Cuttlefish skin papilla morphology suggests a muscular hydrostatic function for rapid changeability.

Abstract in brief

• Cuttlefish skin papillae are specialized structures that allow rapid and dramatic changes in skin texture, functioning like muscular hydrostats similar to octopus arms, which provide both movement and support without rigid bones.
• The study found that these papillae are built from an extensive network of dermal erector muscles arranged in concentric rings and across the diameter, whose coordinated contraction causes the papillae to extend or retract by pushing tissue outward or pulling it inward.
• This muscular system not only enables quick physical changes for camouflage or signaling but also involves structural elements like light reflectors and chromatophores that produce visible color and pattern changes during extension and retraction.