Balls can't generate heat the way other pythons do. I've read that, instead, they leave their eggs to bask outside of their den and return to brood when their bodies have warmed up. The temperature is likely warm and cozy inside an African burrow, as well.. so that's another consideration. In a captive environment, she never has to leave the eggs unless she chooses to. She'll lay her eggs where she believes is ideal for brooding (usually the warm end of her enclosure) and she'll tighten her coils to maintain higher humidity surrounding her eggs. All three of my females this year have pushed aside their bedding laid their eggs directly on the plastic over the heat tape. Two clutches have already hatched and the third is due to hatch in September.