What killed the megafauna? The study's findings suggest that decreasing hemispheric temperatures and associated ecological changes were the primary drivers of the Late Quaternary megafauna extinctions in North America. Credit: Hans Sell Human activities and population growth have wrought much destruction to life on Earth. But when it comes to megafauna extinctions, evidence suggests we may be off the hook – rather, the major culprit could be climate change. In Australia, Cosmos recently reported a fossil discovery that revealed giant birds, reptiles and marsupials died out 40,000 years ago due to extreme climatic conditions and environmental degradation. Across the Pacific, a new study published in the journal