The present study describes some activity patterns in the field and laboratory of five hermit crab species (_Calcinus latens, Clibanarius signatus, Clibanarius longitarsus, Diogenes costatus_and _Diogenes pallescens_) inhabiting an intertidal flat of mangrove swamp at Red Sea coast. The recorded activity patterns were clustering, scattering, locomotion, standing up at sediment surface with legs outside the shell, retracted into the shell, ... Read more