Unlike their relatives living in more hospitable depths, deep-sea cephalopods cannot afford to spend energy in protracted flight. Given their low metabolic rate and the low density of prey at such depths, Vampire Squid must use innovative predator avoidance tactics in order to save energy. Their aforementioned bioluminescent "fireworks" are combined with the writhing of glowing arms, erratic movements and escape trajectories. These features make it difficult for a predator to home in.