Snakes in the West Valley

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by Pat Jaquith

Snakes usually take us by surprise when we are walking along a path or across the lawn. They may register at first as a stick in the path, but our brain suddenly alters the message and I jump as the “stick” slithers away. Here are some different snakes I have encountered in the West Valley.

Taking a second look, the snake that startled me is a Common Gartersnake. There are two variants; this one has three yellow stripes running lengthwise with black or brown between.

Snake eye. 7.11.23

This Common Gartersnake (Thamnophis sirtalis) often warmed itself on the rocks near the house steps; although I have become accustomed to seeing it near there, my pulse quickens every time! These cold-blooded animals (ectotherms) bask in the sun to warm up and are often found on trails or roadways. In winter they group together in an abandoned animal den, cavities in rocks, or other underground locations below the frost line. They sometimes travel up to 15 miles between their hibernaculum and their summer range.

Common Gartersnake using its forked tongue to help identify me on 4.19.24

This Common Gartersnake is the second variant: the red around the head and along the black stripe sets it apart.

Terrestrial Gartersnakes (Thamnophis elegans) may vary in color, but their narrow pale yellow longitudinal stripes are common. As snakes grow, they shed their skin to allow for the increase in size. The “blue” eye is the result of the preparation for shedding. Sometimes it is called the “blue phase”. Terrestrial Gartersnakes have a mildly venomous saliva. If it bites a human, the result is reported to be irritating, causing redness and minor swelling. When handled, they give off a musky odor as a defense mechanism. Although they are reported to live primarily around wet habitats, this one was on our lawn which is on a rocky hillside.

All the Gartersnakes are viviparous, giving birth to several little snakes. Sometimes we have snakes of several sizes eating insects and small rodents we consider pests.

The other species of snake I have seen in the West Valley is a Rubber Boa – but I didn’t get a picture to prove it! It was near one of the ponds in the DNRC land off Farm to Market Road.

Note about other snake species in Montana: The Montana Natural Heritage Program is a wonderful resource for learning about other species, seeing alternate photos, and seeing where species have been observed. I submitted my photo of the Terrestrial Gartersnake to iNaturalist which a service of the Natural Heritage Program for help with identification. Now, my observation will be added to their information!

When I want to get additional information about a natural subject in Montana, I do a search using ‘MT field guide’ and add the topic: snake, plant, flower, tree, reptile, butterfly… and go from there. It has led me on many informative searches!

For us in the West Valley, Lone Pine State Park has a good selection of information about local topics at the visitor center. They have a live Gophersnake (aka Bullsnake) named Cammo! You can observe how through evolution over thousands of years, he resembles a Prairie Rattlesnake!

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6 months ago

A friend ran across this western gopher snake over in the Many Lakes area this past summer and described it as somewhat aggressive. I had never heard of this species before. His image is attached, without his permission at this point. I’ll check with him for permission.

western gopher snake.jpeg
Lynne Brett
Lynne Brett
4 months ago

Great article! We have many garter snakes in our yard, field and garden. It’s nice to know they are helping to keep down the vole population!