The function of the squid's ink sac is to keep it protected from predators.The ink sac squirts out bursts of ink that allow the squid ample time to escape the threat.
The ink from the squid creates an underwater cloud that temporarily disorients and blinds a predator. This ink is not toxic. The ink sac on the squid is created from muscle and is located on the hind gut of the animal. The ink in the squid is made from melanin.
The squid uses the ink sparingly, as it reproduces at a slow metabolic rate. Therefore, it is used only when the squid is feeling provoked or threatened.