Nature Note #203: Fiddlers on the Move
Few animals are as synonymous with the ocean than the crab, ranging in size from the monstrous king crab of Deadliest Catch fame to the minute hermit crab, a favorite childhood and classroom pet. The most enigmatic can be found in the salt marshes of Bogue Sound and is easily recognized by their diminutive size and asymmetrically large claw; the fiddler crab. Of the six species of fiddler crab that can be found along the Atlantic coast line, we have three species: the Atlantic sand fiddler (Uca pugilator), the Atlantic marsh fiddler (U. pugnax), and the red-jointed fiddler (U. minax).
Their name derives from the large claw of the males either in reference its overall size or due to their tendency to move it back and forth like a bow across the strings of the fiddle. In fact, their mating display involves the males waving their large claw back and forth in a bid to attract females.
Given my inexperience with identifying crabs, I would have to say that these little ones were either sand fiddlers or marsh fiddlers as both look fairly similar to one another. Regardless of their identity, they are an adorable sight to see. I see them most often at low tide scampering away from my shadow as I pass by, worried they might be picked off as a meal. They tend to stick together in large groups, moving together as a scuttling, swarming mass of bodies and claws.
When I observed them, they seemed less interested in mating and more in consuming the detritus of the salt marsh mud. Detritus, for the uninitiated, is the collective term for rotting organic material, soil, and minerals present at the bottom of every garden bed, stream bottom, and forest floor all over the world and is the chosen food of detritivores. Animals like earthworms, earwigs, and many other invertebrates represent classic examples of detritivores. In a salt marsh, that role is filled by fiddler crabs. They are a massive benefit to the marsh for two reasons. As colonial animals, it is thought that their habit of burrowing into the substrate below and near the marsh helps to aerate the soil. In addition, fiddler crabs consume large amounts of waste materials and help to reduce the buildup of those decaying materials.
What is truly fascinating is how often people see these tiny animals and think so little of them. It's as if they are too small to take notice of them and are therefore unimportant. It's important to remember that in a system, it isn't the biggest players that hold sway. As Aldo Leopold once put it, "To keep every cog and wheel is the first precaution of intelligent tinkering." It's all the little pieces in between, working on their own little things, that help make the whole system work. Maybe we can all take a closer look at those little creatures we take for granted and spend some time appreciating all that they do. It's the least we can do.
Their name derives from the large claw of the males either in reference its overall size or due to their tendency to move it back and forth like a bow across the strings of the fiddle. In fact, their mating display involves the males waving their large claw back and forth in a bid to attract females.
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| Fiddlers on the move. Photo by me. |
Given my inexperience with identifying crabs, I would have to say that these little ones were either sand fiddlers or marsh fiddlers as both look fairly similar to one another. Regardless of their identity, they are an adorable sight to see. I see them most often at low tide scampering away from my shadow as I pass by, worried they might be picked off as a meal. They tend to stick together in large groups, moving together as a scuttling, swarming mass of bodies and claws.
When I observed them, they seemed less interested in mating and more in consuming the detritus of the salt marsh mud. Detritus, for the uninitiated, is the collective term for rotting organic material, soil, and minerals present at the bottom of every garden bed, stream bottom, and forest floor all over the world and is the chosen food of detritivores. Animals like earthworms, earwigs, and many other invertebrates represent classic examples of detritivores. In a salt marsh, that role is filled by fiddler crabs. They are a massive benefit to the marsh for two reasons. As colonial animals, it is thought that their habit of burrowing into the substrate below and near the marsh helps to aerate the soil. In addition, fiddler crabs consume large amounts of waste materials and help to reduce the buildup of those decaying materials.
 |
| A little gathering in the grass. Photo by me. |
What is truly fascinating is how often people see these tiny animals and think so little of them. It's as if they are too small to take notice of them and are therefore unimportant. It's important to remember that in a system, it isn't the biggest players that hold sway. As Aldo Leopold once put it, "To keep every cog and wheel is the first precaution of intelligent tinkering." It's all the little pieces in between, working on their own little things, that help make the whole system work. Maybe we can all take a closer look at those little creatures we take for granted and spend some time appreciating all that they do. It's the least we can do.
"It may not be irrelevant to note that even very modest forms of life, like earthworms, dung beetles, and fiddler crabs, have no trouble identifying the real problems they must deal with if they are to survive." - Edward Goldsmith
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