Beastfile · Marine Life

Cuttlefish

Sepia officinalis

Also known as Common Cuttlefish

It puts on the best color display in the ocean and probably cannot see color.

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Overview

A cuttlefish changes the color, pattern and texture of its skin faster than anything else alive, running millions of pigment cells over layers of reflective ones. It uses this to vanish against sand, to send a rippling wave of dark bands down its body while hunting, and in some species to show courtship colors on one flank and female coloring on the other at the same time. The catch is that it has one visual pigment, so by the usual definition it is color-blind. How an animal that cannot see color matches it so precisely is unresolved; the leading idea involves reading color from the blur its odd W-shaped pupil creates.

Close view of a cuttlefish showing its W-shaped pupil and fin skirt

Origin

Coastal waters of the eastern Atlantic, North Sea, Mediterranean and Baltic, over sand and seagrass in relatively shallow water.

Habitat

Ocean

Notable Traits

•Changes color, pattern and skin texture in under a second
•A single visual pigment, so effectively color-blind
•W-shaped pupil, unlike almost anything else
•An internal cuttlebone used to control buoyancy
•Can display courtship and female coloring on opposite flanks at once

Conservation

Near Threatened in parts of its range and heavily fished, particularly in the Mediterranean and the eastern Atlantic. Short lifespans mean populations swing hard year to year.