Pharaoh cuttlefish often show a solid color when resting on a solid color background, alternating from a pale white to all dark brown. Additionally, they can show a mottled white and brown color, with a center circle of brown. The mechanism for color in the Pharaoh cuttlefish is about the same as it is in other cuttlefish. This color-changing function is produced by groups of red, yellow, brown, and black pigmented chromatophores above a layer of reflective blue and green tinted iridophores and leucophores, with up to 200 of these specialized pigment cells per square millimeter. These sacs of color are controlled by rings of muscle around the sac. The cuttlefish expands and contracts these muscle rings in order to show different colors.