A tiny robot fiddler crab is helping environmental scientists better understand the complexities of animal mating rituals and rivalries. The male fiddler crabs responded to Wavy Dave’s motions, but didn’t quicken their movements. Thus, Wavy Dave was born. Wilde and collaborators took Wavy Dave on a trip to the beaches of southern Portugal, where thousands of fiddler crabs live in oceanside mudflat burrows. They waited for the crustaceans to emerge, and recorded the interactions as Wavy Dave greeted them at various claw speeds.