How the Vampire Squid uses Bioluminescence

The vampire squid (scientific name Vampyroteuthis infernalis) is a most unusual cephalopod. Found in deep-sea conditions in many tropical and temperate oceans of the world at depths of 300 to 3,000 feet, the vampire squid is the only surviving member of its order. Vampire squid are cephalopod creatures known for their ability to use bioluminescence. The vampire squid’s cloak is black, and its eyes can appear red – making its scientific name, which translates to ‘vampire squid from hell,’ appropriate.

Vampire squid can reach about a foot in length. A webbed skin ‘cloak’ connects eight arms that are lined with fleshy spines known as cirri. Only the lower half of its arms have suckers. Two small fins extend from its mantle, looking like floppy ears. The adult vampire squid uses these for locomotion.

Most of the vampire squid’s gelatinous-like body is covered in photophores, organs that emit light through the process of bioluminescence. The vampire squid can control these photophores, turning its light not only ‘on and off’ like a light switch, but modulating intensity and size to confuse predators or attract prey.

Most squid are able to change colors, but at the depths a vampire squid lives color change would be useless as the ocean is too dark for colors to be seen. It also lacks the ink sacs that many other squid species have, for similar reasons. Instead, bioluminescence provides the method through which a vampire squid escapes from would-be predators.

To escape from a predator, a vampire squid firsts turns its cloak inside out with the spiny cirri facing outward. Inside the cloak, the two largest photophores glow intensely like twin eyes. The squid then slowly narrows them to simulate that he is getting ‘further away’. If this display doesn’t do the trick and the predator is still threatening, the squid then releases a cloud of mucus. The mucus is thick and glowing with bioluminescence that will confuse the predator long enough for the vampire squid to make a safe getaway.

The glowing is also thought to provide a passive defense. Soft blue light emitted from the many photophores break up the squid’s silhouette, helping to cloak it from predators that may be lurking below by allowing the squid to blend in to the ambient twilight-like lighting conditions of the ocean at that depth. This defensive strategy is called counter-illumination.

The vampire squid’s glow is also used to attract prey for the squid to eat. The squid has two long sensory filaments it wiggles enticingly. Photophores on the end of the squid’s arms provide the lighting for this display. They swim around in a circle trying to attract a dinner of prawns, or other tiny crustaceans.

The vampire squid has a very slow metabolism, and is able to efficiently make use of what oxygen is available to it in the environment thanks to its webbed cape.

Little is known about the vampire squid’s mating habits due to the depths it inhabits, but scientists speculate that the bioluminescence may also help it find a mate. They lay small groups of eggs that hatch into tiny squidlets that drift through the water. These squids develop their cloak and ability to glow as they mature into adult squid.

Vampire squids are a fascinating part of nature, well adapted for the environment in which they live. Bioluminescence helps the vampire squid survive and thrive in some of the toughest conditions on the planet – deep-sea depths. Last surviving member of their order though they are, vampire squid are bound to exist for many generations to come.