Horse (IMAGE) U.S. National Science Foundation Caption Evidence of thong bridle use suggests horses may have been ridden as early as 5,500 years ago. Credit Illustration by Sandra Olsen, Carnegie Museum of Natural History Usage Restrictions None License Licensed content 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.