What triggered the decline and eventual extinction of many megaherbivores, the giant plant-eating mammals that roamed the Earth millions of years ago, has long been a mystery. These animals, which weighed 1,000kg or more and included the ancient relatives of modern elephants, rhinos, hippos and giraffes, reached a peak of diversity in Africa some 4.5m years ago during the Pliocene epoch (between 5.3m and 2.6m years ago). After this, their numbers slowly declined, in a trend that continued into the Pleistocene (2.6m years ago to roughly 11,000 years ago).
Both the Earth’s climate and hominins – our early human ancestors – have in the past been blamed for this change. However, a recent paper argued that the gradual extinction of megaherbivores occurred because of long-term environmental changes and that developments in hominin behaviour – such as wielding tools and using fire – did not impact megaherbivore decline.
While this seems to be true of the early decline in megaherbivore population, we argue that our ancient human ancestors may well still have contributed to more recent megaherbivore extinctions. What’s more, we’re repeating the pattern today. Read more at The Conversation.