Question: why and how do cuttlefish change colour ?!

Sarah-Jane Walsh answered on 24 Jun 2013:

Cuttlefish and other cephalopods such as octopus have special cells called chromataphores, these are pigmentation cells that display a certain colour. Cuttlefish have many layers of these cells stacked on top of each other and by activating different ones can rapidly change colour and pattern. The cells don’t actually change colour but over the cells is thin layers of muscle which when stretched go transparent so allow the colour underneath to become visible. These muscles are attached to nerves which are sent rapid signals from the Cuttlefishes brain, which is why the cuttlefish can change colour so rapidly.

Apart from chomatophore there are several other types of cells Iridophores make metallic colours, Leucophores are reflective white cells that appear in spots, and photophores hold chemicals that when mixed create light or bioluminescence!