In spool and line technique for terrestrial snails, a spool of thread is glued to the shell of a snail so the thread unwinds as the snail moves, leaving a record of the movement pattern. Using spool and line to trace movement patterns of large (>13 mm diameter) land snails has distinct advantages over other methods of assessing movements in field studies including being relatively simple and inexpensive, giving a continuous record of animal positions and actual distances moved, ability to track many animals simultaneously, increasing the number of recaptures, being usable in dense cover and when the researcher is absent, and minimizing disturbance at recapture.