Daily colour changes associated with the fiddler crab, Uca capricornis

The purpose of this experiment was to examine the daily colour changes in relation to the tidal cycle in the fiddler crab, Uca capricornis. Experiments were conducted in the East Point Reserve, Darwin from Nov - Jan (04/05 & 05/06). Twenty-seven crabs (13 males, 14 females) were observed on the day after spring tide over several semilunar cycles. Digital photos of the crabs were taken before, during and after low tide. These photographs were examined for any changes in colour or pattern. Uca capricornis do not regularly change their colouration over the course of the day. Of the 27 individuals observed, 24 did not noticeably change their colour, and none altered their pattern.