New York, March 24 (IANS): If you are in awe with Narcos and their dazzling yet dangerous escapades cocaine kingpin Pablo Escobar, love his hippos too as those animals may help counteract a legacy of extinctions, say researchers.

When Escobar was shot dead in 1993, the four hippos he brought to his private zoo in Colombia were left behind in a pond on his ranch.

Since then, their numbers have grown to an estimated 80-100, and the giant herbivores have made their way into the country's rivers.

Scientists and the public alike have viewed Escobar's hippos as invasive pests that by no rights should run wild on the South American continent.

However, a new study published in Proceedings of the National Academy of Sciences by an international group of researchers challenges this view.

Through a worldwide analysis comparing the ecological traits of introduced herbivores like Escobar's hippos to those of the past, they reveal that such introductions restore many important traits that have been lost for thousands of years.

"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 John Rowan from the University of Massachusetts Amherst.

"While hippos don't perfectly replace any one extinct species, they restore parts of important ecologies across several species," Rowan added.

While human impacts have caused the extinction of several large mammals over the last 100,000 years, humans have since introduced numerous species, inadvertently rewilding many parts of the world such as South America, where giant llamas once roamed, and North America, where the flat-headed peccary could once be found from New York to California.

The authors note that what most conservation biologists and ecologists think of as the modern 'natural' world is very different than it was for the last 45 million years.

Even recently, rhino-sized wombat-relatives called diprotodons, tank-like armored glyptodons and two-story tall sloths ruled the world.

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 researchers found that by introducing species across the world, humans restored lost ecological traits to many ecosystems; making the world more similar to the pre-extinction Late Pleistocene and counteracting a legacy of extinctions.

When looking beyond the past few hundred years - to a time before widespread human caused pre-historic extinctions - introduced herbivores make the world more similar to the pre-extinction past, bringing with them broader biodiversity benefits, the authors wrote.