Israel Journal of Ecology & Evolution, 2017 http://dx.doi.org/10.1163/22244662-06303002

The Case for Hippos in Jacob Dembitzer* University of Miami, United States

Abstract Drug lord imported 4 ( amphibius) onto his private estate in Colombia in the 1980s. Since his arrest and assassination, the hippos have escaped the confines of the property and have begun to reproduce in the wild of Colombia. They now number approximately 60 individuals. The presence of such a large, and possibly dangerous, species in a new habitat raises several moral and ecological questions and dilemmas. It is unknown what effect these animals may have on their new environment, or the threat that they pose to the people living near them. In an effort to mitigate possible risks to the environment and local populations the Colombian government initiated an effort to castrate all males in the herd. However, it is unlikely that these efforts will be very effective in curbing the population growth of the animals. South America lost most of its large species of animals during the Quaternary Extinction and it is possible that the hippos are filling a gap that still exists in the ecology of the continent. The rewilding efforts occurring around the world aim to restore and protect natural processes and habitats by introducing (or reintroducing) apex predators or keystone species. Perhaps further research could shed light on possible positive influences that the Hippos have on the South American environment and responsible ways to avoid risks to local populations.

Keywords Hippopotamus amphibius; compassionate conservation; Colombia; introduction; native

In the 1980s, the infamous drug lord Pablo Escobar im- Pablo, in the documentary “Los Hipopotamos del Capo.” ported 4 hippos onto his estate in Colombia. Today, the “The day that he moved into his ranch he had me order the hippos have escaped the estate and they number around 60 hippos from a zoo in the states and he was up all night on individual animals and continue to reproduce. To mitigate the radio checking to see that they were on their way and risk of harm to humans and curb hippo population growth, alright,” (Velez Dominguez, 2011). The drug lord ­imported the government has begun an effort to castrate the males 4 hippos, 1 male, and 3 females, to his private 7,000-acre in order to control their numbers. How effective are these ranch and zoo named “Hacienda Napoles.” Since the cap- efforts? Perhaps it is possible that leaving these hippos in ture and fall of Pablo Escobar in 1991, most of the animals Colombia may bring more benefits into the environment have been taken to zoos around Colombia. The hippos than harm, and allowing them to expand their population (Hippopotamus amphibius) however have been left to their and habitat may not be as bad of an idea as it sounds. In own devices due to their enormous size as well as the dif- addition, what moral questions do these hippos raise in a ficulties and dangers of transporting them. Today, their world where natural spaces grow ever smaller. numbers are estimated to be somewhere between 30 and It is vital to recognize the guiding principles of Com- 60 animals. With no natural predators, perfect climate, and passionate Conservation when considering how a country unlimited space to roam the population of these “foreign- should handle such an issue. These principles being: Do no ers” is showing no signs of getting smaller. harm, recognizing the importance of individual wild ani- Since the population explosion of the enormous Afri- mals, de-categorization of wild animals, and co-existence. can animal three options have arisen to control their num- When dealing with this issue, it is perhaps necessary to bers. Castration, control of the population in the ranch, and reconsider the categorization given to these animals as, killing them for their meat. However, each control option “pests,” or, “invasive,” while taking into account all possible seems to be fraught with difficulty. According to experts, options before causing unnecessary harm and suffering to hippo meat is dangerous since it may carry harmful dis- cognizant beings (Ramp, 2015). In a world that has changed eases (Howard, 2016). In addition, a government lead ef- beyond recognition over the last century, it is crucial to rec- fort to kill the hippos caused a large public outcry after ognize the option of co-existence when possible, and the a single individual was killed. This eventually ended the benefits it may bring (Lundgren, 2017;­W allach, 2015). idea of killing the remaining hippos. The local authorities “Pablo always loved animals. When he was very young then decided to implement the option of castration and re- he had a book with pictures of all the animals in the world location; however, this option is much more difficult than and he had an inexplicable obsession with the page on it sounds. In order for a hippo to be castrated, it must be ­hippos,” Recalls , the older brother of sedated while on land (because in the water they will very

*E-mail: [email protected]

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6 J. Dembitzer easily drown) and while they are alone so that other hippos Large wildlife is often considered “­umbrella species,” cannot attack. The nocturnal society of hippos and dense whose ability to exist depends entirely on the health of the herd lifestyle make this very difficult. Even if a bull is suc- eco system that they inhabit. Therefore, in protecting large cessfully found alone outside of water and the operation wildlife, an entire eco system is protected. If studies show can be performed another problem arises. Hippos are ex- that the hippos bring benefits to the Colombian wilderness, tremely sensitive to chemical changes in their body and then could that open the door to brave new projects around sedation can easily kill even a full-grown male (Kremer, the world for rewilding? 2014). A bull who has strayed far from the ranch must be In the case of hippos (the second largest land-animal in sedated, castrated in the field, and brought via helicopter the world) in the heart of Colombia, conservation experts back to the ranch; this process often happens in the pres- advise for their removal. They are deemed a threat to the ence of the Colombian army (Los Hipopotamos del Capo). local environment, native endangered species (specifically The entire process is extremely difficult and dangerous to giant otters and manatees), and human life. Hippopota- both the hippos as well as to the humans performing the muses within their native range in Africa are kept in check castration. Castration requires all of the males to be treat- due to the dry season which creates a significant shortage ed. If even one male is left without being castrated then the of food; in tropical Colombia where the dry season is not entire process will prove to be a failure as he will fertilize as harsh as it is in much of the hippos’ territory in Africa, it all of the females. In other words, castration may not be is believed that their populations can increase dramatically such a realistic option (Kremer, 2014). by 50% per year (Kremer, 2014). However, there are also Today, the presence of such giant creatures in Colom- natural populations of hippopotamus in The Democratic bia seems to be a bit far-fetched and unnatural. Howev- Republic of Congo which boasts the second largest rain- er, the Colombia of 15,000 years ago was very different forest in the world after the Amazon, and is, in fact, similar from the Colombia of today. The country was filled with to the damp Colombian climate that the invaders now call giant ground sloths that stood 6 meters high, several spe- home. It is difficult to say what would naturally keep the cies of elephant, large lamas, and of course saber tooth ti- population of these hippos in check since the number of gers. Shortly after the arrival of humans in the Americas hippos in the Democratic Republic of Congo have declined these ancient and giant species of “megafauna” could not by approximately 95% in recent years due to human activ- handle the burden of the human invaders and were soon ity and hunting (Lewison, 2007). This is more reason why enough hunted to extinction and wiped off the face of the a rewilding effort in Colombia could be essential to saving continent and planet (Barnosky, 2004; Bartlett, 2015; San- one of the most iconic species on earth. However, it also dom, 2014). These large species played a crucial role in means that more studies are necessary to investigate the shaping the environment that they lived in through seed full impact of hippos on such a lush environment. displacement and carrying nutrients over huge patches Hippos in Colombia might not be threatening to local of land. Since their disappearance, it is estimated that in species as automatically assumed. Hippos share many wa- some parts of the continent less than 1% of the nutrients ter ways in Africa with the same species that are present that used to be transferred across the surface of the con- in the rivers of Colombia. In several sub-Saharan coun- tinent are now transferred today by much smaller animals tries hippos live alongside otters and manatees (Jacques (Doughty, 2016; Mahli, 2016; Doughty, 2016). A new effort et al., 2015; Keith Diagne, 2015; Lewison and Pluháček, is being made around the world called “rewilding,” which 2017; WWF, 2017). aims to restore certain species that would have a similar There is no evidence that hippos have a negative effect effect in shaping the environment as locally large and ex- on the populations of these animals. In fact, the opposite tinct animals. There are a number of successful examples may be true. Hippos graze on land and then sleep in rivers of rewilding efforts with far-reaching consequences. The during the day, they release enormous amounts of nutrients reintroduction of wolves to Yellowstone national park into the rivers that they inhabit, which increases the amount which entirely reshaped the environment and ecology of of aquatic vegetation on which manatees feed but hippos the park. The wolves changed the behavior and habits of rarely do (Grey, 2002). Also, invertebrates and fish on the caribou which in turn impacted the vegetation struc- which otters eat. In ­addition, this process may bring up the ture and ­ultimately altered the course of the rivers in the numbers of black caiman which can, in turn, play a part in park. A Pleistocene park has already been built in Siberia. controlling the number of hippos by killing the young since Large animals such as muskoxen, wolves, lynx, reindeer, there is evidence showing that crocodiles possibly feed on and horses were reintroduced in order to investigate their young hippos in Africa (Kingdon, 1988; African Wildlife impact on the Siberian environment that these animals cre- Foundation, York, 2014). Studies have shown that hippos ate. Although the project is still only in its early stages, are a crucial part of maintaining fish populations and entire there are high hopes that the efforts will turn the frozen river food systems (Mosepele, 2009; Masese, 2015). tundra into grass steppe (Zimov, 2005). Plans are also The introduction of hippos may cause “eutrophication,” being made to restore elephants to their ancient Danish a sudden overabundance of previously unavailable nutrients stomping grounds (Gabbatis, 2006), and the idea was pro- and compounds leads to algal blooms (Howard, 2010). It is posed to build a massive megafaunal park with lions and an uncommon event (when driven by natural processes), elephants in the heart of the United States (Donlan, 2005; which usually occurs in lakes and not rivers. In addition, Donlan, 2006). These efforts may also reduce the threat of it is possible that the hippos may be carriers of parasites ­extinction that almost half the species on earth now face. or diseases native to Africa and not to Colombia. These

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Israel Journal of Ecology & Evolution 7 diseases could have enormous effects on the local species which are a cheap and simple set of lights that cover the of Colombia however as of yet there is no proof that the perimeter of a house or ranch that flash in sequence and hippos carry any foreign agents that could harm their new give lions and other large predators the impression of a environment. Cattle of all kind are also “invasive species” human guarding with a torch. Until now these lights have in Colombia causing endless destruction, but their pres- proven to be successful against lions and may also work ence near the is for the most part accepted. against other large animals. Another example would be An example of a mixed effect of a large exotic spe- chili fences. An elephant is capable of destroying a local cies on a new environment is the introduction of the Asian farmers entire year’s harvest in a surprisingly short amount water buffalo (Bubalus bubalis) to northern Australia in of time. Simple fences made entirely out of chilies have the nineteenth century. The buffaloes have many negative proven to be extremely successful in repelling the stron- effects on the environment such as soil erosion, displace- gest and most sensitive nose in the animal kingdom. These ment of many small vertebrates, vegetation loss, carrying are just two examples of how cheap and simple solutions infectious diseases such as tuberculosis, and a change in can be discovered and implemented in order to live near the chemistry of the water (Australian Department of Sus- large wildlife with minimal threat to human life, crops, or tainability, 2011). Despite these negative changes they also cattle. Perhaps the real issue here, is how do we as humans effected their environment in certain positive forms such around the globe learn to coexist with large wildlife and as increasing the growth rate of trees and reducing their accept their existence and the benefits that they bring to mortality rate across the buffalo habitat. The buffalo there- the environments that they inhabit, rather than drive them fore have a positive effect on the savannah environment to extinction wherever we go. of northern Australia (Werner, 2005). In addition, there is There are a number of good reasons why hippos should also evidence that the buffalo have a positive effect on the not remain in Colombia. However, a case can certainly be wetlands by replacing fires as a means of controlling the made for delaying their removal until more serious studies growth of grasses, and indirectly creating micro habitats have been made regarding their long term positive or nega- for amphibians and reptiles by trampling (Friend, 1990). tive effects on the Colombian environment. Unfortunately, In addition to the case of the water buffalo of Queensland the management options for the hippos are stark, either Australia there is also the case of feral Dromedary cam- kill the entire herd or let them be. Importantly, the case els (Camelus dromedarius). The camels which were intro- of the Colombian hippos raises ecological, philosophical duced in the early 20th century as porter animals proved and ethical dilemmas. Perhaps rather than racing to re- to be perfectly adapted to survive the harsh conditions of move them through ethically challenging but ecologically the outback desert in addition to their ability to digest over justifiable lethal means (such as culling) we should linger 80% of local vegetation. They fill a void in the Australian on these dilemmas. For example, how is our relationship habitat that was left by the extinction of megafauna (Lun- with the environment evolving? How do we coexist with dgren, 2017). However, with no major predators other than wildlife as natural spaces on earth disappear and acceler- dingoes which occasionally eat calves, their numbers have ate extinctions in the age of the Anthropocene? And what grown exponentially. Human-camel conflicts have arisen actions does this evolving relationship with nature require as camel’s number approximately 300,000 individuals of us? More specifically to the hippos, if killing the hippos (Deel, 2014) and cause severe damage to infrastructure, lo- is socially unacceptable and studies show that the ecologi- cal economies, and possibly the environment (Deel, 2014; cal benefits of the hippos balance out their negative im- Lamb, 2010). Their population is “managed” often with pacts, then perhaps humans, hippos, and the wilderness of brutal strategies such as ground or air culling. In contrast, ­Colombia can coexist. 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 References example of camels in Australia it is possible to see what African Wildlife Foundation. (2018). Hippopotamus. Re- happens when a large animal fills an ecological void that trieved from: http://www.awf.org/wildlife-conservation/ has not been filled for thousands of years. hippopotamus. 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