The Short Answer
To you, your children, and your pets: no, on the published evidence. To native orbweaving spiders: possibly, and that is an open scientific question rather than a settled one.
Those two answers get collapsed into one in a lot of coverage, usually in whichever direction makes the better headline. They are separate questions with separate evidence, so this page keeps them separate.
Risk to People
Penn State Extension is direct about it: Joro spiders do not have medically important bites. Three separate things have to go wrong before a bite happens at all, and the research says each of them is unlikely.
- They are reluctant to bite. Penn State Extension uses exactly that phrase. A Joro that is picked up generally tries to crawl off and drop to the ground.
- The fangs are small. Penn State Extension states that the fangs have difficulty piercing human skin. University of Georgia researchers have made the same point: even if you managed to annoy one into trying, its fangs likely would not be large enough to break your skin.
- The venom is weak. Where a bite does land, Penn State Extension describes it as less painful than a bee sting. Clemson Extension states that the venom is not medically relevant.
All spiders have venom, because venom is how spiders subdue prey. The question is never whether a spider is venomous but whether the venom does anything to a human being, and for this species the extension literature is consistent that it does not.
Risk to Pets
Clemson Extension addresses people and pets in the same sentence: the venom is not medically relevant and is not known to harm people or pets.
We looked for documented cases of a Joro spider injuring a dog or a cat in the extension and agency literature and did not find any. That is an absence of reports rather than a formal safety study, and it is worth stating it that way rather than dressing it up. A dog that eats a Joro spider is doing something no one has studied; a dog that walks through a Joro web is doing something completely unremarkable.
Temperament
There is a measurement here, and it is a good one. Andy Davis and Amitesh Anerao at the University of Georgia’s Odum School of Ecology tested how spiders respond to being disturbed, using gentle puffs of air from a turkey baster and timing how long each spider stayed frozen before moving again.
Across more than 450 spiders from 10 species, most resumed activity after roughly 90 seconds. Joro spiders stayed motionless for over an hour. The study was published in 2023. Whatever a four-inch spider looks like, its actual behavioral response to a human being walking up to it is to shut down completely and wait.
Risk to the Ecosystem
This is the part that deserves care, because it is where the honest answer is “we do not know yet.”
Robert W. Pemberton surveyed 25 forest sites around Atlanta over three years and published the results in the journal Insects in April 2025. Joro numbers roughly doubled every year: 444 individuals in 2022, 859 in 2023, 1,713 in 2024. Over the same three years and the same sites, seven native orbweaver species fell from 52 individuals to 32 to 18 — a decline of about 40 percent a year.
The two curves are striking. The author does not claim they are causally linked, and neither will we. His stated conclusion is that the dramatic increase in Joro spiders and the concurrent decline in native orbweavers is not proof that the Joro spider caused the decline of native orbweavers. He suggests competition for flying insect prey and for web sites as plausible mechanisms, which is a hypothesis, not a finding.
There is one narrower and better-established concern. University of Georgia’s Turf and Ornamental Pest Management program identifies two places where Joro webs should not be tolerated: around pollinator and flower gardens, and around bee hives. A large sticky web strung across a foraging route catches bees.
What Is Still Uncertain
Stating this plainly is more useful than pretending otherwise:
- Whether Joros are displacing native orbweavers, or merely arriving as they decline for other reasons. Three years of correlation at 25 sites is a real signal and not a proof.
- What the long-term effect on pollinators is beyond the immediate, obvious problem of webs across bee flight paths.
- How far the range will ultimately extend. A 2022 University of Georgia study by Davis and Frick found Joro metabolism roughly double that of the related golden silk spider, a heart rate 77 percent higher, and the ability to survive brief freezes that kill the golden silk spider. The authors concluded Joros could probably survive throughout most of the Eastern Seaboard. Could is not will, and the observed range is currently much smaller than the survivable one.
None of that changes the answer to the question in the title. It changes the answer to a different question, about the spiders around them rather than about you.
Questions
Are Joro spiders dangerous to humans?
No. Penn State Extension states that Joro spiders do not have medically important bites, that they are reluctant to bite, and that their fangs are small and have difficulty piercing human skin. Their venom is weak, and bites are described as less painful than a bee sting.
Do Joro spiders bite?
They can, but it is difficult to provoke. Penn State Extension describes them as reluctant to bite. University of Georgia researchers note that even if you did manage to annoy a Joro into biting you, its fangs likely would not be large enough to pierce your skin. A spider that is handled typically tries to crawl away and drop to the ground rather than bite.
Are Joro spiders dangerous to dogs and cats?
Clemson Extension states that the venom is not medically relevant and is not known to harm people or pets. No source in the university extension literature we reviewed reports a case of a Joro spider harming a dog or a cat.
Are Joro spiders aggressive?
The opposite. A University of Georgia study led by Andy Davis and Amitesh Anerao at the Odum School of Ecology tested more than 450 spiders across 10 species by giving them a gentle puff of air. Most species resumed moving after about 90 seconds. Joro spiders stayed frozen for over an hour. The researchers described them as shy rather than bold.
Are Joro spiders harming native spiders?
This is the genuinely open question. A 2025 study by Robert W. Pemberton in the journal Insects surveyed 25 forest sites around Atlanta from 2022 to 2024 and found Joro numbers roughly doubling each year while seven native orbweaver species declined by about 40 percent annually. The author is explicit that the two patterns together are not proof of cause: in his words, the dramatic increase in Joro spiders and the concurrent decline in native orbweavers is not proof that the Joro spider caused the decline of native orbweavers.
Should I kill Joro spiders?
University of Georgia researchers have said no. Andy Davis has advised people to try to learn to live with them and to remove them only where they obstruct your space. His co-author Benjamin Frick put it more directly: there is really no reason to go around actively squishing them, given that humans, not the spiders, are responsible for their arrival here.
Sources
Every claim above traces to one of the following. Where a source states a limit on what its own evidence proves, that limit is reproduced here rather than dropped.
- Penn State Extension. JorĹŤ Spiders. September 8, 2025. https://extension.psu.edu/joro-spiders
- Clemson Cooperative Extension, Home & Garden Information Center. The JorĹŤ Spider. November 21, 2024. https://hgic.clemson.edu/factsheet/the-joro-spider/
- University of Georgia (Davis and Anerao, Odum School of Ecology). Joro spiders aren’t scary. They’re shy.. May 16, 2023. https://news.uga.edu/joro-spiders-are-shy/
- University of Georgia (Davis and Frick, Physiological Entomology). Joro spiders likely to spread beyond Georgia. March 3, 2022. https://news.uga.edu/joro-spiders-likely-to-spread-beyond-georgia/
- Robert W. Pemberton, Insects. Explosive Growth of the JorĹŤ Spider and Concurrent Decline of Native Orbweaving Spiders in Atlanta, Georgia Forests. April 23, 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC12112690/
- University of Georgia Cooperative Extension. Joro Spider: Trichonephila clavata (Circular 1273). Revised June 16, 2026. https://fieldreport.caes.uga.edu/publications/C1273/
- University of Georgia Turf and Ornamental Pest Management. Managing Joro Spiders in the Landscape. October 2022. https://site.caes.uga.edu/entomologyresearch/2022/10/managing-joro-spiders-in-the-landscape/