The sand scorpion Paruroctonus mesaensis is able to determine the distance to its prey . Experimental data shows that a sand scorpion, which has a diameter of 5 cm, can accurately determine distances up to 15 cm with an error of about 1 cm. For distances exceeding 15 cm, a scorpion must only move approximately 10 centimeters towards the source before receiving another cue. We have identified a mechanism that would allow a scorpion to match a unique pattern to each distance and developed a neuronal model that performs distance determination up to the precision needed. Generalization to other animals is considered.