To read the headlines, you would think the entire eastern seaboard is about to become the setting of a horror movie. “Giant” spiders “the size of a child’s hand” are “expected to colonize the entire East Coast.” They’ll use “tiny, terrifying parachutes” to “drop from the sky.” Oh, and they’re venomous.
Go ahead, scream. Vow to never go outside again. Come back when you’re ready, and we’ll talk about what these spiders—they’re called joro spiders, by the way—are actually like. Spoiler: They don’t really fly, they aren’t that big, they haven’t colonized the East Coast despite years of dire warnings, and they’re not going to kill you. Let’s start with that first one.
Are joro spiders venomous?
Technically yes, but they can’t really hurt you.
Here’s the thing: All spiders are venomous. What we call venom is their way of digesting food. Remember, spiders eat bugs and creatures smaller than themselves, and the venom is what they use to liquify and gulp down their prey’s insides. That’s pretty metal, but on a small scale. If you are larger than a housefly, you don’t have much to worry about.
Some spiders do produce enough venom to cause their bites to be painful (or, in rare cases, deadly) to humans. But the joro is not one of them. Its fangs aren’t usually even big enough to get through human skin. You’ll be fine. Or as the entomologists at the University of Georgia put it at JoroWatch: “From our experience collecting hundreds of these spiders, having them in our hair and wandering on our arms, and interacting with thousands of webs, they have not bit.”
Are joro spiders actually as big as your hand?
Reports have compared the spider’s size to a child’s hand, or to an adult’s palm. Like, okay, but barely, and only if you measure their outstretched legs. These spiders are bigger than what you’re probably used to if you live in the northeast, but they’re not tarantula-sized or anything,
The female’s body is about an inch long; the male’s body is less than half an inch. Here’s a photo of a joro spider on a person’s hand (scroll down to the gray-haired lady in the red shirt who is holding it and smiling at it like it’s an adorable baby). You have eaten jelly beans larger than this.
Are joro spiders going to rain from the sky?
This is another exaggeration. The truth is that these guys, like many other spiders, can travel by “ballooning.” This means they release a few strands of silk into the air and let the wind pick them up (this phenomenon was illustrated in the “adorable” ending of Charlotte’s Web). They can float for miles if they catch the right breeze, which led to speculation in 2022 that a few of them might be able to make it as far as D.C. that year.
We don’t actually know how far they’ll be able to travel, though, and there’s no reason to believe they’ll be dropping from the sky all over the east coast. The 2022 fuss was sparked by a study from researchers at the University of Georgia, where they calculated that the joro spider should be able to withstand cold temperatures. A 2023 study calculated that much of the northeastern U.S. has habitats that the joro spider might like to live in, but there has been no mass migration.
Where do joro spiders live?
Joro spiders, originally from Japan, have been living in Georgia since 2013. It’s now 2024, and despite the dire warnings of 2022, these spiders still live in a small area of the south, mainly in parts of Georgia and neighboring states.
You can keep tabs on their expanding (or not) empire by checking this page on iNaturalist, where people can report sightings. There are no joro spiders on the map in New York, Philadelphia, New Jersey, or even Washington, D. C. There are a few sightings in Baltimore from September 2023. It’s certainly possible the spiders live in areas where they haven’t been reported yet, but there’s no reason to expect them to parachute en masse into New York or other cities that are well outside their current range.
Should you kill joro spiders?
No, actually! Some invasive species can be problematic in their new environment. Lanternflies, for example, have “squish on sight” status where I live in Pennsylvania.
But joro spiders aren’t expected to cause any significant damage or disruption. They’re just spiders, and they just want to eat bugs. They might actually be beneficial, since they can eat mosquitoes, stinkbugs, and other insects that are themselves problematic. One of the authors of the 2022 study told the press that “people should try to learn to live with them,” and that there’s no need to kill a spider that’s just trying to live its little spider life. I, for one, welcome our new stinkbug-eating overlords.
