Researchers have long known that female fiddler crabs have a certain appreciation for the size of a mate’s claw, but new findings suggest that in at least one species, the design of the male’s pad is also important. John Christy, a staff scientist at the Smithsonian Tropical Research Institute, studied the courtship behavior of a particular species of fiddler crab in the intertidal waterways of Panama. The male fiddler crabs often build sand castles atop the entrance to their burrows. Flagging the young crab vixens down with their oversized “holla” claw, females were much more likely to accept the invitation of crabs with castles over those that did not. When dog kibble was spread around the area, “artificially increasing the risk of predation” by attracting shore birds, female fiddler crabs were even more likely to choose mates with fancy digs. Castle’s with velvet ropes blocking the entrance were sometimes observed letting in three or four female crabs at a time, while males were forced to wait outside and be devoured by shore birds.
Video of Uca terpsichores flagging down the honeys. Similar human behavior can be seen at the Jersey Shore.