A limiting factor for snakes seems to be low air and ground temperatures. They need external heat to digest their food and some sort of thermal protection for successful hibernation. There have never been many snakes up here at 8000 ft./2400 meters, and no rattlers. While areas farther north but lower in elevation have quite a few rattlers along the streams, e.g. Sybille Canyon. There's a cluster of mountains in central Wyoming, SW of Casper, called the Rattlesnake Range.
Our home pair of garter snakes had kiddies. I saw a teeny snake curving through the grass, likely hunting bugs.
One noticeable effect is that our mouse population has dropped: they usually infest the garage, chew things up, and get into the greenhouse.
Go Snakes!
