Header (IMAGE) Aarhus University Caption Prehistoric people are attacking an elephant. New research shows that humans and not the climate caused a sharp decline in almost all megafauna on Earth 50.000 years ago. Credit First printed in Bryant & Gay, 1883. Wood carving by E. Bayard. Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.