Even if you've never been afraid of the dark, you'll definitely find things to fear in the ocean depths where sunlight doesn't penetrate. Vampire sea spiders creep along the bottom more than 3 miles below the surface, on legs sometimes spanning more than 2 feet in length, looking for prey from which they can suck vital fluids through their long, straw-like proboscis. Despite their creepy-crawly appearance and vampiric ways, you'll be in danger only if you're a sponge or sea slug.
What They Are
Reminiscent of something out of Star Wars, with long skinny legs extending from a stick-like body, sea spiders stroll across the ocean floor in search of a meal. Although exact classification of sea spiders has defied science for more than 100 years, the sea spider is a true-blue arthropod known as a pycogonid. Its segmented exoskeleton shows that it is closely related to spiders living on land, although some types of sea spiders have five pairs of legs and not four.
Where to Find Them
If you're aching to encounter a vampire sea spider face-to-face, you'll need to dress warmly. More than 250 species are found in the frigid waters of the Antarctic Sea, more than anywhere else in the world. The cold waters of the antarctic hold more oxygen than warm-water oceans, and the vampire sea spider absorbs it through spores throughout its body, allowing it to grow to the size of a trash can lid.
No Deadbeat Dads
When a female sea spider releases her eggs during mating, the male scoops them up, fertilizes them and cements them together with fluid from his body. Far from being monogamous, the male may collect eggs from a half dozen females. Once they are cemented, the male carries the balls of eggs under his body in structures known as ovigers until the eggs hatch. Some species continue to carry hatched larvae during their early development before depositing them on a colony of soft coral where they'll have sufficient food.
Here's Not Looking at You, Kid
Most arachnids crawling on the land have eight eyes, but you won't find any eyes on the vampire sea spider. Crawling around in complete darkness, the vampire sea spider would not be able to see even if it had eyes. Instead it uses chemoreceptors on its antennae and elsewhere on its body to detect its prey chemically before sucking its vital juices with the mouth at the end of its long proboscis. Two favorites of the vampire sea spider are sea slugs and sponges. It has also been known to eat soft corals such as Alcyonium antarcticum and Clavularia frankliniana.
- ABC Science: Vampire Sea Spiders Suck on Prey
- National Geographic: 5 Weirdest Antarctic Species
- Craig McClain: The Relationship Between Dissolved Oxygen Concentration and Maximum Size in Deep-Sea Turrid Gastropods [PDF]
- Deep Sea News: Giant Antarctic Sea Creatures
- National Geographic: Giant, Unknown Animals Found off Antarctica
- Underwater Field Guide to Ross Island and McMurdo Sound, Antarctica by Peter Brueggeman [PDF]
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