Britannica AI Icon

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

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

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.