The vampire squid – a deep-sea monster or a misunderstood mollusc?

Neither squid nor vampire, Vampyroteuthis infernalis is a mysterious deep-sea member of the Cephalopod class of molluscs. The last of its kind, the vampire squid is the only living member of the order Vampyromorphida. Because of its curious name (which literally means ‘vampire squid from hell’ in Latin) and intimidating appearance, the vampire squid has captured the minds of people worldwide. However, this elusive species remains a mystery to many of us.

A cloak of eight webbed arms, lined with spikes. Dark-red skin. Large, pale blue eyes. An occupant of the ‘twilight zone’, beyond the reach of sunlight, the vampire squid drifts, waiting for its next catch. What is its next catch? Probably not what you’d think! The name ‘vampire squid’ is a bit of a misnomer. The species’ closest living relatives are the eight-armed octopuses, rather than the ten-limbed squid. The vampire squid also doesn’t feed by draining fellow deep-sea dwellers of their blood. Despite its name, it’s actually better adapted for defence than hunting.

The vampire squid uses the cloak for which it was named to deter predators. When threatened, it inverts, raising its arms over its head to obscure its body with its webbing and expose its rows of spikes to ward off attackers. If this isn’t enough, it can also expel a bioluminescent mucus that would startle any predator in the darkness of the deep ocean, allowing it to escape. Even its dark-red skin colour offers it some security. The red wavelengths of the visible light spectrum are the least able to penetrate the ocean, reaching depths of up to fifteen metres. For this reason, any red-pigmented creatures will appear black in the deeper layers. In the twilight zone (200–1,000m depth), where 99% of the visible light has been filtered out, creatures with red pigmentation will appear black and are invisible against the near-lightless backdrop of the deep sea. This means that, at the depths that the vampire squid is known to occupy (beyond 600m), it will be near-invisible to its predators (mainly deep-diving mammals and large deep-sea fish).

If the vampire squid is not a predator, then what does it eat? Food is limited in the vastness of the twilight zone, which covers 60% of the Earth’s surface. As such, many animals in this habitat are opportunistic, tending to feed on whatever might fall from the more productive upper layers of the ocean. The vampire squid is one such animal, mainly eating ‘marine snow’, consisting of small clumps of dead plankton, faecal matter, and mucus that fall from the top of the ocean to the deep. It captures this marine snow using two long feeding filaments, similar to fishing lines that it deploys as it floats in the water column. It then retracts these filaments to scrape off its ‘catch’ with its beak, located between its eight arms.

In addition to its unique appearance, the vampire squid has a certain characteristic that sets it apart from its distant cephalopod relatives. Most octopuses and squid that reside in shallower waters tend to only live for one to three years, and most, if not all, female cephalopods spend all of their reproductive energy producing just one clutch of eggs. However, it has been suggested that female vampire squid undergo over twenty reproductive cycles throughout their lifetime. As such, vampire squid may have much longer (more than triple) lifespans than other cephalopods – potentially up to ten years! Perhaps, then, the ‘vampire’ part of their name isn’t so inaccurate after all.

Rachel Herbert-Goddard is a freelance writer based in the UK.