Researchers have built a robot crab that can compete in claw-waving displays with real fiddler crabs, but "Wavy Dave" doesn't always come out unscathed.

Wavy Dave the robot crustacean has been showing scientists how male fiddler crabs respond when they see a fellow crab waving. Famous for their enormous claws, the team made Wavy Dave blend in by giving him a huge claw of his own,

Scientists at the University of Exeter have created a robotic crab, nicknamed Wavy Dave, to understand how male fiddler crabs compete in claw-waving contests.