I have read somewhere that in the wild geckos get their D3 from ambient sunlight, and also apparently they hang out some of their limbs in the morning and evening sun on occasion. I don't know the source of the top of my head though, so I don't know if that's fact. I just read it somewhere. :xNow, leopard geckos being nocturnal do not get much sun light or vitamin D3 from nature....they must get some in the wild and dusk or something. Or do they make their own vitamin D3?