Vampyroteuthis lives in the oxygen minimum zone, a mid-water layer where dissolved oxygen falls too low for most active predators. Chasing prey there is metabolically impractical, and the animal has the lowest metabolic rate measured in any cephalopod, along with a large gill surface and blood pigment with a high oxygen affinity.
What it eats was established by Henk-Jan Hoving and Bruce Robison in 2012 using submersible observation and gut content analysis. The squid extends one of two thin retractile filaments, which collects sinking particles. Mucus secreted by the arm tips binds the material into a food ball that suckers and cirri pass to the mouth. Gut contents are dominated by faecal pellets, crustacean moults and gelatinous debris.
The name misleads twice over. The animal is neither a squid nor a blood feeder; it is the sole survivor of its own order, Vampyromorphida. Its defence is also unusual: lacking ink, it inverts its web over itself in a pineapple posture and can eject a cloud of luminous mucus.