It's called "mouth gaping" and, if done for prolonged periods of time, it is indicative of the following:
1. Temperatures too high in the enclosure. (84-88F is normal)
2. Humidity is inadequate. Add moisture, live plants, mist
3. Respiratory infection (most frequent cause. Caused by inadequate temperatures in the most recent past. Bump your cage temps up to 88F round the clock and monitor your dragon. The mouth gaping should cease in a couple of daysif the RI has been caught soon enough. CWD cannot tolerate temperatures much below 70F. Monitor your night-time temps IN THE AREA WHERE YOUR DRAGON SLEEPS and add a night-time heat source if they get below 68F. Keep in mind that warm air rises. If the mouth gaping does not stop OR if you notice nasal discharge or extreme lethargy you must see a vet or you will loose your dragon. RI can and will kill if it is left untreated.
Diane
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dianedfisher@yahoo.com

My 3 CWD-Avanyu, Tripod and Drago