Facial Musculatures (IMAGE) Proceedings of the National Academy of Sciences Caption Facial musculature in the dog (left) and wolf (right) with anatomical differences highlighted in red. Credit Image courtesy of Tim Smith (artist). 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.