A Fiddler Crab Using a Crab Treadmill (IMAGE) University of Bristol Caption The researchers tested fiddler crabs using a crab treadmill that allowed the animals to walk naturally whilst being shown visual stimuli on a computer monitor. The crab would stop walking and freeze whenever it saw a stimulus Credit Sam Smithers, University of Bristol Usage Restrictions The image is for single use, should be credited and should not be archived 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.