Vampire squid

Lore & Background

The genus name Vampyroteuthis combines Latin vampyrus ('vampire') and Ancient Greek teuthís ('squid'), while the species name infernalis means 'of hell' in Latin; the name was inspired by its dark colour and cloaklike webbing, not its feeding habits, as it feeds on detritus, not blood. The vampire squid can reach a maximum total length of about 30 cm. Its gelatinous body varies from velvety jet-black to pale reddish. A webbing of skin connects its eight arms, each lined with rows of fleshy spines or cirri; only the distal halves of the arms have suckers. Its limpid, globular eyes are proportionately the largest among cephalopods, with a 15 cm squid possessing eyes 2.5 cm in diameter. Mature adults have a pair of small fins projecting from the lateral sides of the mantle, which serve as their primary means of propulsion. The vampire squid is almost entirely covered in light-producing organs called photophores, capable of producing disorienting flashes of light. Two larger white areas on top of the head are now identified as photoreceptors, not photophores.

Reader's Guide

The vampire squid is significant as a phylogenetic relict, being the only surviving member of the order Vampyromorphida, and as the extant sister taxon to all octopuses. Its adaptations to the oxygen minimum zone (OMZ) are remarkable: it is the only cephalopod able to live its entire life cycle at oxygen saturations as low as 3%. Its mass-specific metabolic rate is the lowest among deep-sea cephalopods, and its blue blood's hemocyanin binds oxygen more efficiently than in other cephalopods, aided by gills with an especially large surface area. The vampire squid's ability to thrive in OMZs also keeps it safe from apex predators that require large amounts of oxygen. Its large eyes and optic lobes may be adaptations for greater sensitivity to distant bioluminescence. The vampire squid thus remains a unique and ancient lineage, offering insights into deep-sea evolution and survival in extreme environments.

Did You Know?

• The vampire squid's name was inspired by its dark colour and cloaklike webbing, not its feeding habits—it feeds on detritus, not blood.
• It has the largest eyes relative to body size among cephalopods, with a 15 cm squid having eyes 2.5 cm in diameter.
• The vampire squid is well-adapted to oxygen minimum zones, though it is not the only cephalopod to inhabit such low-oxygen environments, and oxygen saturation levels vary across sources.
• A proposed second species, Vampyroteuthis pseudoinfernalis, was described in 2024, but as of the current widely-known canon (up to 2023), this species has not been established in mainstream scientific literature.

A Class Defined by Extremes

Cephalopods span an almost incomprehensible range of body sizes. At the tiny end, some species reach maturity at barely a centimetre in length and weigh under a gram. At the opposite extreme, the giant squid stretches past ten metres, and the colossal squid can tip the scales at nearly five hundred kilograms, earning its place among the largest invertebrates still alive today. When you factor in the lightest hatchlings alongside the heaviest adults, the class covers more than nine orders of magnitude in mass—a spread exceeding three billion times. Beyond overall body size, certain cephalopods are also noted for individual anatomical features of exceptional proportion, pushing the boundaries of what a single organism can achieve. This extraordinary diversity in scale makes the group one of the most size-variable in the entire animal kingdom, and it underscores why no single measurement can fully capture the physical story of a cephalopod.

Giants of a Deeper Past

Long before modern squids and octopuses dominated the oceans, cephalopods held the title of Earth's largest organisms. The fossil record preserves numerous species rivaling today's biggest squids in bulk, spanning ammonoids, belemnoids, nautiloids, orthoceratoids, teuthids, and vampyromorphids—the last being the order that includes the vampire squid. When it comes to sheer mass, the giant shelled ammonoids and endocerid nautiloids are likely the heaviest cephalopods ever to exist, though even they may have been outmatched by the largest living cephalopods if one considers only soft tissue weight. Over the centuries, scientists have also proposed the existence of cephalopods dwarfing both giant and colossal squids. The most famous such claim was the St. Augustine Monster, a multi-tonne carcass that washed up on Florida's coast in 1896. Tissue reanalyses in 1995 and 2004, however, conclusively identified it—and similar specimens—as nothing more than the collagenous matrix of whale blubber, deflating one of teuthology's most persistent myths.

Tentacles of Legend and Story

Giant cephalopods have captivated the human imagination for millennia. Among the earliest surviving written accounts are those of Aristotle and Pliny the Elder, both of whom described squids of remarkable size. Sailors' tales of enormous squid have circulated since antiquity and are widely believed to have seeded the Nordic legend of the kraken, a creature said to be island-sized and capable of swallowing whole ships. Parallel tentacled monsters appear in the folklore of Japan (Akkorokamui), New Zealand (Te Wheke-a-Muturangi), the Caribbean (the Lusca), and Greek mythology (Scylla), while some eyewitness reports of sea serpents may likewise trace back to giant squid encounters. In modern fiction, the giant squid took centre stage in Jules Verne's 1870 novel Twenty Thousand Leagues Under the Seas and its numerous film adaptations, in the 1955 monster picture It Came from Beneath the Sea, and in Peter Benchley's 1991 novel Beast along with its television adaptation. The species' charismatic megafaunal status has even led to proposals for it to serve as an emblematic animal for marine invertebrate conservation, while life-sized models and preserved specimens remain staples of natural history museums worldwide.

Measuring the Unmeasurable

Pinpointing the true size of a cephalopod is far from straightforward. Mantle length, the standard metric in the scientific literature for coleoid species, is measured as a straight-line distance along the dorsal midline from the anterior edge of the mantle to its posterior end or the apex of the united fins, whichever is longer. In eight-limbed octopods, where head and mantle are so fused that the anterior boundary is ambiguous, the measurement instead begins at the midpoint between the eyes. Total length, by contrast, extends from the rear of the mantle or fins to the tip of the longest limb with all appendages outstretched along the body axis. Because limbs can be stretched well beyond their natural resting length and are frequently damaged in preserved specimens, mantle length is generally regarded as the more dependable indicator of overall size. A third metric, standard length, combines the mantle, head, and arms while excluding the long feeding tentacles—a distinction that proves especially useful for species like the giant squid, where those tentacles can rival or exceed the rest of the body.