Purple Marsh Crab (image) Ecological Society of America Caption This shows a large male purple marsh crab (Sesarma reticulatum) clipping cordgrass with its claws. The burrow opening in the photograph leads to a large, communal burrow inhabited by 10-15 crabs. These crabs are nocturnal and typically reside in burrows during the day to stay moist and avoid predators. Credit Tyler Coverdale Usage Restrictions Include credit Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.