Our free ranged male C. senegalensis will hunt out the UVB lights if he needs it. It's kind of funny actually, if I don't put him outside once a week, he starts to get very very restless and will find a way to be exposed to the UVB bulbs across the room. He doesn't care too much for the basking lights, since he has his own, but he really knows where to go to get that UVB.