Scorpions
There are around 90 scorpion species in the United States and exactly one whose sting is considered medically significant. Knowing which is the whole question.
3 species, each checked against a reference source. Dangerous ones first — that is the question people arrive with.
Medically significant
Everything else
Start with a photograph
Identify this bug from a photo. The result includes confidence, common lookalikes and a plain safety assessment; read its accuracy and limits before treating a low-evidence photo as definitive.
Found a mark but not the animal? See why a bite cannot identify the bug.
The counter-intuitive rule
Among scorpions, size and pincer shape predict danger better than anything else — and they predict it backwards from what people expect.
- Big body, heavy crab-like pincers — usually mild. It subdues prey by force, so venom does less work.
- Small body, slender tweezer-like pincers — take more seriously. Venom is doing the work instead.
- The Arizona bark scorpion is small, pale and slender-pincered, and it is the one that matters.
- All scorpions glow blue-green under a UV torch, which is by far the best way to find them at night.
It climbs, and that changes where you meet it
The Arizona bark scorpion is the only US scorpion that climbs well. That is why it turns up on walls, in ceilings, in shoes and inside bedding, rather than only under rocks — and it is why the standard advice about shaking out footwear exists. A scorpion found at head height in Arizona deserves more caution than one found under a stone.
Common questions
Which US scorpion is actually dangerous?
The Arizona bark scorpion, Centruroides sculpturatus. It is the only species in the country whose sting is considered medically significant, and effective antivenom exists.
Does a bigger scorpion mean a worse sting?
Generally the opposite. The desert hairy scorpion is the largest in North America and its sting is roughly a bee sting. Heavy pincers mean the animal kills by force rather than venom.
How do I find out if I have scorpions?
A UV torch at night. All scorpions fluoresce blue-green, and a walk around the property after dark will tell you more in ten minutes than anything else.
What should I do if I am stung?
We identify, we don't diagnose. Most stings in healthy adults are extremely painful but not dangerous. Seek medical attention for a sting to a child, or for any symptoms beyond local pain.