The infamous drug lord Pablo Escobar has left behind a zoo full of wild animals in his grandiose Hacienda Nápoles estate at Medellín.
Among lions, giraffes and other exotic wildlife species - he preserved hippos, an animal which is widely known as unfavourable towards nature and now thriving in the small lakes of northern Colombia as world's largest invasive animals, reported The Guardian.
Now scientists say that contrary to the conventional wisdom that large invasive herbivore mammals have strictly negative effects on their new environments, Escobar's "cocaine" hippos show how introduced species can restore a lost world.
A team of conservation biologists has compared the traits and impacts on the ecosystems of the Colombian hippo with their extinct counterparts like mammoths, giants sloths and giant wombats. Their contribution in the ecosystem was not seen because of human's activity of widespread extinctions of megafauna.
Their new study, published in Proceedings of the National Academy of Sciences, found that some introduced herbivore species are an almost perfect ecological match for extinct species from the Late Pleistocene, such as modern day wild horses known as mustangs and the extinct pre-domestic horses in North America, while others bring back a mixture of traits.
"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 notoungulata – shares with hippos large size and semiaquatic habitats," explained study co-author John Rowan, Darwin fellow in organismic and evolutionary biology at the University of Massachusetts Amherst.
"So, while hippos don't perfectly replace any one extinct species, they restore parts of important ecologies across several species."
By comparing ecological traits such as size, food habit, livelihood of these hippos with their predecessors - researchers have found similarities between these two.
The analysis found that by introducing large herbivore species across the world, humans had restored lost ecological traits to many ecosystems, thereby counteracting a legacy of extinctions and making the world more like the pre-extinction late Pleistocene.
Erick Lundgren, lead author and PhD student at the University of Technology Sydney said "The word 'invasive' doesn't really leave any room for organisms that do something that's beneficial for another species. 'Invaders' don't really help anything. And with that kind of anthropomorphic branding, you end up with a very limited range of research questions that are usually asked."
He gave an example of farmers across the southern US don't like pigs for always rooting for food. But he explained that's also a kind of behavious which serves the eco system in turn.
"There are many species that did what pigs do: just turning over soil. In North America, there were these giant peccaries. There were all these species that did the same thing in the late Pleistocene. For millions of years, everything evolved with this kind of rooting behaviour," he explained.