Today, Africa has five species of massive, plant-eating mammals, the so-called megaherbivores: Elephants, hippos, giraffes, and white and black rhinos. Millions of years ago, however, there was a much greater diversity. When and why these species disappeared has long been a mystery for archaeologists and paleontologists, despite the evolution of tool-using and meat-eating hominins getting most of the blame.
New research disputes a long-held view that our earliest tool-bearing ancestors contributed to the demise of large mammals in Africa over the last several million years. Instead, the researchers argue that long-term environmental change drove the extinctions, mainly in the form of grassland expansion likely caused by falling atmospheric carbon dioxide levels.
Video based on:
J. Tyler Faith, John Rowan, Andrew Du, Paul L. Koch. 2018. Plio-Pleistocene decline of African megaherbivores: No evidence for ancient hominin impacts. Science. Nov. 23, 2018.