Biomechanical Model (IMAGE) American Museum of Natural History Caption Digital model of the skull of Leptarctus primus, showing reconstructed jaw muscle groups in red, yellow, and pink. The virtual muscles were activated in bite simulations to test the biomechanical capability of this extinct weasel relative. Credit © J. Tseng Usage Restrictions Can be used with appropriate credit 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.