ScienceShot: Crabs Eavesdrop to Find Females

Hi there! When male fiddler crabs (Uca mjoebergi) see a female in the distance, they wave their huge, single claw enthusiastically up to 20 times to attract her. Now, a new study published online in Biology Letters has shown that males also resort to eavesdropping on their competitors to learn the whereabouts of potential mates. The researchers, who staged 50 courtship encounters, found that when a male crab viewed another male waving his courtship claw, he would begin to wave his own--even when he couldn't see the female himself. Eavesdropping gives crabs a claw-up in the mating world, the scientists conclude.