Climate change responsible for rapid expansion of horse species over last 20 million years
(PHYSorg.com Archaeology & Fossils)

Changing environments and ecosystems were driving the evolution of horses over the past 20 million years. This is the main conclusion of a new study published in Science by a team of palaeontologists from Spain and Argentina. The team analysed 140 species of horses, most of them extinct, synthesising decades of research on the fossil history of this popular group of mammals.