Behavior
What behavioural data known have been gleaned from ephemeral encounters with ROVs; animals are often damaged during capture, and survive for no more than about two months in aquaria. An artificial environment makes reliable observation of nondefensive behaviour difficult.
With their long velar filaments deployed, vampire squid have been observed drifting along in the deep, black ocean currents. If the filaments contact an entity, or if vibrations impinge upon them, the animals investigate with rapid acrobatic movements. They are capable of swimming at speeds equivalent to two body lengths per second, with an acceleration time of five seconds. However, their weak muscles limit stamina considerably.
Unlike their relatives living in more hospitable climes, deep-sea cephalopods cannot afford to expend 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 to conserve energy. Their aforementioned bioluminescent "fireworks" are combined with the writhing of glowing arms, erratic movements and escape trajectories, making it difficult for a predator to home in.
In a threat response called "pumpkin" or "pineapple" posture, the vampire squid inverts its caped arms back over the body, presenting an ostensibly larger form covered in fearsome-looking though harmless spines (called cirri). The underside of the cape is heavily pigmented, masking most of the body's photophores. The glowing arm tips are clustered together far above the animal's head, diverting attack away from critical areas. If a predator were to bite off an arm tip, the vampire squid can regenerate it.
Copepods, prawns and cnidarians have all been reported as prey of vampire squid. Recent research has shown they are the only cephalopod not to hunt living prey. They lack feeding tentacles, but in addition to their eight arms, they have two retractile filaments (hypothesized to be homologous to cephalopod arms), which they use for the capture of food. They combine the waste with mucus secreted from suckers to form balls of food. They feed on detritus, including remains of gelatinous zooplankton such as salps, larvaceans and medusae, moults of crustaceans, and complete copepods, ostracods, amphipods and isopods.
Vampire squid have been found among the stomach contents of large, deepwater fish, such as giant grenadiers, and deep-diving mammals, such as whales and sea lions.
Read more about this topic: Vampire Squid
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