What Era Are We In?

The extinction of the dinosaurs gave mammals the chance to proliferate and fill most environmental niches. Birds have also thrived in the Cenozoic Era and outnumber mammals two to one. Grass has played an important role in the era and helped to shape the evolution of both mammals and birds. Much of the course of evolution has also been shaped by changing climate. Shifting continents caused changes in ocean currents that resulted in cooling for much of the Cenozoic Era.