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Aquatic Gartersnake (Intergrade)

Thamnophis atratus atratus X zaxanthus X hydrophilus

Photo by Jellis
Published on Project Noah
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38.121, -122.192

Field Notes

Description:

This subspecies has been determined to be an intergradation of these subspecies of aquatic Gartersnakes in a range of the north bay area:<br>
Thamnophis atratus atratus - Santa Cruz Gartersnake <br>
Thamnophis atratus hydrophilus - Oregon Gartersnake <br>
Thamnophis atratus zaxanthus - Diablo Range Gartersnake <br>
This resembles mostly the Diablo Range subspecies with the center being more light colored instead of orange. And it has the wide light color underneath that comes up the sides more then the others. This snake has no visible red.
This was a medium to large Garter.<br>
It was first believed that Gartersnakes were nonvenomous. Turns out they found that they do have venom but in low levels that is only toxic to it's prey and not to humans or large animals.

Habitat:

Spotted at a golf course. It had come out of the landscaping.

Notes:

I spotted this snake just after it captured a Vole. I heard the squeaking as both rolled down hill. The jaws of the snake were still separating and trying to hold onto the vole.
The location lists Intergrade species all being aquatics with a diet mainly on amphibians and fish.
Drought may have changed the diet on these aquatic species.

Reference Links:

Thamnophis atratus intergrades

Species ID Suggestions

Comments (12)
Jellis
Yes Hema. Any oil spill is bad news for birds and more.
HemaShah
what a bad timing for the Galveston oil spill. t is so heartbreaking!!
Jellis
yes but the levels are too low to effect humans. It only effects it's prey.
HemaShah
that is sad indeed. These are venomous?
Jellis
Thank you Hema. And the sad part is it may not have eaten it. These are aquatic Garters. Their diet is frogs, newts and fish. Because of the drought it's diet changes,but their jaws may not be able to open wide enough for something this big. I didn't stick around to see
HemaShah
nice spot! poor cute vole though!
Jellis
Thank you Tiz. I didn't know the location I found it would be the overlap of three species and over time came interbreeding.
Tiz
What an interesting spotting, and great timing! Good to read that it is not toxic to humans, as well as the rest of the information you added :)
Jellis
They figured it could be a intergrade but they still didn't think so because of the vole. Intergrades diet was mostly frogs, newts and fish.
Jeff Dreier
A few years ago during a survey for another species, I found a very similar gartersnake in a drainage pond created by a landslide just east of your sighting (and northeast of the quarry). At the time, I concluded it was an intergrade aquatic gartersnake. I will try to find the photo and post it.

Spotted for Missions

Mission
Reptiles of the World
Mission
Snakes of the World
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Hunters & Animal Food Habits
Mission
Snakes of the United States - Center for Snake Conservation
Photographed
PublishedMarch 18, 2014

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