I call it sun rage. When I put my year and half rhino out in his outdoor cage he is as calm as can be for the most part. When its time to come in, he becomes a whole different lizard. Once back in his cage he is fine. SO I have called it sun rage, I have also noticed this with green iguanas as well. It could be they enjoy being outside and just don't want to go back in. Dunno for sure. I am sure someone with more wisdom on the subject will have something else to say or share. Hope this helps
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-Robert

"The difference between 'involvement' and 'commitment' is like an egg-and-ham breakfast: the chicken was 'involved' - the pig was 'committed'."