Puffing up and opening mouth?

[LIZZIE82]

They are well fed and look it.

[UncleChester]

Could they be shedding? They puff up from side to side and open their mouths wide repeatedly. The puffing up seems to stretch and loosen the skin, the open mouth is eating their shed skin (you can see it in the corners of their mouths if you look closely). The result afterwards is a shiny new looking frog.

Come to think of it, I've never seen my American Green Treefrog do this but I've caught many Gray treefrogs in the act. I assume American Greens will do it as well?

[LIZZIE82]

Maybe. She is growing so I assume that she may be getting some new skin.

[wesleybrouwer]

Maybe. She is growing so I assume that she may be getting some new skin.

Frogs, unlike reptiles, don't shed particularly to grow.
A frog is able to breed trough the skin, so it's important to keep it in top shape.
Therefore a frog will shed it's skin every day and eat it, not only when growing up