To show of there claws and impress females.
The males wave it over their heads to get the female's attenteion.While doing that it looks like their fiddling.Thats why there called fiddler crabs.
they eat humans fiddler crabs eat other smaller crabs
by rubbing their big claw on there body
Ghost crabs? Well that depense if it is a dead fiddler crab so it would be the same/
yes they are
no
== == == ==
?
no they are not
you kill the fiddler crab
fiddler crabs drink fresh water.
crabs are nocturnal