September 13, 2007, at the 45th parallel, just inside the north entrance of Yellowstone National Park. Karen spotted this wandering garter snake in the Gardiner River while I was taking pictures and called me over. Karen had purchase a couple of small field guides the day before, so was able to identify him even as I was snapping pictures. It was actually a very small snake.
This image is in the following video, which can also be accessed here.