Rock Springtail Anurida maritima
At low tide hundreds of rock springtails wander down the beach searching for food, returning to the shelter of their rock crevices an hour before the tide turns. Vast numbers of them squeeze together in the fissures to avoid being immersed at high tide. It is here that they molt and lay their eggs safe from submersion and many of their predators.
Rock springtails are blue-gray in color with segmented bodies that are wider at the posterior end. They have three pairs of appendages used for locomotion, which also allow them to swarm over the surface of calm rock pools without sinking—they cannot swim. Springtails are so named for their jumping organ, called the furcula, which acts like a spring, propelling the animal upward if threatened. Unlike other springtails, however, the rock springtail does not have this feature.