I started leaving Walker my 16 (almost 17) year sulcata out all year last winter, I've noticed he drinks a lot more water during winter than in the summer. He has been drinking about a half gallon at a time every 3 days with no drinking in between,--meaning he doesn't drink every day-- It has been much colder this year than last year, our temps for the last week have ranged for 19 to 45 Fahrenheit. Early in the fall he wasn't drinking as much and he seemed to have the bubbly eyes syndrome more often, but since his water intake has increased his eyes seem more clear. I can't soak him or make him drink, but at some point it's as if he knows when he needs more water. Anyone else that keeps their tortoises out all year noticed an increase in water intake when it gets cold and they spend less time outside? No matter what the temperature is, Walker will spend about 4 hours out before going back into his house for the night. a pic from today with his no-spill water bowl that holds 6 quarts.