Gray Wolf in Yellowstone National Park (image) Wildlife Conservation Society Caption This is a gray wolf in Yellowstone National Park. Gray wolves are one of the world's most widely distributed mammals and the most studied large carnivore. Credit Jeff Burrell Usage Restrictions For use in reporting this story only 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.