Enormous Spiders the Size of Your Palm Are About to Invade the East Coast

A Japanese Joro spider
A Japanese Joro spider feeds on a small grasshopper. (Getty Images)

Here’s what you need to know about these eight-legged travelers.

A batch of unsettlingly large eight-legged visitors are making their way through the country.

Joro spiders are native to Japan, but first popped up in the U.S. around 2013 — now scientists say they’re likely to spread through the east coast as early as this spring. Here’s what you need to know about these large, wayfaring arachnids.

What is a Joro spider?

The species comes in yellow, blue, and red colors, and can grow to be the size of the palm of a human hand. The spider is venomous, and it gets its name from Jorōgumo, a ghostly creature from Japanese folklore that shape-shifts into a beautiful woman before killing its prey. (Unsettling, we know.)

The spiders travel from place to place using a method called “ballooning,” in which the thin silk thread of their webs acts as a parachute, sending fresh hatchlings to a new location. It’s a relatively quick way of getting around, which is why the creatures are expected to make their way to various parts of the U.S.

Where do the Joro spiders live, and where are they headed?

In the United States, they’re largely concentrated in the southeast. Researchers believe they most likely arrived stateside by traveling in shipping containers, and now that they’re here, it’s probable that they’ll continue to spread not just through ballooning, but also by riding along in cars or luggage.

They could spread quite far: Scientists from the University of Georgia have found that they’ll likely make their way up the East Coast as early as May. In Japan, which has a similar climate and roughly the same latitude as America, the critters live throughout the entire country.

“It looks like the Joros could probably survive throughout most of the Eastern Seaboard here, which is pretty sobering,” said Andy Davis, author of a study at the university’s Odum School of Ecology.

The Joro is related to the golden silk spider, which has remained contained to the southeast because of its inability to withstand cold weather. But the University of Georgia’s team found the Joro “has about double the metabolism of its relative, has a 77 percent higher heart rate, and can survive a brief freeze that kills off many of its cousins” — which means it can live in much more diverse conditions.

Should we be worried?

Thankfully, no — unless you have severe arachnophobia.

Even though the Joro is venomous, it’s mostly harmless to humans (and their pets). It only bites when it’s been cornered, and even when it does, its fangs are generally too small to break through our skin.

“The biggest danger to humans is that you might get a face-full of lovely golden silk if you walk through the web,” a specialist on invertebrate zoology told CNN.

The researchers in Georgia say the spiders are more of a nuisance than a danger, and because of that, they’re hopeful people won’t be tempted to harm the creatures unnecessarily.

“There’s really no reason to go around actively squishing them,” said Benjamin Frick, a co-author of the study on the spiders. “Humans are at the root of their invasion. Don’t blame the Joro spider.”