Blue garter snake?

Question
Where I live...and I'll keep that quiet for the moment...I have found what I believe to be a blue garter snake? Unfortunately both that I HAVE found were already dead but I did get images of the second one. I'm a wildlife enthusiast...have tons of books...have been a nature/wildlife director...looked online.....and have YET to figure if this is truly what I have found. I've only gotten one response from a local person who said was a western ribbon snake. It does not fit any images that I've seen online or any books regarding that type though. If you can help? I've pictures also...can send somehow if you'd like. Thank you very much for your help..... Carla W

Answer
Hi Carla, Well, there are a few very striking blue morphs of some garter sub-species but they have quite a small native range.  Thamnophis sirtalis pickeringii and T. sirtalis ordinoides are both found only in the northwest.
I suspect there might be a far more mundane explanation behind  the blue garters you found. It was no co-incidence that they were both dead. There's something you should know about dead snakes :)......they turn blue after death! It happens to green coloured snakes particularly. The green colour  is a product of both the blue and yellow pigments. The yellow pigments are unstable and break down quite soon after death leaving the blue pigment visible. Both rough and smooth green snakes (Opheodrys species) and garters will appear  blue after death. Probably the same with ribbon snakes.