Vampires in the deep

If you go down to the deep-sea tonight, you’re in for a big surprise. We’ve got Goblin sharks and Anglerfish, Fangtooths and Gulper Eels, and Isopods bigger than your eyes.

But deep down there you will find a Halloween marvel, a deep-sea cephalopod of the night. The Vampire squid, Vampuroteuthis infernalis, which in Latin literally means “Vampire squid from hell”. Though contrary to belief, the vampire squid is not a squid at all, but in fact is the only living member of the order “Vampyromorphida’. A close relative of both the octopus and the squid, and sharing many similar qualities, they are often seen as an archaic species.

Like Octopuses, vampire squid have 8 arms. Uniquely they lack feeding tentacles and instead, have rows of cirri that resemble fleshy spines. Like many other deep-sea cephalopods, the vampire squid lacks ink sacks. When under threat they instead wrap their webbed-arms up around their head effectively turning themselves inside out. Here those fleshy spines work as protection against predators and have a slight resemblance to a vampire holding their cape.

Despite the name however, Vampire squid aren’t the blood sucking predators you’d expect, in fact they’re actually quite the opposite. Vampire squid feed on detritus, like marine snow formed of gelatinous zooplankton, diatoms and crustacean remains. They often catch their prey with their two velar filaments (Thread-like fibres they can use to sense things). These are retractile, enabling them to catch falling marine snow, and bring it to their arms. With the one of the lowest metabolic rate of any cephalopods, they are well adapted for the cold deep seas, and have decreased movement.

Thought to inhabit depths of 600 – 1200 metres, their gills have a large surface area, and blue haemocyanin to bind and transport oxygen more efficiently than most other Cephalopods. This adaptation has occurred due to vampire squid inhabiting the Oxygen Minimum Zone, enabling their survival in such a tricky habitat. An Oxygen Minimum Zone is an area of persistent low oxygen saturation within the water column, making it a difficult area for organisms to uptake oxygen.

If anything, these deep-sea dwellers are more prey than predator, with their beaks having been found in a range of large deep-diving fish and mammals. To get away from predators the vampire squid has a pair of large fins on its dorsal surface which enable it to move through the water using fin propulsion. Originally believed to use jet propulsion scientists found that the squid actually undergoes metamorphosis, growing a second pair of fins when they reach a specific size. The first pair of fins which use jet propulsion are then retracted back into the body.

And there you have it, a short introduction to the not so spooky Vampire Squid. Happy Halloween!