A strong conical shell protects it from predators and its muscular foot grips to the rock regardless of the strength of wave. Higher up the shore taller, wider limpet shells allow for greater water retention when exposed by the falling tide. Limpets travel slowly, grazing rocks of microscopic algae with a rasp-like 'radula' or toothed tongue. They follow a trail of mucus left and return to the same spot or 'home scar' after every excursion. This scar is a ring which the limpet gradually grinds into their anchor spot on the rock, to aid their grip and help them retain water.
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