Identifying Shasta County Garter Snakes

This data is a summary of the data found at the Key to California Gartersnakes web page at CaliforniaHerps.com and information from Stebbins 2003, summarized for data useful to Shasta County Garter Snake identification.

Garter snakes can be difficult to identify if you are not familiar with the typical look of the local species. For example, in some parts of the Oregon Gartersnake range, they look fairly similar in pattern and color to what our Mountain Gartersnakes look like. However, in Shasta County, they do not. There can be a lot of variation in garter snakes within a species, so looking at images of garter snakes may not always allow you to properly identify the specimen.

In Shasta County, the upper labials is probably the easiet way to distinguish the garter snakes. The Oregon Gartersnake and Sierra Gartersnake are the most difficult to distinguish from each other by upper labials.

All images on this page are links to larger versions of the image.

The images currently labeled as Oregon Gartersnake are actually a sister subspecies, the Diablo Garter Snake. The specimen used is from Contra Costa County where it was found hunting California Red-legged Frog tadpoles. While the scale counts and shape are the same as what you would expect from an Oregon Gartersnake, the coloration is different. They will be replaced by Oregon Gartersnake photos once I have some decent photos that demonstrate the proper identification keys.

Use Range Maps

The Mountain Gartersnake and Valley Gartersnake probably can be found throughout Shasta County. The Oregon Gartersnake is found primarily in the western portion of Shasta County. The Sierra Gartersnake is found primarily in the eastern portion of Shasta County.

According to Stebbins 1985 the Oregon Gartersnake and the Sierra Gartersnake both occur in the Pit River drainage, but most populations are either one or the other. According to Stebbins 2003 (pg 381) they can not always be reliably distinguished there, and some apparent hybrids have been found.

Count the Upper Labials

When counting upper labials, the first upper labial is the one closest to nose. The seventh or eighth is the one farthest from the nose.

Chin Shields

Internasals

The internasals are the pair of front pair most scales on the top of the head, directly between the nostrils.

Pit River Aquatics

In the Pit River Drainage, the Sierra Gartersnake and the Oregon Gartersnake both occur and can be difficult to distinguish, and some specimens may be hybrids. The garter snakes shown are from the Pit River drainage.

In Stebbins 1985 these two garters are classified as different subspecies of a single species, with a note that taxonomy may split them into different species. In Stebbins 2003 they are classified as separate species.