When I am transporting snakes in cold weather I line a small box/tubberwear container with either old towels (clean old towels, nothing that was used as rags etc), and wrap a hot/cold pack (kind of a ice pack to keep things cool, but its a gel and it can hold heat or cold (either freeze it or heat it up in hot water or boiling water) I just use hot water from the tap, wrap it in a towel and put in with the snake...(usually snake is in a snake bag as well).
For short trips this setup works fine...depending on how cold it is where you are. I live in Canada, and sometimes it can be below freezing or close to it...(though I avoid moving reptiles at all once it is below freezing).
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PHLdyPayne