so I just bought a leopard gecko (It's my first reptile) and last night I had turned off it's heat mat. I had read that leopard geckos could withstand temps of 70s (which is the coldest it usually gets in my house). But this morning when I went to go feed it, it was pale and cold to the touch. It's alive, and it caught two of the crickets I put in the tank, but I'm worried for it's health. It's a juvenile leopard gecko.
I do not know a lot about geckos, but my turtle is a poikilothermic animal too. They need the warmth to get going. If they have a low body temperature they can not move fast or with much power. So they need a place to warm up (for my turtle this is the sun-like light bulb on his island) to become fit, i.e. to hunt.
My turtle has his light only shining at daytime, but the water has a thermostat, so it stays in a moderate temperature all the time. A good way to let your animal choose its body temperature itself is to provide a temperature drop over the animals space. For example provide the heat mat on one end of the terrarium and a "cold spot" on the other. So the gecko can choose the distance to the warmth how it fits best.