Burrowing

Burrows

O. cordimanus excavates burrows within the extralittoral zone of sandy beaches (Rao 1968).  Burrow openings are plugged during hotter periods of the day (Moss and McPhee 2006). A fossorial lifestyle protects the animal from extremes of temperature and low humidity and reduces incidences of predation (Bellwood 2002). Burrows are mostly occupied by individuals but ghost crab burrows may be used for copulation (Hughes 1971). 

O. cordimanus exhibits two types of burrowing behaviour: burrowing and burying (Bellwood 2002; pers. obs.).  Burrowing to form a burrow is known as side-burrowing and this is performed when one set of walking legs scoops sediment and the opposing set of legs grips the substratum (Bellwood 2002). The chelipeds and second and third pereiopods of the opposing legs are used to collect the sediment and deposit it outside the burrow (Bellwood 2002). O. cordimanus is a prolific bioturbator and digs slightly curved, non-spiral burrows (Horch 1975). The excavation and maintenance of burrows provides an important ecosystem service on sandy beaches through the aeration, translocation and recycling of nutrients (Valero-Pacheco et al. 2007)  Burying occurs when the animal excavates the sediment until its body is concealed (Bellwood 2002). The depth of burial is shallow, from 10 to 50 mm and the buried body remains in contact with the  sediment (Bellwood 2002). 

Burrows can extend inland for up to 200 m from shore (Jones and Morgan 2002).  Juveniles of the species are less able to tolerate periods of dessication and are distributed closer to shoreline where they can renew water in gill chambers more frequently (Wolcott 1984)