Talitrus saltator lives in a narrow band of damp sand and must return to it after foraging. Displacement experiments show the animals orient along the shore-normal axis characteristic of their home beach, rather than simply moving downhill or toward moisture, and they do so even when released on unfamiliar ground.
By day the sun serves as the reference, with a circadian clock compensating for its changing azimuth. At night the moon takes over. Because the moon rises roughly fifty minutes later each day, using it as a compass requires a separate timing system running on a lunar schedule, and behavioural work indicates sand hoppers possess exactly that. Shifting the apparent position of the moon with mirrors predictably rotates their headings.
The compass is not the only cue. Beach slope, sand moisture, wave sound and the polarisation pattern of the sky all contribute, and the relative weighting shifts with conditions. Populations from different beaches also inherit different preferred escape directions, matching their own local coastline orientation.