The class Cephalopoda, in the phylum Mollusca includes cuttlefish, octopus, squid and the nautilus. Cephalopods can change the color and texture of their skin in order to communicate between themselves, capture prey and avoid predators through camouflage. Chromatophores are cells in their skin that allow them to change color in a fraction of a second and express yellow, orange, brown, red, blue and black. Each cell is connected to an individual nerve controlled by the nervous system. When the muscles around each cell contract the pigment sac widens and more color is visible.