Squid (and also octopus) belong to a group of animals called "Cephalopods" and these animals all shoot out the black ink. They store the ink in ink sacs between their gills. They jet it out with some water in the siphon, a part of their bodies that helps them breathe, move, and feed themselves. Octopus ink is usually black, but squid ink is mostly a blue-black color. They use the ink to help them escape from predators. If they feel under attack, they will shoot out the ink so the predator will not be able to see clearly and then the squids will swim away and escape the predator. Cool right?

Squid have an organ that contains ink inside of their bodies. They have another organ that squirt water (this is one of the ways that squid can move: they use jet propulsion). A squid can squirt ink from its ink-containing organ instead of water.

Great question! Squids and other cephalopods, such as octopi and cuttlefish, use dark ink to confuse their predators and thereby escape from them. The ink itself is contained in an ink sac, which is a muscular pouch that lies beneath the gut. When the squid wants to release ink, it contracts the muscles of the sac, which pushes a small amount of ink out of the opening out the "back side" of the squid.

The ink is mixed with a jet of water from the squid's funnel as well as mucus. The water helps to distribute the ink, and increasing the amount of mucus helps the dark cloud that is released retain a shape that looks similar to the squid. These pseudomorphs, or "false bodies" confuse the predator and allow the squids to escape!