Is this spider dangerous? What to check

By the Little Finders Club team · 18 October 2026

The short answer

Most spiders are harmless to people and help by eating pests. In North America, the two main spiders of medical concern are widow spiders, like the glossy black widow with a red hourglass underneath, and recluse spiders, which live mostly in the south-central US.

Almost certainly not. The vast majority of spiders are harmless to people and quietly help by eating flies, mosquitoes and other pests. In North America, only two groups are usually considered medically significant: widow spiders and recluse spiders.

The two to know in North America

Widow spiders

The best known is the black widow. The adult female is glossy black with a round, shiny abdomen and a red or orange hourglass shape on her underside. You often can't see the hourglass from above. Males and young widows are smaller and may be patterned in brown, tan or red, and they are rarely a concern.

Widows build messy, tangled webs in sheltered spots like woodpiles, sheds, garages, meter boxes and under outdoor furniture. They are shy and usually bite only when pressed against skin, for example when someone reaches into a glove or a pile of wood without looking. Other widow species, such as the brown widow, live in warmer areas too.

Recluse spiders

The brown recluse is a plain brown spider. People often look for a dark violin shape on its back, but that mark is unreliable: many harmless brown spiders have similar markings, and some recluses are hard to read. Better clues are:

Six eyes arranged in three pairs, instead of the eight eyes most spiders have. This takes a magnifying glass or a close photo to see.
Plain legs of one even color, with no bands, stripes or obvious spines.
Where you live. Brown recluses are found mostly in the south-central and lower Midwestern United States. Outside that range they are uncommon, and many "recluses" reported elsewhere turn out to be other spiders.

A violin mark alone is not proof that a spider is a recluse.

Common spiders that are generally harmless

Jumping spiders: small, compact and fuzzy, with two big front eyes. They hop rather than run and often seem curious.
Wolf spiders: large, hairy, brown or gray, and fast. Mothers carry their babies on their backs. A bite can hurt, but it is not dangerous for most people.
Orb weavers: the builders of big, round, wheel-shaped webs, often seen in gardens in late summer and fall.
Cellar spiders: tiny bodies on very long, thin legs, hanging in corners of basements and garages. The popular story that they are deadly is a myth.

What to do when you find one

Don't handle spiders, even ones that seem friendly. Kids should look, not touch, and tell an adult.
Leave it be if it is outdoors or out of the way. It is probably eating pests.
Move it outside if it is somewhere inconvenient. An adult can gently place a cup over it, slide a stiff card underneath, and carry it outdoors.
Shake out gloves, shoes and blankets that have been stored in garages or sheds before using them.

If you aren't sure what a spider is, a clear photo from a safe distance is a great way to check it later. Apps like Buglet can help you put a name to the spider, but they identify bugs, not bites.

Safety: If someone is bitten and starts to feel unwell, or the bite gets worse over time, get medical help. In the US, Poison Control is available at 1-800-222-1222. If someone has trouble breathing or seems seriously ill, call emergency services. Many sores blamed on spiders turn out to be something else, such as a skin infection, so a worrying wound should always be checked by a doctor rather than guessed at.

Outside North America

This guide focuses on North America. Other parts of the world have their own spiders of concern, such as funnel-web spiders in Australia, and the advice can differ. If you live or travel elsewhere, follow local health advice about which spiders to watch for.

Quick answers

How can I tell if a spider is a black widow?

An adult female black widow is glossy black with a round abdomen and a red or orange hourglass on her underside. She usually hangs in a messy, tangled web in a sheltered spot.

Is the violin mark enough to identify a brown recluse?

No. Many harmless spiders have similar marks. Recluses have six eyes in three pairs and plain, evenly colored legs, and they live mostly in the south-central US.

Are wolf spiders dangerous?

Wolf spiders are not considered dangerous to most people. They can bite if handled, and the bite may hurt, so it is best to leave them alone.