Snakes in San Mateo County

• 
  Western Rattlesnake

  Crotalus oreganus

  ▲ Venomous

  Heavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.

• 
  Prairie Rattlesnake

  Crotalus viridis

  ▲ Venomous

  Heavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.

Every snake recorded in San Mateo County

Western Terrestrial Garter Snake

Thamnophis elegans

Harmless

Gopher Snake

Pituophis catenifer

Harmless

Aquatic Garter Snake

Thamnophis atratus

Harmless

Common Garter Snake

Thamnophis sirtalis

Harmless

Western Rattlesnake

Crotalus oreganus

▲ Venomous

Ring-necked Snake

Diadophis punctatus

Harmless

North American Racer

Coluber constrictor

Harmless

Northern Rubber Boa

Charina bottae

Harmless

California King Snake

Lampropeltis californiae

Harmless

Common Sharp-tailed Snake

Contia tenuis

Harmless

Forest Sharp-tailed Snake

Contia longicauda

Harmless

Striped Racer

Masticophis lateralis

Harmless

California Mountain Kingsnake

Lampropeltis zonata

Harmless

Prairie Rattlesnake

Crotalus viridis

▲ Venomous

Sierra Garter Snake

Thamnophis couchii

Harmless

Coast Night Snake

Hypsiglena ochrorhynchus

Harmless

Eastern Kingsnake

Lampropeltis getula

Harmless

Compiled from verified GBIF & iNaturalist observations. Informational only.

Snakes in San Mateo County: FAQ

Are there venomous snakes in San Mateo County, California?

Yes. 2 venomous snake species have verified records in San Mateo County, California, including Western Rattlesnake, Prairie Rattlesnake. Most snakes in San Mateo County, California, however, are harmless.

How many snake species live in San Mateo County, California?

10+ snake species have verified records in San Mateo County, California, of which 2 are venomous.

What is the most commonly seen snake in San Mateo County, California?

The Western Terrestrial Garter Snake is the most frequently reported snake in San Mateo County, California, based on verified wildlife observations.

What should I do if I see a venomous snake in San Mateo County, California?

Keep your distance and do not try to catch or kill it. Most bites happen when people handle or corner a snake. If someone is bitten, contact local emergency services or poison control immediately.

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