A cuttlefish uses chromatophores to change its skin color, just like other cephalopods. Each chromatophore contains a sac of colored ink that is surrounded by 15-25 muscles. These muscles are controlled directly by the brain, specifically the optic lobes (Hanlon and Messenger, 1987). This direct path from the chromatophores to the brain allows for rapid color change (less than 1 second) (Chiao et al., 2005). Cuttlefish also have two additional types of cells, iridophores and leucophores, that act as reflector cells (Barbosa et al., 2008). These cells help cuttlefish match background brightness. Once a cuttlefish has the visual input it needs, the brain sends a signal to the chromatophores, iridophores, and leucophores directing them what to do (Chiao et al., 2005). See Figure 1 for a flow chart of the process of camouflage in cuttlefish.

Visual input   Retina    Image Parameters  Local features  expression of pattern

Figure 2 (adapted from Kelman et. al, 2008). This figure shows the full process of expression of a camouflage pattern in cuttlefish. First the cuttlefish receives visual input via its retina. Then it detects image parameters such as luminance and spatial frequency. Then the cuttlefish detects local features including edges, object area, light regions, and depth. After it has identified these background features the cuttlefish determines the background type it is in. From this information the brain sends a signal to the chromatophores, iridophores, and leucophores telling them how to function and finally the most suitable body patterning is expressed.