in the park. A Pleistocene park has already been built in Siberia. Large animals such as muskoxen, wolves, lynx, reindeer, and horses were reintroduced in order to investigate their impact on the Siberian environment that these animals create. Although the project is still only in its early stages, there are high hopes that the efforts will turn the frozen tundra into grass steppe (Zimov, 2005). Plans are also being made to restore elephants to their ancient Danish stomping grounds (Gabbatis, 2006), and the idea was proposed to build a massive megafaunal park with lions and elephants in the heart of the United States (Donlan, 2005; Donlan, 2006). These efforts may also reduce the threat of extinction that almost half the species on earth now face. Large wildlife is often considered “umbrella species,” whose ability to exist depends entirely on the health of the eco system that they inhabit. Therefore, in protecting large wildlife, an entire eco system is protected. If studies show that the hippos bring benefits to the Colombian wilderness, then could that open the door to brave new projects around the world for rewilding?

In the case of hippos (the second largest land-animal in the world) in the heart of Colombia, conservation experts advise for their removal. They are deemed a threat to the local environment, native endangered species (specifically giant otters and manatees), and human life. Hippopotamuses within their native range in Africa are kept in check due to the dry season which creates a significant shortage of food; in tropical Colombia where the dry season is not as harsh as it is in much of the hippos’ territory in Africa, it is believed that their populations can increase dramatically by 50% per year (Kremer, 2014). However, there are also natural populations of hippopotamus in The Democratic Republic of Congo which boasts the second largest rainforest in the world after the Amazon, and is, in fact, similar to the damp Colombian climate that the invaders now call home. It is difficult to say what would naturally keep the population of these hippos in check since the number of hippos in the Democratic Republic of Congo have declined by approximately 95% in recent years due to human activity and hunting (Lewison, 2007). This is more reason why a rewilding effort in Colombia could be essential to saving one of the most iconic species on earth. However, it also means that more studies are necessary to investigate the full impact of hippos on such a lush environment.

Hippos in Colombia might not be threatening to local species as automatically assumed. Hippos share many water ways in Africa with the same species that are present in the rivers of Colombia. In several sub-Saharan countries hippos live alongside otters and manatees (Jacques et al., 2015; Keith Diagne, 2015; Lewison and Pluháček, 2017; WWF, 2017).

There is no evidence that hippos have a negative effect on the populations of these animals. In fact, the opposite may be true. Hippos graze on land and then sleep in rivers during the day, they release enormous amounts of nutrients into the rivers that they inhabit, which increases the amount of aquatic vegetation on which manatees feed but hippos rarely do (Grey, 2002). Also, invertebrates and fish on which otters eat. In addition, this process may bring up the numbers of black caiman which can, in turn, play a part in controlling the number of hippos by killing the young since there is evidence showing that crocodiles possibly feed on young hippos in Africa (Kingdon, 1988; African Wildlife Foundation, York, 2014). Studies have shown that hippos are a crucial part of maintaining fish populations and entire river food systems (Mosepele, 2009; Masese, 2015).

The introduction of hippos may cause “eutrophication,” a sudden overabundance of previously unavailable nutrients and compounds leads to algal blooms (Howard, 2010). It is an uncommon event (when driven by natural processes), which usually occurs in lakes and not rivers. In addition, it is possible that the hippos may be carriers of parasites or diseases native to Africa and not to Colombia. These diseases could have enormous effects on the local species of Colombia however as of yet there is no proof that the hippos carry any foreign agents that could harm their new environment. Cattle of all kind are also “invasive species” in Colombia causing endless destruction, but their presence near the Magdalena river is for the most part accepted.

An example of a mixed effect of a large exotic species on a new environment is the introduction of the Asian water buffalo (Bubalus bubalis) to northern Australia in the nineteenth century. The buffaloes have many negative effects on the environment such as soil erosion, displacement of many small vertebrates, vegetation loss, carrying infectious diseases such as tuberculosis, and a change in the chemistry of the water (Australian Department of Sustainability, 2011). Despite these negative changes they also effected their environment in certain positive forms such as increasing the growth rate of trees and reducing their mortality rate across the buffalo habitat. The buffalo therefore have a positive effect on the savannah environment of northern Australia (Werner, 2005). In addition, there is also evidence that the buffalo have a positive effect on the wetlands by replacing fires as a means of controlling the growth of grasses, and indirectly creating micro habitats for amphibians and reptiles by trampling (Friend, 1990). In addition to the case of the water buffalo of Queensland Australia there is also the case of feral Dromedary camels (Camelus dromedarius). The camels which were introduced in the early 20^th century as porter animals proved to be perfectly adapted to survive the harsh conditions of the outback desert in addition to their ability to digest over 80% of local vegetation. They fill a void in the Australian habitat that was left by the extinction of megafauna (Lundgren, 2017). However, with no major predators other than dingoes which occasionally eat calves, their numbers have grown exponentially. Human-camel conflicts have arisen as camel’s number approximately 300,000 individuals (Deel, 2014) and cause severe damage to infrastructure, local economies, and possibly the environment (Deel, 2014; Lamb, 2010). Their population is “managed” often with brutal strategies such as ground or air culling. In contrast, Australia is now the only country in the world with wild populations of Dromedary camels that have been extinct in the wild for thousands of years (Lundgren, 2017). In the example of camels in Australia it is possible to see what happens when a large animal fills an ecological void that has not been filled for thousands of years.

Another challenging issue with hippo introduction is their threat to human life. It has been said that hippos cause more deaths per year than any other animal in Africa. Although this is a topic that is debatable the fact that these are amongst the most dangerous wild animals in the world cannot be argued. However, what does this mean for large wildlife around the world? that everything larger than a rabbit or sparrow should be killed because they threaten us? Is it impossible to find a way to live near wild animals on this planet without killing them? Perhaps with a little bit of will and ingenuity, a solution can be found for any problem. Take Richard Turere for example. He grew up on the Kenyan savannah tending his family’s cattle and at the age of 9 invented what is now called “Lion Lights,” which are a cheap and simple set of lights that cover the perimeter of a house or ranch that flash in sequence and give lions and other large predators the impression of a human guarding with a torch. Until now these lights have proven to be successful against lions and may also work against other large animals. Another example would be chili fences. An elephant is capable of destroying a local farmers entire year’s harvest in a surprisingly short amount of time. Simple fences made entirely out of chilies have proven to be extremely successful in repelling the strongest and most sensitive nose in the animal kingdom. These are just two examples of how cheap and simple solutions can be discovered and implemented in order to live near large wildlife with minimal threat to human life, crops, or cattle. Perhaps the real issue here, is how do we as humans around the globe learn to coexist with large wildlife and accept their existence and the benefits that they bring to the environments that they inhabit, rather than drive them to extinction wherever we go.

There are a number of good reasons why hippos should not remain in Colombia. However, a case can certainly be made for delaying their removal until more serious studies have been made regarding their long term positive or negative effects on the Colombian environment. Unfortunately, the management options for the hippos are stark, either kill the entire herd or let them be. Importantly, the case of the Colombian hippos raises ecological, philosophical and ethical dilemmas. Perhaps rather than racing to remove them through ethically challenging but ecologically justifiable lethal means (such as culling) we should linger on these dilemmas. For example, how is our relationship with the environment evolving? How do we coexist with wildlife as natural spaces on earth disappear and accelerate extinctions in the age of the Anthropocene? And what actions does this evolving relationship with nature require of us? More specifically to the hippos, if killing the hippos is socially unacceptable and studies show that the ecological benefits of the hippos balance out their negative impacts, then perhaps humans, hippos, and the wilderness of Colombia can coexist.