Fiddler crab 9 subgenera: Fiddler crabs are occasionally kept as pets. The fiddler crabs sold in pet stores generally come from brackish water lagoons. Because they live in lower salinity water, pet stores may call them fresh-water crabs, but they cannot survive indefinitely in fresh water. Fiddler crab A fiddler crab, sometimes known as a "calling crab", may be any of approximately 100 species of semi-terrestrial marine crabs which make up the genus Uca. As members of the family Ocypodidae, fiddler crabs are most closely related to the ghost crabs of the genus "Ocypode". This entire group is composed of small crabs
Wall spider called "O. annulipes"). One species of interest is Oecobius civitas. When a spider enters the home of another spider, rather than defend itself, the resident leaves to find another one. Wall spider Wall spider is the common name for members of the genus Oecobius. The members of these several species are all very small spiders that make small flat webs over crevices in walls and in similar spaces. They possess an organ called a cribellum, which is a kind of comb-like device used to separate fibers of silk drawn from its spinnerets into many extremely fine fibers. Those fibers are