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
Humboldt squid fins. Their tentacles bear 100–200 suckers, each lined with razor-sharp teeth, with which they grasp prey and drag it towards a large, sharp beak. Although Humboldt squid have a reputation of being aggressive towards humans, some disagreement exists on this subject. Research suggests these squid are only aggressive while feeding; at other times, they are quite passive. Their behavior while feeding often extends to cannibalism and they have been seen to readily attack injured or vulnerable squid of their own shoal. A quarter of squid stomachs analyzed contained remains of other squid. This behavior may account for a large proportion