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 Crab Crashes Mating Season — and the Results Are Hilarious and Revealing
During mating season on the muddy shores of southern Portugal, fiddler crabs (Afruca tangeri) engage in intense waving battles — and this year, an unexpected challenger entered the ring: a robot crab nicknamed “Wavy Dave.”
Created by researchers to mimic real crab behavior, Wavy Dave was designed to study how male crabs react to rivals during courtship. In fiddler crab society, males wave their oversized claw in rhythmic displays to impress females and ward off other males. It’s a high-stakes contest — the winner may earn the chance to mate.
But Wavy Dave didn’t exactly blend in.
“The females realized he was a bit odd, and some of the males tried to fight him,” said lead author Joe Wilde, an ecologist and statistician at Biomathematics and Statistics Scotland.
In one showdown, a particularly aggressive crab even ripped off Wavy Dave’s claw, forcing the team to reboot and abandon that trial.
Still, the robot proved convincing enough to reveal some fascinating insights. The research, published August 6 in Proceedings of the Royal Society B, explored how male crabs adjust their behavior based not just on a rival’s presence, but on how that rival signals.
Key findings included:
- Males were more aggressive (less likely to retreat) when Wavy Dave’s claw was smaller than their own — suggesting they sized him up and saw a chance to win.
- Conversely, fewer crabs challenged the robot when it had a larger claw, possibly avoiding a fight they couldn’t win.
- Males invested more in their displays when they had a better shot at attracting a mate.
“Our findings reveal the subtle ways in which these crabs adjust their behavior to compete in a dynamic environment,” Wilde explained. “Just like businesses adjusting prices to beat competitors, male crabs tailor their efforts depending on what their rivals are doing.”
Despite losing a claw, Wavy Dave helped scientists understand the strategic decisions these tiny creatures make during courtship battles — and offered a few laughs along the way.