Camel Spiders: Murderous Speed Demons of the Desert


Camel spiders (Eremobates spp.) have a fierce reputation but, in truth, they aren't spiders at all, but solifugids. Kristie Reddick/The Bug Chicks

Some animals have a reputation that's hard to shake. Take the camel spider — many Americans are familiar with them based on photos that came out of the Iraq War in the early 2000s: a giant desert spider with a leg span somewhere between the size of a pack of cigarettes and a full-grown man's calf (this turned out to be a trick of forced perspective). There were rumors they ran through the desert screaming and jumping on camels, that they would hide in ambush in sleeping bags, ready to inject you with venom.

But U.S. military personnel are not the first to tell stories about the camel spider: In South Africa, they're called haarskeerders, or beard trimmers, because some people believe if you sleep on the ground, camel spiders will come trim your hair in your sleep and use it to line their nests. In North Africa and the Middle East, legend has it they nip at the bellies of camels until their intestines fall out so they can eat them or that they lay eggs in their stomachs.

Solifugids, Not Spiders

None of this is true, of course. For starters, camel spiders are not spiders at all, but solifugids. These arachnids live on every continent except Antarctica and Australia, and all 1,150 species have eight legs and two body sections like spiders, scorpions, pseudoscorpions, ticks and mites, but they're different enough to belong to their own order. Secondly, they're aggressive, but they're also nonvenomous, and the large jaws of most species can't even break through human skin, much less a camel's belly. The largest camel spider has a leg span of around 6 to 8 inches (15 to 20 centimeters), which is big for a spider, but it's not horror movie territory, and they seem take little to no observable interest in human hair.

"The thing about solifugids is you don't really need to make stuff up about them for them to be fascinating," says Kristie Reddick, founder of The Bug Chicks, an educational company that uses arthropods to teach young people about social issues like prejudice, racism, educational potential and personal development. "I was in Kenya when I first saw one, and I went to catch it and it ran up the side of the wall — right up to my eye height. It reared back and rubbed its jaws together to stridulate — some people say they scream, but it's more of a hissing, rasping noise. It had such an attitude — I just fell in love."

It would seem difficult to fall in love with an arachnid with the stage presence of a pro wrestler and the body of an animal whose parts were scavenged from the invertebrate salvage yard, but such is the allure of the camel spider.

"If you do a rapid count of what appear to be legs, they look like they have 10 legs, but their first pair are actually mouthparts called pedipalps," says Reddick. "I kind of think of them as mouth hands. They help facilitate bringing prey into their big jaws. When they run, they use them kind of like antennae or long legs in the front."

Nonvenomous Arachnids

Most solifugids are nocturnal, extremely territorial and top predators in arid ecosystems: They eat other predators in the same size range as them, or a bit larger. They even eat each other. They don't have venom like spiders — it's unnecessary because their jaws are so powerful. They can manipulate their food through their mouths by sawing their prey back and forth through like an old-timey cartoon character eating a cob of corn.

Solifugids are also insanely fast, able to reach speeds of up to 10 mph (16 kph), and seem to be able to run for as long as you care to chase them. But with an indefatigable body comes a metabolism that requires nearly constant fueling. So, they eat a lot, but that doesn't necessarily explain one solifugid behavior: mass ant assassinations, like the one in this video:

For some reason, camel spiders will sometimes go after an ant's nest, just tearing ants in half right and left until they're surrounded by an enormous heap of sawn-in-half ant carcasses. Some scientists think maybe they're killing the ants to save them as a snack for later, but Reddick published a paper in 2014 about the diet of solifugids, and she and her co-author found they don't particularly like eating ants. Another explanation for this behavior could be that they're trying to clear out the ant nest in order to find a nice place to escape the desert sun, but it's really a mystery as to why they do this.

"The camel spider in this video could be dispatching with soldier ants in order to eat the larvae and pupae the ants were guarding — these don't bite and are super soft, squishy little protein and fat bombs," says Reddick. "Toward the end of the video, you can tell that she's eating, as her abdomen is enlarging and you can see the swallowing action, so that might be one possible explanation."

But you can add the mass murder of ants to the long list of things scientists don't understand about solifugids. But remember — even though they act like insane little fast zombies, they can't hurt you:

"Just because something is a predator, or even defensive or aggressive, it doesn't make it a bad or mean animal," says Reddick. "Solifugids have so much great attitude, and they're soft and fuzzy — when you pet one, it's like petting a little mouse. A little demon mouse."