“Don’t judge a book by its cover” begs the Vampire squid. With both a name and appearance that invoke horror stories, it’s tempting to assume this underwater creature is a monster. While its Latin scientific name Vampyroteuthis infernalis literally translates to the “vampire squid from hell,” it’s truly a misnomer. In reality, however, this tiny, dopey creature floats slowly through the water, munching on bits of decomposing leaves. So let’s take a pause on our fantasies of sea monsters, and learn a bit about the vampire squid’s ecology. Maybe it’s really not as scary as it sounds!
With a wild appearance and a mysterious background, you may be wondering what a vampire squid even is. As a matter of fact, it’s not a squid! This marvelous creature is one of a kind. Here, we provide a detailed description of what a vampire squid looks like in addition to some of the history of its classification.
In appearance, the vampire squid looks quite intimidating, but in the case of this sweet, deep-water detritivore, looks can be deceiving. The vampire squid’s gelatinous body has two main parts: the mantle and the cloak, each with its own impressive traits.
The mantle, a part of all cephalopods, is generally seen as the head, though nearly all important systems are stored in the dome-shaped organ. The color of the cloak and mantle varies depending on the light, sometimes looking jet black and sometimes looking more rusty red. Its home lies in an ocean zone where little significant light can be detected, so its color doesn’t have much importance to the squid. Unlike its cephalopod cousins, the vampire squid can’t change its color or texture.
Notably, the vampire squid has the largest eyes in proportion to its body size. When seen underwater, they reflect a bluish glow, adding to its ominous vibe. However, these squids have giant, highly-developed eyes to help them see in the dim light.
In addition to the eyes, two fins perch on either side of the mantle, looking a bit like ears. However, the fins are the squid’s primary source of movement. By flapping the pair of fins, the squid moves through the water.
Vampire squids have eight arms like an octopus. However, this special creature has a webbing that connects the arms together like a frog’s foot. This “cloak” looks similar to a vampire’s cape, contributing to the squid’s name. This marine invertebrate does have suckers on the arms, though the cirri get more of the attention. Cirri are fleshy spines that line the inner side of the arms. Though completely harmless sensory organs, the cirri look like rows of terrifying fangs.
In addition to the eight arms, the vampire squid has another set of appendages. Unfurling from two pockets inside the cloak are two long filaments. Similar to a true squid’s tentacles, the filaments help V. infernalis sense the world around them. Also on the end of each arm are photophores. We’ll dive more into the purpose of these later, but each of these dots is essentially a glowing organ that the squid can turn on and off at will.
Description Overview: Vampire squids have gelatinous, reddish-black bodies, eight arms, two tentacle-like filaments.
|Body Length||30 cm (1 foot)|
|Color||Jet Black to Pale Red, depending on the light|
|Number of Arms||Eight, with suckers on the ends|
|Tentacles?||Two long filaments, similar to a squid’s tentacles used for touch|
|Superpower||Bioluminescent photophores at tips of arms and glowing mucus|
Scientists use taxonomy as an evolutionary family tree. For the vampire squid, classification proved difficult. When first discovered during the deep sea Valdivia Expedition by Carl Chun from 1898-1899, the funky squid was celebrated as proof that marine life exists below 550 meters. However, as with most science, the answer to one question opens up endless new inquiries. The mystery around the vampire squid began.
Without a doubt, the creature is a member of the taxonomic class Cephalopoda, but it wasn’t quite like the others in the group. Was this funky creature a squid or was it an octopus? At first glance, scientists grouped it with the octopuses because it seemingly lacked the two long tentacles that reach beyond the eight arms of true squids. However, because of its two sensory filaments, it’s not a true octopus either. Additionally, the color-changing chromatophores didn’t fully develop in the vampire squid. Whether this proves the vampire squid is prehistoric or is merely a consequence of living in the dark, this mollusk will forever be a reddish black.
The best hypothesis today is that the vampire squid is an ancient relative of its contemporary cousins. While the filaments developed into complete tentacles for squid, the modern octopi lost them at some point in their evolution. In the end, the vampire squid got its very own taxonomic order called Vampyromorphida and family called Vampyroteuthidae. While it’s the only living species in the order, it’s likely that there were other vampyropods that are now extinct. Researchers have found fossils of other vampyropods from the Jurassic Period in Banff national park. Discoveries like this add to evidence that the vampire squid represents an ancient line of cephalopods.
Classification Overview: Vampire squids are neither squid nor octopuses. They are the sole members of the order Vampyromorphida.
Though it will occasionally hunt a live animal, the vampire squid is primarily a detritivore. In the deep ocean, there aren’t too many options. In order to fulfill its energy needs, the slimy invertebrate grazes on any biotic material that sinks down from the waters above. The nutrient-rich “marine snow,” is composed of decomposing plants and animals. Marine snow is the food that supports most of the vampire squid’s activities. Much of the “marine snow” that floats down are infused with bioluminescent organisms. A theory stands that the vampire squid repurposes this bioluminescence for its own glowing mucus!
In addition to the detritus, vampire squids are opportunistic hunters. If they have a chance at some tasty fish or crustaceans, they won’t be picky!
Diet Overview: The vampire squid is a detritivore and opportunistic carnivore eating a combination of crustaceans
Because of their difficulty to study, the life cycle of the vampire squid isn’t very well known. However, scientists have observed juveniles in the wild. Interestingly, the hatchlings are found even deeper in the ocean than the adults. From this, we can infer that spawning happens in these greater depths.
Similar to other cephalopods, females are fertilized after receiving spermatophores from the male. But unlike their cousins that die after laying eggs, the female vampire squid can lay multiple clutches over the years. After hatching, the baby squids live off of a stored internal yolk until they can fend for themselves. Juveniles propel themselves with jet propulsion, but as they grow up, they rely more on their fins. Scientists estimate that they can live for around eight years, but their life span remains a bit of a mystery.
As we’ve learned, V. infernalis is not the terrifying monster it’s cracked up to be. On the contrary, it is a quiet, peaceful creature. However, that doesn’t mean the small squid is safe from other deep-sea predators. A number of other animals enjoy vampire squid for dinner, and our slimy friends need to watch out for large fish and even whales!
When faced with a predator, the vampire squid has a couple of options. While some animals usually respond with a fight, flight, or freeze reaction, the vampire squid is not physically able to fight a predator and can’t swim very fast. Instead, it turns to its wily nature and confuses its attacker. At an initial threat, the squid will perform a feat of gymnastics. By raising its arms above the mantle, its entire body will be enrobed in its cloak. Not only that but turning the cloak inside out creates quite the spectacle. Between the dark red webbing and the fang-like cirri, the vampire squid looks terrifying. More importantly, however, the squid doesn’t look like anything edible. If it’s lucky, the predator will decide to move on to more aesthetically pleasing dinners.
Luckily, the vampire squid has a superpower (or really a couple) that serves as its defense! It can light up in two different ways! First, a light-producing organ called a photophore is located at the tip of each arm. Additionally, while it doesn’t have ink sacs, the vampire squid can produce a glowing mucus that contains microscopic bioluminescent particles, likely repurposed from the marine snow it eats. When threatened, the squid will release a sparkly cloud around itself while simultaneously lighting up its photophores. Between the chaos and distractions, the vampire squid will escape while its pursuers sit confused by the dazzling spectacle.
To swim, vampire squids primarily use their mantle fins. However, in a moment of threat, they can use their fins and cloak to make a quick getaway. Though they can be speedy, they aren’t able to keep it up for long. The squid will be able to sprint just enough to get out of the range of the immediate threat, but then it will run out of energy.
Behavior Overview: To protect itself from predation, the vampire squid uses trickery. By covering itself with its cloak or confusing the attacker with a light show, the vampire squid gains enough time to swim away.
The scariest thing about the vampire squid might be its habitat. Though found in tropical and temperate parts of both the Atlantic and Pacific Oceans, the vampire squid’s home is a far cry from the paradise of a coral reef. Living in the deep ocean, vampire squids are found between 600-900 m (2,000-3,000 ft) below sea level. Not only is such deep water ominously dark, but also the lack of oxygen in the zone can be suffocating.
Generally referred to as the oxygen minimum zone (OMZ), or the shadow zone, these regions develop due to their depth and geologic formations that prevent the water from mixing with its surroundings. Most ocean water has a concentration of dissolved oxygen between 7-8 milligrams per liter (mg/L). In contrast, the vampire squid’s habitat has incredibly low dissolved oxygen levels. In fact, they are commonly found in waters with a concentration of 0.4 (mg/L).
Habitat Overview: The vampire squid lives in the shadow zone of the ocean at depths between 2,000 and 3,000 feet.
In order to live in such an intimidating place, the vampire squid has evolved some critical adaptations to allow it to thrive in the depths of the ocean. Some of these amazing adaptations include a low metabolic rate, special respiratory protein, and neutral buoyancy.
Most oceanic squids have an incredibly high oxygen demand. Lots of oxygen helps true squids move at high speeds to both catch prey and escape predators. Such a high demand makes sense when a squid can spot its prey at a distance. As you go deeper into the ocean, the visibility decreases, and the animals resort to a sit-and-wait strategy for hunting rather than a chase-as-fast-as-you-can. The vampire squid is at this extreme. Not only does the oxygen minimum layer necessitate that it stays relatively inactive, but it also doesn’t even try.
As a result, the vampire squid is – as researcher Brad Seibel sums up – the “hypoxia tolerance champion” in his review of squid metabolism. In his research, Seibel correlated habitat depth to metabolic functioning. He discovered that the vampire squid has the lowest metabolic rate of any cephalopod, more similar to that of a jellyfish. As the habitat depth increases, both aerobic and anaerobic activity decrease.
Given the dismal amount of oxygen in the OMZ, a low metabolic rate doesn’t totally account for the vampire squid’s life at the bottom of the sea. While other cephalopods have proven their adeptness at withstanding conditions of hypoxia, none can match the duration that the vampire squid spends in the oceanic depths. This puzzle indicated that the slimy creatures must have another trick.
That’s where the protein hemocyanin comes in. Analogous to hemoglobin in mammals, hemocyanin transports oxygen around the bodies of invertebrates. The hemocyanin in vampire squids is basically overpowered. It has a higher affinity for oxygen than the same protein in other cephalopods. Because of this, vampire squids more efficiently use the little oxygen that is available to them.
Let’s go SCUBA diving for a minute. Put on your wetsuit, mask, and flippers, and simply jump into the water. But wait! How do you get down to the coral reef?
Achieving neutral buoyancy is a challenge for divers. Between adding weights and releasing air into their vest, divers hope to reach a happy medium of floatation. If the buoyancy is too high or low, the diver has to work hard kicking and swimming to stay in the target depth. Needless to say, it can be quite tiring. The deeper the dive, neutral buoyancy becomes increasingly harder to achieve. Divers must add more weights to reach the depths.
As it would happen, the vampire squid evolved to be naturally, neutrally buoyant! Therefore, the squid doesn’t have to expend any extra energy to stay in the OMZ. It’s a good thing for the squid – when all you eat is marine snow, a tough workout regime isn’t quite in the cards.
Adaptations Overview: In order to survive in the low oxygen environment of the OMZ, the vampire squid has evolved to have a low metabolic rate, a respiratory protein with a high affinity for oxygen, and neutral buoyancy.
While fascinating, the vampire squid’s habitat and attributes make it a challenging study species. All observations of them in their natural habitats have been from recordings of remote operated vehicles (ROVs). Because of the potential disturbance an ROV would cause, it’s likely that there’s a world of fascinating behaviors we have yet to discover about the vampire squid.
Captive research has also been challenging. In 2014, marine biologists at the Monterey Bay Aquarium put a vampire squid on display for the first time in history. While the public got to see a real-life squid, it didn’t compare to seeing an animal in its natural habitat.
The IUCN Red List has not evaluated V. infernalis, so we don’t have a great idea of how the populations are doing. Taking a note from other sea creatures, however, we can hypothesize that climate change and warming waters likely threaten the vampire squid’s habitat.
As it turns out, we’d like to think the vampire squid is more like the sympathetic monster from Frankenstein than a blood-sucking Dracula. But really, it’s incomparable! The slimy squid is a truly amazing animal with some fascinating adaptations that allow it to live in one of the most extreme environments on planet Earth.
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