Walking Sideways: The Remarkable World of Crabs

The world's nearly 7,000 species of crabs are immediately recognizable by their claws, sideways movement, stalked eyes, and thick outer shells. These common crustaceans are found internationally, thriving in various habitats from the edge of the sea to the depths of the ocean, in fresh water or on land. Despite having the same basic body type as decapod crustaceans—true crabs have heavy exoskeletons and ten limbs with front pincer claws—crabs come in an enormous variety of shapes and sizes,...