Fig. 4. The mean frequency of freezing behaviour recorded during 20 min of observations on the reflective and non-reflective sides (matte) of the test aquarium. Dominant and subordinate crayfish paired for 3 days froze more frequently on the mirrored side of the tank. After 3 days of pairing, dominant and subordinate crayfish also froze more in the reflective environment as opposed to the non-reflective environment (paired t-test: ^***P<0.0001, ^**P<0.005, ^*P<0.05; N=20). Error bars depict standard deviation.