By studying 19 groups of Cenozoic mammals Charles Marshall and Tiago Quental tested and confirmed the Red Queen hypothesis. Red Queen is the hypothesis that states that groups must continue to adapt and evolve in response to their environments in order to survive. It’s not just extinction events that threaten groups–it’s also low rates of origination of new species. The new research (published in Science) shows that these mammal groups have experienced diversity declines in part due to their failure to keep pace with their deteriorating environments.