Before I visited the Georgia Aquarium, most of what I used to know about cuttlefish included the fact that they can be purchased neatly packaged in dried chewy form in Japanese groceries. So, I was very surprised when I first met one face to face in the Georgia Aquarium and realized they are remarkably intelligent creatures.

Cuttlefish are invariably curious about people, and will come up and try to get a better look if you catch their eye. They are precision swimmers, able to hover motionless near an object of interest by rippling their skirt of fins, only to suddenly jet off in another direction using their funnel siphon when they have seen enough.

They are equally curious about other cuttlefish - even images of cuttlefish - as the video below by Brian Leahy demonstrates. In the middle of the video, the videographer turns the camera's display around to face the nearby cuttlefish which inspires an immediate darkening response, and causes all the other cuttlefish in the tank to start moving purposefully toward the camera.

An article by Brenna Lorenz describes an encounter with cuttlefish and humans who had the idea to match the gestures made by the cuttlefish with their tentacles. The Cuttlefish of Sentosa (Sentient Cephalopods), by Brenna Lorenz

The ability of cuttlefish to instantly mimic the color and texture of their environment, particularly the area underneath them, is well known but little understood. They use a layer of chromatophores and a layer of iridiphores (reflective cells) [Meet the Cuttlefish] which are revealed when chromatophores contract as well as detailed muscular control to create visual and textural illusions.

The textures and colors they imitate are so complex that it led me to wonder if cuttlefish use only their eyes as the sole inputs for processing visual information. In other words, if their eyes are covered, can they still mimic their surroundings? Several recent articles present evidence that their eyes are indeed the main sensors. Cuttlefish eyes have been determined to be colorblind, but are sensitive to the orientation of polarization of incoming light. One study determined that contrast is one of the main visual cues used to determine the pattern of camouflage.

Cuttlefish mimicking a net trap
(I don't have an attribution for this photo yet)

Their visual patterning is used for communication as well as camouflage, and even sometimes for hypnotizing their prey [ A Dazzling Show.]

These visual signals have been analyzed and found to have a signal capacity of approximately 3 bits per signal - enough for some primitive communication, if not an actual language in the human sense of the word.