6y0ballpython

I just have a question about the temperature of my ball python's skin.....I have two balls....one small male (595g) and one big female (2400g). Their cages are prospecitively 35G and 40G and the temps are pretty much the same in each (83 deg on cool end, 91 deg on warm end). When I take the smaller male out from under his hide, he feels nice and warm to touch, almost too warm sometimes I wonder. When I take the larger female out from under her hide in the bigger tank, she is cold to touch. She is still nice and active, eating well, behaving normally. The only difference between the two snakes in behavior is that the smaller male likes to stay only under his hide on the warm end (ALL THE TIME....) and the female prefers it under her hide on the cooler side (MOST OF THE TIME.,..) My biggest question is this.....

"Is it ok that my larger female's skin feels quite cool to touch? Does this mean that she isn't warm enough?" Should she feel 85 deg on the outside? She doesn't.....also, her urine is quite cool as well (she peed on me the other day up in my bedroom while I was playing with her and it was cool, not even luke warm). I fear that she is too cold and will develop pneumonia. When I purchased her from Petland here in my home city, the cage that she was in was about 100G (quite large), and her skin was nice and warm to touch. She seems quite happy like she is now and sticks to the cool side of the tank. Sometimes she'll bask a bit, but not for long. I've tried switching her hides to see if it's a preference of hides, but she still stuck to the cool side. The funny thing, is that she feels warmer to touch once we've handled her out of the cage for a half hour or so than when we took her out. The air in the tank feels nice and warm and moist when you put your hand in. I think she's just too big and fat to keep her outer skin warm, but also, her urine is cool as well, so she's the same temp on the inside and on the out. Like I said, she's usually warmer to touch when we're done playing with her than when we started. Kind of a puzzler. She likes to be cool maybe??? Is there any way I can measure her temperature? Any thermometers that I have for humans don't go as low as the 80's. Only the low 90's and then they shut off. Any suggestions as to how I can warm her up? Or should I just leave her? I was always told to just let a dead dog lay......this may be one of those times...???.....? I am just worried about how cold she feels to the touch.