A terrifying species of spider that once plagued the northeastern US is making a return, and the new infestation is spreading deeper into the country than ever before.
The bright yellow Joro Spider, which originated in Japan, China, Korea, Taiwan, and other parts of Asia, has seen its population spike since they last plagued the US in 2024.
Experts cautioned that these venomous arachnids are poised to spread across the US thanks to a process called ballooning, where they form ‘sail-like trails of silk that lift them off the ground.’
Currently, a new wave of Joros is preparing to hatch this spring, with this brood capable of flying several feet through the air and potentially hitching rides all over the nation.
The spiders have been seen in Georgia, Tennessee, the Carolinas, California, Virginia, Maryland, and Pennsylvania, typically in the fall, when they reach their full size between August and October.
Female Joro spiders have a bright yellow body with blue strips and red markings, making them hard to miss. Males can be spotted by their more brownish color and smaller size.
The females also build large, golden webs to capture their prey, and these are increasingly common as the population swells.
Moreover, the females tend to grow much larger than the males, sometimes growing to be as large as a human hand. They also occasionally eat their male counterparts.
The Jorō spider can grow to be larger than a human hand, although they are typically around four inches with their legs spread out
Jorō spiders are native to China and came to the US in 2014, first appearing in Georgia. They have since spread to South Carolina, North Carolina, Tennessee, West Virginia, Oklahoma, Alabama and Maryland
If you live in or near a city, you might see more Joro spiders, as they are surprisingly tolerant of urban environments, including busy roads, vibrations, noise, and crowded structures, in comparison to many spiders varieties native to the US.
The University of Georgia’s Odum School of Ecology experimented with tuning forks that simulated road vibrations, finding that the spider was relatively unaffected by noise that would affect other arachnids.
Andy Davis from the University of Georgia said in a statement: ‘These Joro webs are everywhere in the fall, including right next to busy roads, and the spiders seem to be able to make a living there. For some reason, these spiders seem urban tolerant.’
Despite its opportunity for flight and venomous nature, researchers stress that there is no danger posed to humans or pets.
José R. Ramírez-Garofalo, an ecologist based on Staten Island, previously told the Daily Mail in 2023: ‘There have been no documented fatalities, nor any notable medically significant bites.’
‘Taken together with their behavior (they are very reluctant to bite) and the evidence from the literature, they really pose no threat to humans or our pets.’
Despite posing no threat to people, the invasiveness of the spider cannot be questioned.
Joro Spiders are believed to have entered the US over a decade ago in shipping containers from East Asia that were headed for Georgia.
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A venomous eight-inch-long spider native to Asia, whose palm-sized females cannibalize their male mates, is flying up America’s East Coast and even spreading out west
Since then, the disturbing-looking species has spread far and wide when new eggs hatch in the spring. The Joro is expected to soon reach Canada.
According to the academic journal Arthropoda, the Joro’s fast population growth is due to its high metabolism, rapid heart rate and tolerance for cold weather.
To test the spider’s tolerance to cold weather, researchers have frozen more than two dozen samples, with more than seventy-five percent remaining unaffected.
The spider’s eggs normally hatch between May and June and take a few months to reach full size and start looking for mates.
While their spread across the US may end up being more of a annoyance than a full blown infestation, David Coyle of Clemson University noted that people who don’t want the spiders around can easily move them with a broom or stick.
However, the assistant professor in the Department of Forestry and Environmental Conservation cautioned that Joro spiders are still considered an invasive breed that requires more attention from the scientific community.
‘These are not just benign spiders coming to catch and kill bad things; these are pushing out native species and catching and killing whatever happens to get in their webs,’ Coyle said.
