Notorious drugs lord Pablo Escobar could be inadvertently helping save hippos from extinction, from beyond the grave.
When the cocaine kingpin was shot dead in late 1993, four hippos he brought to his private estate in Colombia were left to roam.
Since then, their numbers have grown to an estimated 80 to 100 and the hippos have made their way into the country’s rivers.
Scientists and locals have viewed Escobar’s hippos as invasive pests that should not be running wild on the South American continent.
But a new study, published in the journal Proceedings of the National Academy of Sciences, reveals Escobar’s hippos could be the saviour of the species.
Researchers conducted a worldwide analysis comparing ecological traits of introduced herbivores, such as Escobar’s hippos, to those of the past.
They found that such introductions restore many important traits that have been lost for thousands of years.
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Pictured: a vet preps one of Escobar’s hippos for dental treatment. The four original hippos now number around 80 to 100, and their presence has been criticised for having a detrimental effect on Colombian waters
64 per cent of introduced herbivores – such as hippos – are more similar to extinct species than to local native species, the study authors claim.
They may help restore a ‘lost world’ similar to pre-extinction times and counteract a legacy of extinctions by humans.
‘While we found that some introduced herbivores are perfect ecological matches for extinct ones, in others cases the introduced species represents a mix of traits seen in extinct species,’ said study co-author Dr John Rowan, of University of Massachusetts Amherst.
‘For example, the feral hippos in South America are similar in diet and body size to extinct giant llamas, while a bizarre type of extinct mammal – a notoungulate – shares with hippos large size and semiaquatic habitats.
Escobar bought four hippos from a zoo in California and flew them to his ranch in the early 1980s
‘So, while hippos don’t perfectly replace any one extinct species, they restore parts of important ecologies across several species.’
While human activity has caused the extinction of several large mammals over the last 100,000 years, the introduction of others has rewilded parts of the world, such as South America, where giant llamas once roamed.
Introduced herbivores make the world more similar to the pre-extinction past, bringing with them broader biodiversity benefits, the team say.
‘We usually think of nature as defined by the short period of time for which we have recorded history, but this is already long after strong and pervasive human influences,’ said study senior author Dr Arian Wallach at University of Technology Sydney (UTS).
‘Broadening our perspective to include the more evolutionary relevant past lets us ask more nuanced questions about introduced species and how they affect the world.’
The entrance gate to ‘Hacienda Napoles’. The airplane above the entrance was the first airplane Escobar used to smuggle cocaine
Even what can be termed as relatively recently, rhino-sized wombat-relatives called diprotodons, tank-like armoured glyptodons and two-story tall sloths ruled the world.
The researchers said that these giant herbivores began their evolutionary rise not long after the demise of the dinosaurs, but were abruptly driven extinct beginning around 100,000 years ago, most likely due to hunting and other pressures from our Late Pleistocene ancestors.
The Pleistocene Epoch is typically defined as the time period that began about 2.6 million years ago and lasted until about 11,700 years ago.
Pablo Escobar (pictured), who was shot dead by police in 1993, kept four hippos at his private menagerie at Hacienda Nápoles. They were left on the untended estate after his death
Lead author Erick Lundgren, a PhD student at UTS, says the possibility that introduced herbivores might restore lost ecological functions had been suggested but not ‘rigorously evaluated’.
To that end, the researchers compared key ecological traits of herbivore species from before the Late Pleistocene extinctions to the present day, such as body size, diet and habitat.
‘This allowed us to compare species that are not necessarily closely related to each other, but are similar in terms of how they affect ecosystems,’ said Lundgren.
‘By doing this, we could quantify the extent to which introduced species make the world more similar or dissimilar to the pre-extinction past.
‘Amazingly they make the world more similar.’
The introduced ‘surrogates’ for extinct species include evolutionary close species in some places, such as mustangs wild horses in North America, where pre-domestic horses of the same species lived but were driven extinct.
‘Many people are concerned about feral horses and donkeys in the American south west, because they aren’t known from the continent in historic times,’ Dr Rowan said.
‘But this view overlooks the fact that horses had been present in North America for over 50 million years – all major milestones of their evolution, including their origin, takes place here.
‘They only disappeared a few thousand years ago because of humans, meaning the North American ecosystems they have since been reintroduced to had co-evolved with horses for millions of years.’
