Reptile & Amphibian Forums

Hello,
I understand that hot rocks are generally not a good idea to use because they can burn your reptiles. What I don't understand is why don't the animals move when they feel they are getting too hot on the rock (you know, thermoregulate)? Do they not sense heat easily on their bellies? Is it like when we get a sunburn, we don't know till we already have one?
Thank You

I heard a theory about this which made sense to me. Many lizards (in particular) have thick skin and not a lot of nerves on the outside of it (otherwise they'd be ouching their way across the Australian desert, right?). So by the time the hot rock has left a 3rd degree burn the nerves that are there are short circuited.

Something like that.

It made sense to me, although I'm not enough of a reptile physiologist to say for sure.

The reason lizards do not know when to get off the hot rock is because the heat is coming from below. Lizards are built to take in heat from above. They have a small gland or something on the top of their head that senses heat. When the heat is coming from below, the gland says nothing to the lizard and it will sit there forever. Even if they feel warm in their bellies, the gland says to get warmer. It's like a computer problem. lol
-----
Paullywog

I have no idea what's going on. It's more fun that way.

Not entirely true, the can sense the heat, or why else get on it in the first place? the problem has to do with surface to mass ratio(this comes up alot discuss heat exchange) and radiant heat. A hot rock produce contact heat, not radiant heat therefore an animal has to have a high surface to mass ratio to get thoroughly warmed. Thus smaller animals anole size which have a high surface to mass ratio can use a hot rock to get warm while a larger lizard like an iguana with a much lower surface to mass ratio can never get thoroughly warm and ends up getting burned trying to do so. Some lizards manipulate surface to mass ratio in there favor by having extra skin, or compensate by flattening themselves out. I don't disagree with what has been said, I just thing there is a little more to it. A lizard is looking to heat its core, if no other heat source is available it is willing to burn itself to get that heat. That's how important it is for it to have that core heat. At any rate hot rocks are insuffcient, a radiant heat source is needed for most lizards larger then anole to be able get their core heated.