Wolves Prowling (image) S.J. & Jessie E. Quinney College of Natural Resources, Utah State University Share Print E-Mail Caption Wolves are often implicated as the top predator affecting prey populations. New research from Utah State University indicates that cougars are actually the main predator influencing the movement of elk across the winter range of northern Yellowstone National Park. Credit National Park Service Usage Restrictions None Share Print E-Mail 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.