Do Octopuses Have Ink?

Yes, most octopuses possess an ink sac located near the anus that produces a dark fluid, which is forcibly ejected through a funnel organ. The fluid, or the ink, also contains mucus, most of which is likely produced from a gland in the funnel organ. The ink is dark because it has melanin, the same pigment that gives human hair and skin their color. The presence of melanin in the ink highlights the complex biochemical processes that occur within the octopus’s body.

The ink sac is part of an octopus’s defense mechanism. When an octopus feels threatened, it ejects the ink to create a visual screen to confuse predators and conceal the octopus. The ink produced by some species can potentially paralyze the sensory organs of the attacker, thus aiding in the octopus’s survival. The ejection process is a coordinated effort involving the contraction of muscles around the sac. This level of control is indicative of the octopus’s advanced nervous system and its capacity for complex behaviors. People have found various uses of octopus ink in traditional remedies, as a natural food coloring, and more recently as a source of compounds being studied for modern medicines.