Hi- They are gaping, they will open there mouths to cool down. You should check the basking temp, and adjust it if need, move the light up off the cage more if the temp is too high. Is there a gradient temp in the cage? High teps at the basking spot, and lower temps as you move down the cage. Hope this helps!
:Both of my veiled sit under the basking area with there mouth open, what does this mean? Thanks in advance....Cheryl