I was just handling my little guy and he seemed to be fine just chillin with me, and he opened his mouth as if he was yawning and then closed it after a second. He wasnt facing me but it kind of creeped me out, was he yawning or was he looking for some grub? what are your thoughts?

Also another question. I have a UTH installed on the side of the viv where his hide is. I have yet to see him burrow at all in the past few days since I acquired him but do i absolutely need a dimmer switch and this temperature probe for it? I have a hygrometer and a stand alone thermometer in the viv so the ambient heat is just fine.