Editing Fiddler crab (section)

{{Short description|Genus of crabs}}
{{Redirect|Uca|other uses|UCA (disambiguation)}}
{{Paraphyletic group
| fossil_range = [[Early Miocene]]-recent<ref>{{cite web |title=''Uca Leach'' 1814 (fiddler crab) |url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=22745&is_real_user=1 |website=PBDB}}</ref>
| image = fiddler crab.jpg
| image_caption = [[Minuca minax|Red-jointed fiddler crab (''Minuca minax'')]]
| auto = yes
| parent = Ocypodidae
| includes =
* [[Gelasiminae]] <small>Miers, 1886</small>
* Ucinae <small>Dana, 1851</small>
}}

The '''fiddler crab''' or '''calling crab''' can be one of the hundred species of semiterrestrial marine [[crabs]] in the family [[Ocypodidae]].<ref name=Rosenberg2019/> These crabs are well known for their extreme sexual dimorphism, where the male crabs have a major claw significantly larger than their minor claw, whilst females claws are both the same size.<ref>Levinton, J. S., Judge, M. L. & Kurdziel, J. P. (1995) Functional differences between the major and minor claws of fiddler crabs (Uca, family Ocypodidae, order Decapoda, Subphylum Crustacea): A result of selection or developmental constraint? ''Journal of Experimental Marine Biology and Ecology, 193''(1-2), 147-160. [https://doi.org/10.1016/0022-0981(95)00115-8 doi: 10.1016/0022-0981(95)00115-8]</ref> The name fiddler crab comes from the appearance of their small and large claw together, looking similar to a fiddle.

A smaller number of [[ghost crab]] and [[mangrove crab]] species are also found in the family Ocypodidae. This entire group is composed of small crabs, the largest being ''Afruca tangeri'' which is slightly over two inches (5&nbsp;cm) across. Fiddler crabs are found along sea beaches and brackish intertidal mud flats, lagoons, swamps, and various other types of brackish or salt-water [[wetlands]]. Whilst fiddler crabs are currently split into two subfamilies of [[Gelasiminae]] and Ucinae, there is still phylogenetic and taxonomical debate as to whether the movement from the overall genus of ‘’Uca’’ to these subfamilies and the separate 11 genera<ref name=Rosenberg2019/>

Like all crabs, fiddler crabs [[molting|shed their shells]] as they grow. If they have lost legs or claws during their present growth cycle, a new one will be present when they molt. If the major claw is lost, males will regenerate one on the same side after their next molt.<ref>Weis, J. S. (2019). On the Other Hand: The Myth of Fiddler Crab Claw Reversal. ''BioScience, 69''(4), 244-246. [https://doi.org/10.1093/biosci/biz011 doi: 10.1093/biosci/biz011]</ref> Newly molted crabs are very vulnerable because of their soft shells. They are reclusive and hide until the new shell hardens.

In a [[controlled experiment|controlled laboratory setting]], fiddler crabs exhibit a constant [[circadian rhythm]] that mimics the ebb and flow of the tides: they turn dark during the day and light at night.<ref>{{Cite web |title=Elements of Ecology |url=https://www.pearson.com/en-us/subject-catalog/p/elements-of-ecology/P200000006836/9780137502165 |access-date=2024-12-11 |website=www.pearson.com}}</ref>