Fig. 2. Example of a tail-flip response and response patterns for different shadows. (A) An example of a tail-flip response of a crayfish exposed to a slow shadow. Shown are (1) the animal in the start compartment shortly after the experiment was started, (2) the animal in the tunnel walking towards the food odor release point and approaching the bath electrodes, (3) the animal producing a tail-flip in response to the shadow and (4) the animal in its final position after completing the tail-flip. (B) Patterns of behavior in response to shadows of different velocities. The number of tail-flips decreases with increasing shadow velocity while the number of stops increases. The differences in response pattern are statistically significant (^*P0.01).