Vampire squid a human's inner ear) and ammonium-rich gelatinous tissues closely matching the density of the surrounding seawater. Like many deep-sea cephalopods, the vampire squid lacks ink sacs. If disturbed, it will curl its arms up outwards and wrap them around its body, turning itself inside-out in a way, exposing spiny projections. If highly agitated, it may eject a sticky cloud of bioluminescent mucus containing innumerable orbs of blue light from the arm tips. This luminous barrage, which may last nearly 10 minutes, would presumably serve to daze would-be predators and allow the vampire squid to disappear into the blackness without the
Squid and cross-linked proteins, which is used to kill and tear prey into manageable pieces. The beak is very robust, but does not contain minerals, unlike the teeth and jaws of many other organisms, including marine species. The stomachs of captured whales often have indigestible squid beaks inside. The mouth contains the radula, the rough tongue common to all molluscs except bivalvia, which is equipped with multiple rows of teeth. In some species, toxic saliva helps to control large prey; when subdued, the food can be torn in pieces by the beak, moved to the oesophagus by the radula, and swallowed.