Changing Planet

How Do Spiders Fly for Miles? Mystery Solved

As if spiders aren’t unnerving enough, did you know that some of them use an electrostatic charge to leap into the air and fly for miles? They’re probably coming to your house.

Silk flows from a spiny-backed spider. Kunkel Microscopy, Inc./Visuals Unlimited, Inc./Corbis

The flight of the gossamer spider was a curiosity even to Charles Darwin, who noted that his boat, the HMS Beagle, was “inundated by ballooning spiders on a relatively calm, clear day,” according to a new paper by Peter Gorham of the University of Hawaii that’s posted on the arXiv website. (Also see “Darwin the Buddhist? Empathy Writings Reveal Parallels.”)

Darwin watched two species of spider, one smaller, one larger. The first raised its abdomen, released a thread and launched itself horizontally with “unaccountable” speed. A larger species released several threads more than a yard long, which he described as undulating “like films of silk blown by the wind.” The spider then let go of the post it had been perched on, and flew away —an arachnid paraglider in action.

Darwin thought thermal air currents could be the secret of the spiders’ aerial abilities, but that doesn’t explain things like why the threads fanned out and how even fairly heavy spiders launched so quickly when the air was relatively still. Also, as the Physics arXiv blog notes, these spiders have been found at altitudes as high as 2.5 miles (4 kilometers) and are not likely to have gotten there by hot air alone.

Darwin and others also theorized that “electrostatic repulsion” played a role in the fanning of the threads. Lo these many years later, Gorham says that indeed, electrostatic forces could determine the spiders’ flight. (Watch a video of the world’s largest spider.)

Electrifying Research

“There are thus a wide and plausible range of processes by which the strands can acquire initial charge,” Gorham writes. One of these is the charging of the strands by the earth’s atmosphere during spinning in a process called “flow electrification.”

From the arXiv blog:

“There must be a source for this charge, of course. Gorham thinks a likely origin is the Earth itself, which has a negative charge density of about 6 nanoCoulombs per square metre on average. That’s more than enough to give the silk a healthy boost and spiders may well be able to pick out prominences where the charge density is much higher.”

All this explains the spider’s launch power in still air, why large spiders can get such a lift and why the silk strands fan out: “because their negative charges repel.” (Also see “Tarantulas Shoot Silk From Feet, Spider-Man Style.”)

The arXiv blog notes that Gorham’s theory still needs to be tested by some “enterprising biologist.” For that individual and for Gorham, how remarkable it must be to work with ideas blown in on gossamer silk all the way from Darwin.

Follow Liz Langley on Facebook and Twitter.

Liz Langley is the award-winning author of Crazy Little Thing: Why Love and Sex Drive Us Mad and has written for many publications including Salon, Details and the Huffington Post. Follow her on Twitter @LizLangley and at
  • roi’ikka-ta

    this article is hilarious

  • Antoinette Amegbletor

    This is very revealing!! Thanks NaGoe

  • NaTaN

    Ten years ago, college time, I told my classmates how spiders travel from North to South Pole… they found so funny even shot a video of my explanations…

  • biddie

    I have often observed (and wondered about) the strange and seemingly impossible distances and locations between the points that certain spiders locate their major anchor lines for their webs ~~ how did they traverse the distances to get there with their anchor lines?? This idea of utilizing the electrostatic forces is a fascinating idea!!

  • biddie

    Adding to my previous comment, I have often wondered if the spiders have some kind of directional control of where they head as they are building the anchor lines? (( I’m thinking in particular of the golden silk spiders that build their webs where the anchor lines can span 20 or so feet between trees …. ))

  • joão

    this is maybe the main reason and the high oscilation , to the possibility of disc spacecrafts flying

  • shawn gallagher

    we are really not safe if spiders can fly we need to kill all spiders before they can do more than just fly. PREPARE YOURSELF FOR THE FLYING SPIDERS!!!!!!!!!!!!!!!!!!!!!!!

  • Twitchy

    I have it on good word that it is precisely this method that US Space Command uses to propel its spacecraft into near Earth orbit.

    Capsules are encased in a saucer shaped reinforced maylar shroud, inflated and electrostatically charged to skip through the atmosphere.

  • Jason

    I was just asking myself last night how our small orb crab spiders make their webs without being able to fly from one tree to the other. It is impossible without flight. And here we go! Thank you universe!

  • Defiant

    This doesn’t make me like spiders any better…

  • Nick D Waters

    Mystery solved? It’s a plausible working hypothesis.

  • Pestaña

    They can fly now!?!? Flamethrowers. Flamethrowers for everyone.

  • Kimberly Williams

    Ok, I knew baby spiders left the nest on strings of silk thread, but the thought was that they were spo light, they just floated on air much like dust particles. Now we are finding out that their are high techie spiders, hope they do not have the brain power to devise a plan to use their super powers to anhilate the human race for our destruction of their environment! ha! See! Things can come back to bite ya in the hiney! Remember, if you are not part of the solution, then you are part of the problem!

  • corey

    they have been found at an altitude 2.5 miles…… lol, imagine going skydiving and then having one of them land on the rip cord of your parachute….I would be dead…I sure as hell would not try to pull the rip cord if there is a spider on it…and there is a good chance I would probably just take off the parachute to get away from the spider…

  • Liz Langley

    @corey LOL! I think I’d be more afraid of the jumping-out-of-a-plane part than a spider (though it might depend on the size of the spider…) 😉

  • Nir

    As a child i would often play with small spiders…what really surprised me is that spiders have a kind of “spidey sense” like spiderman..they had insanely fast reflexes and would often predict my next move..jumping out of the way of my fingers with superinsectile speed. So this doesnt surprise me at all.

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