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Atlantic Marsh Fiddler Crab

Minuca pugnax

An Atlantic Marsh Fiddler Crab standing on a rock

Max Size: 2.6 cm (carapace width) (~1 inch)

Habitat: Salt marshes, muddy and sandy shorelines, often near shoreline grasses like Spartina alterniflora

Diet: Algae, bacteria, fungus and dead/decaying plant and animal matter

Fun Facts:

  • Male fiddler crabs have one claw that is much larger than the other, while female fiddler crabs have two claws that are the same size.
  • Male fiddler crabs wave their larger claw to attract female fiddler crabs during mating season. They also use sound, produced through this claw movement and by stamping their walking legs.
  • Fiddler crabs are named for the males’ large claw, which resembles a fiddle when they bring their smaller claw to and from their mouth, like a fiddler drawing a bow across their instrument.
  • Fiddler crabs dig burrows to make nests, escape predators, gain relief from the heat and hibernate during the colder months of the year.
  • A male fiddler crab’s large claw can grow to nearly half of its total bodyweight – while larger claws offer an advantage during displays of aggression with other males, they also make it harder to burrow and feed.
  • By consuming detritus, fiddler crabs can increase the amount of nutrients available for marsh grasses.