[Cazador]

Hey Matt,
I hope I'm not over-answering your question, but here goes... Generally speaking, all wild garters brumate at some point for different periods of time. With that said, the books say that snakes in Texas, Florida, and other warm, Southern states may become less active for short periods and could be active at any time throughout the winter, particularly on warm days. I think people sometimes see a snake moving around at cold temperature, albeit slowly, and think that it's not brumating, but this is a normal part of brumation. Captive garters don't have to brumate, but some seem to demand it by refusing to eat and becoming lethargic as the amount of daylight decreases.

Brumation is regulated by temperature and photoperiod. Since high northern and southern latitudes (closer to the north and south poles) experience greater changes in photoperiod than mid-latitudes (closer to the equator), changes in photoperiod has more of an effect on garters at high latitudes than those at mid-latitudes. Temperature is probably the more significant factor though since all bodily processes of ectotherms slow down at lower temperatures. Both factors contribute, though.

Brumation is simply the term applied to reptillian winter lethargy. It's an incomplete form of hibernation (a term generally applied to small mammals during the winter). Reptiles slow down their bodily processes but remain somewhat active during brumation, but ground squirrels, for example, remain completely dormant during hibernation (with the exception of periodic bouts where they bring their body temperature back up to normal for short periods throughout the winter). Hope I gave you the right level of detail.