Ornate uro, had him about eight months. Most afternoons he sits directly under the basking lamp with his mouth hanging open. He is alert, eats like a horse, closes it the moment he wanders off to the cool end.
Everything I read about open mouths in reptiles is about respiratory infections, which has made me jumpy. But he only does it while basking. Am I looking at a lizard regulating his temperature or the start of something?
That is thermoregulation and you have already described the two things that make it so. It happens while basking, and he shuts it when he moves to the cool end.
Uros want a basking spot hotter than most pet lizards get, and once they are up to temperature they vent a bit of heat through an open mouth. The version that worries me is a gaping lizard everywhere in the enclosure, including the cool side, because that means there is no cool side and the whole box is too hot.
Cool end reads 29C on the stick-on dial on the glass, which I assumed was fine.
@tail_whip_warning · 17m ago
There is a second normal version worth knowing so you do not mistake it for distress. An uro that feels threatened will open its mouth, puff up, hiss and whip that spiny tail at you, usually while backing into a corner.
The giveaway is that it happens when you approach or reach in, not while he is lying under the lamp. Mine does the full display if I move too fast past the glass and then goes straight back to basking.
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