Figure 2. A putative sleep-like state with chromatophore activity (CA) in the cuttlefish Sepia officinalis.

Video still frames from a representative adult/senescent cuttlefish exhibiting changing chromatophore activity during quiescence. These 4 frames show 10 second, sequential frames beginning with quiescence (0:00) and 30 seconds of the sleep-like state+CA. The camera was positioned vertically over the animal, resting on the gravel bed; the front of the animal is pointed towards the upper right corner. Changes in chromatophore components include a darkening of the body and a disappearance of a white eye-bar (0:00–0:10), a lightening of the body, the appearance of a white square (0:10–0:20) and a subsequent disappearance of the white square (0:20–0:30). Body color components as defined as described by Hanlon et al [20]. See supporting information (Videos S1,S2) for representative videos of this sleep-like state+CA.