When cocaine kingpin Pablo 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.
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 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. MORE
Header image: Introduced herbivores share many key ecological traits with extinct species across the world. Credit: University of Kansas/Oscar Sanisidro.