An Oceans Abcdarium created by the University of Applied Sciences in Mainz, Germany

Cephalopod Ink

Hanna Schuller

The iconic octopus is not the only animal that produces ink — other cephalopods like squids and cuttlefish share this mechanism of defense, along with sea hares, a marine snail. While the main component of this ink, the black pigment melanin, is mostly the same for all three, their individual colors differ: octopuses produce a neutral black ink; squid ink is blue-black; and the ink of cuttlefish is of a brown shade, known colloquially as sepia. In most species, two organs are involved in the ink’s production: the ink sac, and a mucus-producing gland. By varying the ratio of the two organ’s production, different shapes of ink can be produced: whether a diffuse cloud, a rope-like shape, or a form that roughly resembles a squid. Those so-called pseudomorphs are probably used as a decoy. The chemical composition of cephalopod ink is very complex and is not yet fully understood. A variety of mechanisms have been discussed, from sensory disruption to phagomimicry (ejecting a mixture of chemicals mimicking food, to overwhelm the senses of the predator). Traditionally used in cooking, it is also of pharmacological interest: some of its compounds have shown promising anti-inflammatory, anti-cancer, anti-Parkinson, immune boosting, and other interesting properties.

Sources: Derby, C.D., “Cephalopod Ink: Production, Chemistry, Functions and Applications”, Mar. Drugs, vol. 12, (2014): 2700-2730.

Tamilarasan, G. and Ramasubramaniam, “Study on Extraction of Cephalopod’s Ink for Dyeing of Textile Materials”, Global Journal of Engineering, Science and Research Management, (2019).

Sabry, Miral O., “Omar M. Sabry and Giovanni Caprioli: Intriguing diverse chemistry and unique molecular mechanisms: new medicines with diverse pharmacological activities from cephalopods ink”, Natural Product Research, (2022).