My spirit guide is a small green garter snake. While I cannot find much on that specific snake, I have found plenty on snakes in general.
Snake spirit guides are a sign of a major transition. Makes sense since I went from Christianity to Wicca (NOT Christian Wicca, just Wicca).
The way a snake sheds its skin is a symbol of rebirth and fertility. I have 3 kids. Enough said.
They are also a sign of healing from many different cultures. In the Bible (Numbers 21:8-9) it says "The Lord said to Moses, ?Make a snake and put it up on a pole; anyone who is bitten can look at it and live.? 9 So Moses made a bronze snake and put it up on a pole. Then when anyone was bitten by a snake and looked at the bronze snake, they lived." Snakes entwined the staffs both of Hermes (the caduceus) and of Asclepius, where a single snake entwined the rough staff. From this, we get the symbol seen on most every ambulance in America representing the practice of medicine. While healing magick is not my strongest gift, it is one I find myself practicing more and more.