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 tool-using and meat-eating human ancestors getting most of the blame.

A new study, led by J. Tyler Faith of the Natural History Museum of Utah and the Department of Anthropology at the U, 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.

Read the full press release here.

Video based on:

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. (DOI: 10.1126/science.aau2728)

**Banner image: Artist Heinrich Harder’s illustration of an extinct species of Moeritherium, an ancient ancestor to modern-day elephants. He completed the illustrations in the early 1900s. Credit: Heinrich Harder.