the diffenence between a heat rock and a rock that is hot because a light is on it is obvious. the snake will be able to tell the heat is there when it feals it on its back. these snakes do live in holes but have been found durring the day out and about. and in africa the day time temp can get to over 120.
think about how warm 111degs isnt. that is only 12.4 degs warmer than your hands when you hold the snake. not that big of a deal.