ink
Quick Summary
Most octopuses have an ink sac that produces a dark fluid containing melanin, the same pigment found in human hair and skin. This ink is ejected through a funnel organ as a defense mechanism. When threatened, the octopus releases ink to create a visual screen, confusing predators and allowing for escape. Some species' ink can even temporarily paralyze a predator's senses. This ejection is a coordinated action involving muscles around the sac, demonstrating the octopus's complex nervous system and behaviors. The ink sac is an organ in most cephalopods that secretes this fluid, which can be ejected from a duct opening into the terminal part of the rectum.12
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
octopusDescriptionWhen endangered, they eject an inky substance—a type of melanin-based ink (produced by a gland in the hindgut) mixed with mucus (produced by the octopus’s funnel gland)—through a duct near the anus. The ink is used as a screen that helps to cover the octopus’s escape; the substance produced by…
Read MoreWhen endangered, they eject an inky substance—a type of melanin-based ink (produced by a gland in the hindgut) mixed with mucus (produced by the octopus’s funnel gland)—through a duct near the anus. The ink is used as a screen that helps to cover the octopus’s escape; the substance produced by…
Read More
cephalopodReproduction and life cyclesCuttlefishes squirt their eggs with ink when they are laid to camouflage the otherwise white eggs.
Read MoreCuttlefishes squirt their eggs with ink when they are laid to camouflage the otherwise white eggs.
Read More
cephalopodBehaviourThe ink of cephalopods is used for both defense and escape. In Octopus under attack by a moray eel, the cloud of ink seems to paralyze for some time the eel’s senses of sight and smell. In squids the ink is ejected as a spindle-shaped mass…
Read MoreThe ink of cephalopods is used for both defense and escape. In Octopus under attack by a moray eel, the cloud of ink seems to paralyze for some time the eel’s senses of sight and smell. In squids the ink is ejected as a spindle-shaped mass…
Read More
