Read the following passage carefully and answer the question.
Christmas Island Red Crab
Christmas Island Red Crab is an endemic land crab of Christmas Island. This species of crab can grow up to 116 millimeters wide. The male crab and the female crab have different sizes. The female crab is smaller in size than the male crab. However, the female adult crabs have bigger abdomens with smaller claws. These crabs are mostly red, just like their name. However, some of them can be orange even purple in color.
The statement of the phenomenon in the above text is....