If you ever witness the movement style of a fiddler crab, there is absolutely no need to rub your eyes in utter confusion and befuddlement. Sideways moving is 100 percent normal and typical for these wee, semi-terrestrial crustaceans. In fact, moving in any other way would actually be bizarre.
Do Fiddler Crabs Always Move Sideways?
Fiddler crabs indeed always move sideways, according to the Gulf Coast Research Laboratory of the University of Southern Mississippi. In fact, backward and forward motions simply do not exist for the crab species. Fiddler crabs, despite their sideways movements, are known for their speedy "running" capabilities.
Intimidation and Running
If you are ever in the vicinity of any fiddler crabs, you may notice that they typically start to move rather swiftly when they feel frightened or intimidated in any manner. The crabs create burrows and use them as safe havens. If they feel that a predator is nearby, they will retreat into the burrows until the menace is completely gone. Once the danger is totally out the picture, fiddler crabs then emerge from their burrows .
Sideways Running and Mating
Rapid sideways running in fiddler crabs isn't always just a way to get out of harm's way. It also is a major component of their mating rituals. In the world of fiddler crabs, the females are the ones to initiate mating relations. Female fiddler crabs gaze directly at the males, which then typically prompts the males to quickly move over to them. After moving toward the female fiddler crabs, the males then immediately return to their burrows. This is the cue to the females to tag along. Once the females do indeed make way to the burrows, mating begins.
Fiddler crabs can be rather aggressive and fight-happy creatures amongst each other, but often unite during feeding time. During times of feeding, spectators may observe the little crabs traveling around "en masse" -- often in clusters of thousands and thousands. If you happen to spot a seemingly countless amount of crabs moving sideways around a salt marsh, then you probably know exactly what time it is!
- Texas Parks & Wildlife: Fiddler Crab
- The University of Southern Mississippi Gulf Coast Research Laboratory: Fiddler Crabs
- Alabama Coastal Fishing: Fiddler Crab
- University of Rhode Island Environmental Data Center: Fiddler Crabs
- South Carolina Department of Natural Resources: Fiddler Crabs
- Chesapeake Bay Program: Fiddler Crabs