Defense mechanism: "Calappa, when seized, often draws up its legs under the broad shields formed by the overlapping edges of the carapace, thus seeming to sham death. No doubt it is more difficult to dismember in this attitude, but it is quite possible that the action has no such special significance in this case, being instinctively adopted whenever the animal is moved against its will. The colouring of many Calappidae is another feature in which they are adapted to their environment, being sand-like, and clearly protective."
Calappa are usually more active than other sand crabs. (Borradaile, 1903)
"Dredged in Felidu, Haddumati and Suvadiva Atolls in 25 — 43 fathoms." (Borradaile, 1903)
Inhabit sandy areas. (Borradaile, 1903)
Respiration: From their concealment in the sand, they create breathing channels to the surface of the sand. "The Calappidae draw in water, like many other crabs, down a passage formed, so to speak, by 'holding the hands against the breast,' and so into the gill-chamber through an opening in front of the chelipeds, guarded by the wide base of the epipodites of the third pair of maxillipeds. But their hands (chelae) are peculiarly shaped for this purpose, being very broad and flat, and usually having a toothed crest, which is held against the forepart of the body. Through the notches between the teeth water can enter, while at least the coarser sand-grains are kept out." (Borradaile, 1903)
Basic mode of nutrient uptake is heterotrophy.
"Judging from the contents of their stomachs, de Haan came to the conclusion that Calappa... feed on other crabs." (Borradaile, 1903)
Calappa gallus, common name rough box crab,[1] or lumpy box crab,[2] and Hawaiian name poki poki,[2] is a benthic species of box crab in the family Calappidae.[1]
Calappa gallus, common name rough box crab, or lumpy box crab, and Hawaiian name poki poki, is a benthic species of box crab in the family Calappidae.
