Venomous spiders in California

Venomous spiders living in California

4species

Black widow, Desert recluse, Tarantula, Brown widow.

How to recognize them

Black widow Latrodectus mactans, L. variolus, L. hesperus

Shiny black female with a round abdomen
Red hourglass or two red marks under the abdomen
Messy, strong web low to the ground, often in garages, wood piles and water meters

Desert recluse Loxosceles deserta

Pale tan recluse with a faint violin mark
Six eyes in three pairs
Plain legs with no bands

Tarantula Aphonopelma spp.

Large, hairy, brown to black spider
Lives in a burrow with silk around the entrance
Males wander in late summer and fall looking for mates

Brown widow Latrodectus geometricus

Tan to dark brown female with an orange hourglass
Spiky round egg sacs that look like burrs
Webs under patio chairs, mailboxes and eaves

Almost all spiders have venom, but very few can hurt people. We list the ones with medically significant bites plus a few that people often worry about.

Counties with records

None recorded
1 species
2
3 to 4
5 or more

Venomous spiders with open GBIF records, by county: 48 counties so far. Blank does not mean absent.

Active months

Open records of venomous spiders in California by month; most fall in July to November.

Harmless spiders people mistake for them

Black Widow vs False Widow False widow: harmless

Quick answers

Questions

How many venomous spiders are in California?

4 species live in the state: Black widow, Desert recluse, Tarantula and Brown widow.

Which venomous spiders in California are dangerous?

Black widow and Desert recluse: bites or stings need medical care.

When are venomous spiders most active in California?

Most open records fall in July to November.

Which harmless spiders get mistaken for venomous ones in California?

False widow. See the side-by-side comparisons below.