You Better Shop Around, Crab

How fiddler crabs pick their mates

IN THE CASE of fiddler crabs, it pays to be choosy when selecting a mate. Researcher Catherine DeRivera of Oregon's Aquatic Bioinvasions Research and Policy Institute discovered that female fiddler crabs visit as many as 100 male crabs' burrows before settling down. Female fiddler crabs that rush to pair off risk ending up in a burrow that is too large. A poorly sized burrow can lead to the crab couple's larvae being hatched and washed out to sea either too early or too late, when tidal conditions will carry them smack into the waiting mouths of predators.