Our two California Desert Tortoises are quietly sleeping the current cool weather days away in their cozy cave. The entrance is covered in part with concrete block (just as it is all year long) as well as a heavy sheet of canvas. My question concerns whether or not there should be a small area left uncovered for them to know their way out. They use this entry/exit all year long except that it's left uncovered during their active times. I want them to know that they are welcome to come out on warm days for a stretch and a drink. We are located in the somewhat high desert area of Aguanga, CA. Some of our days may approach the low 80's in temperature. Your advice will be valued. Thanks, Orvil Hazelton