Invertebrates
Vampire Squid
Vampyroteuthis infernalis · also called vampire squid, vampire squid from hell
The vampire squid has a fearsome name and a fearsome look — dark red, cloaked in webbing, with pale glowing eyes — and a life that is the opposite of fearsome. It drifts through the darkest, most oxygen-starved layer of the ocean at minimum effort, eating the debris that falls from the world above.
Overview
The vampire squid lives in the midwater of oceans worldwide, between roughly 600 and 1,200 metres, in the oxygen minimum zone — a band of water so low in oxygen that almost no other cephalopod can survive there. It is small (about the size of a football with its arms spread), gelatinous, and nearly weightless in water, and it moves by gently flapping a pair of ear-like fins or by drifting.
Neither squid nor octopus
Vampyroteuthis is the only living species of its order, a lineage that branched off before octopuses and squid split from each other and that has fossil relatives 165 million years old. It has an octopus-like web between eight arms, but also two unique long retractile filaments and an internal shell remnant. It is a true evolutionary relic.
Feeding on marine snow
Once assumed to be a hunter, the vampire squid was shown by deep-sea cameras to be mostly a detritivore. It trails a sticky filament to gather “marine snow” — the endless drizzle of dead plankton, faecal pellets, and cast-off mucus structures sinking from the sunlit zone — then wipes the filament through mucus on its arms, balls the debris up, and eats it. This is a low-energy diet for a low-energy life.
Defence without ink
The vampire squid cannot make ink — useless in the pitch dark anyway. Instead, when threatened, it squirts a cloud of glowing bioluminescent mucus from its arm tips and slips away in the confusion, or it throws its webbed arms back over its body into a spiny-looking “pineapple posture,” hiding its head and switching off its lights.
Status
The vampire squid has not been assessed by the IUCN. It appears widespread and common in deep water and faces no known specific threat, though the expansion of ocean oxygen minimum zones under climate change is, ironically, likely to give it more habitat while squeezing its competitors.
Vampire Squid: common questions
Is the vampire squid actually a squid?
No, and it is not an octopus either. It is the only living member of its own order, Vampyromorphida, a branch that split off before modern octopuses and squid diverged. It has eight webbed arms like an octopus, plus two thin retractile filaments (modified from a second arm pair) that no octopus has, and an internal remnant of a shell like some squid. Molecular and fossil evidence place it closer to octopuses, but it is genuinely its own thing — a survivor from around 165 million years ago.
Does it drink blood?
Not at all — the name is entirely about appearance. The dark reddish-black colour, the cloak-like webbing between the arms, and the pale eyes (which look red or blue depending on the light) reminded its describer of a vampire's cape, hence "Vampyroteuthis infernalis," roughly "vampire squid from hell." In reality it is a slow, gentle animal that eats detritus. It has no beak-borne bloodsucking habit and does not hunt live prey in any dramatic way.
What does the vampire squid eat, and how?
For a long time it was assumed to be a predator, but observations from deep-sea vehicles showed it is mainly a detritivore. It drifts in the water column trailing one of its two long, sticky filaments, which collects "marine snow" — the constant fall of dead plankton, animal droppings, moulted crustacean shells, and cast-off mucus houses of larvaceans. The squid then wipes the filament through the mucus-secreting suckers on its arms, rolls the debris into a food ball, and eats it. This low-energy diet suits its low-oxygen, food-poor habitat.
How does it survive with almost no oxygen?
The vampire squid lives in the oxygen minimum zone, a mid-depth layer where oxygen levels are a tiny fraction of those at the surface and where most active animals cannot function. It copes with a suite of adaptations — one of the lowest metabolic rates of any cephalopod, a blood pigment (haemocyanin) that binds oxygen very tightly, large gills, a gelatinous, nearly neutrally buoyant body that costs little energy to hold in place, and a lifestyle of drifting rather than swimming. It essentially idles through life in a zone that is a refuge from predators precisely because so little else can live there.