Terror birds bone (IMAGE) Johns Hopkins Medicine Caption The end of a terror bird’s left tibiotarsus, a lower leg bone in birds equivalent to that of a human tibia or shin bone, dates back to the Miocene epoch around 12 million years ago. Credit Degrange et al. Usage Restrictions none License Original 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.