November 12, 2008—For male fiddler crabs, the appearance of strength might be just as good as strength itself, a new study finds.

The tiny crustaceans (a male, above), which live in mangrove swamps and mudflats throughout the world, sometimes lose their claws during fights with rival males.

The crabs grow replacement claws that are much flimsier than the originals—but still appear intimidating to males and alluring to females. During courtship, the wave of a fiddler crab claw resembles violin playing, hence their name.

(Related photo: "She-Crabs Are World's Pickiest Daters" [August 4, 2005].)

The new research shows that "male performance traits, such as claw strength … are likely the key to success in male combat," said lead study author Simon Lailvaux, a biologist at the University of New South Wales in Australia.

That means "the males will pretend to be good performers even if they are not."

Work is ongoing at the Australian National University in Canberra to determine whether fiddler crabs that more easily lose their original claws—and grow new, larger ones—actually survive longer or father more young, Lailvaux added.

The study appeared this week in the journal Functional Ecology.

—Anne Minard