Joro Spider
HarmlessTrichonephila clavata · also called jorō spider
The Joro spider is an introduced East Asian orbweaver that has spread through the southeastern United States since about 2014 and is moving north. It generated a wave of alarming headlines about giant flying spiders, which is a poor description of ballooning — a dispersal method used by most young spiders. It is large and conspicuous, and it is harmless.
Quick facts
- Bite risk
- Harmless. Fangs are usually too small to break human skin, and the venom is of no consequence to people. Ecological effects are still being studied, but it is not a danger to humans or pets.
- Size
- Body 17–25 mm. Female's body about an inch, with a legspan that can reach three to four inches.
- Appearance
- Bright yellow and blue-grey banded abdomen with red markings underneath, and long black legs with yellow bands. The silk itself has a distinct golden tint.
- Web
- Very large, slightly three-dimensional golden orb web, often several feet across and strung high between trees, power lines and porch eaves.
- Found in
- garden, woods
- Family
- Araneidae
- Range
- 12 US states
How to identify a joro spider
- Very large golden-tinted orb web, often high up and several feet across.
- Bright yellow and blue-grey banded abdomen with long yellow-banded black legs.
- Red markings on the underside of the abdomen.
- Currently concentrated in Georgia and neighbouring states, spreading outward.
How it behaves
Sits in the web and retreats rather than confronting. It does not fly; spiderlings disperse on strands of silk, which every spider species does.
What the joro spider is confused with
One observation settles each of these.
Golden silk orbweavers have conspicuous dark hair tufts on the legs and a longer, more cylindrical abdomen.
Where it lives
If you think you were bitten
- Most suspected spider bites are not spider bites. Studies of patients presenting with a “spider bite” repeatedly find that the large majority are bacterial skin infections — frequently MRSA — which need antibiotics rather than reassurance. A spreading, painful, pus-filled sore is far more likely to be an infection than a spider.
- Wash it, ice it, and watch it. Clean the area with soap and water, apply a cold pack, and keep an eye on it.
- Get medical care if the wound spreads or darkens, if you develop cramping, sweating, fever or severe abdominal pain, or if you are confident it was a widow or a recluse.
- Bring the spider only if it is already dead and to hand. Do not go looking for it. Doctors treat symptoms, not species.
In the US, the Poison Help line is 1-800-222-1222. This site is a reference, not medical advice.