The Frighteningly Fast Funnel Weaver Spider
Updated: Jan 8
October is here and that means Halloween decorations abound. I’m not a big fan of gory, ghoulish décor or equally grisly horror films, but I do enjoy the more whimsical decorations and entertainment. Of these my favorite are the adorable, often fluffy spiders. I’m tickled by their friendly, yellow eyes glowing from their perfectly round heads; their cartoonish grins affixed via white paint or stitching; and their long legs, soft and spindly, appearing to dance jubilantly even from a standstill (or, rather, a hang-still).
Unfortunately, real life spiders are not—in my mind—at all adorable. Or fluffy. Or jubilant. The film “Arachnophobia” really ruined me and, though I don’t run screaming from the sight of a land-dwelling arachnid, I do keep a wary eye open for them and their webs as I move through the local wild.
My most recent encounter was with a spider who decided to get cozy in a recess of our home’s stone façade, right next to the front door. From the looks of its web it was a barn weaver spider, a small, brown, deeply introverted yet frighteningly fascinating variety of arachnid.
Barn weaver spiders are a common type of spider of the family Agelenidae. These spiders enjoy quiet places with lots of dark corners like wood piles, basements, and barns to build their signature funnel webs. The openings of the webs are wide and non-adhesive and progressively narrow into a funnel and end at a sticky silk den where the spider spends most of its time. Barn funnel weavers are not poisonous and will only bite if provoked or startled. Bites are generally mild or even painless and rarely require any medical treatment.
Forget its odd web, though. That’s not the truly fascinating thing about these spiders: it’s their incredible speed you should be mesmerized by. Many describe them as “very fast”; I saw one enthusiastic blogger write “startingly fast”. I, however, prefer to categorize funnel weaver spiders with superheroes like The Flash. It’s difficult to visually catch these arachnids moving from their dens to outer webs as they launch onto prey and to say it happens in the blink of an eye feels absurdly inaccurate.
To give an example, a YouTube videographer reduced the playback of a recording of a weaver spider retreating to its den to 5% speed. Even so, the videographer was still barely able to catch the spider FIRST turning around and THEN running away. That said, I consider their quickness more of a teleportation situation and, if these spiders have superpowers like that, I’d rather leave them to their introverted lifestyles at the base of their sticky dens.
Mother Nature does not give anything in the local wild superpowers without reason, and the truth is the weaver spider’s non-adhesive outer web means they need to be quick enough to run out of their dens and catch their prey—generally flies and gnats—before it gets away. One variety of funnel weaver was clocked at 1.73 ft/s. That’s “only” 1.18 mph to us humans but when you consider the size of the runner—that particular specimen was ½-inch long—1.18 mph is incredible! Need some math to convince you? I’m happy to comply!
Let’s say a ½-inch spider has a ½-inch running stride and that this spider runs 1.18 mph. Compare it to the average human’s running stride—66 inches—and we can use basic algebra to calculate X, the human’s comparative speed. The answer? A blazing 155.76 mph.
As a kid in Southern California I’d taunt the west coast’s funnel weaver variety by tossing small pieces of grass onto the outer edge of the web, tricking the poor arachnid introverts into darting out in anticipation of a meal. The spider would appear only to be met by a lousy snip of grass and a human child’s goofy grin. Trick or treat, indeed!
Simply, I’m just glad bigger, more aggressive spiders, including the adorable Halloween decoration varieties, are not weaver spider-fast.