why are my bearded dragons going into what looks like winter

 
Why are my bearded dragons going into what looks like winter shut down in the middle of summer?
i have a ten month old - Spyro - and a two month old - Fluffy - bearded dragon. Fluffy was sold to me as a male but the more i look at its undercarriage he/she appears female. Spyro was sold to me as female but when i look at her undercarriage she has no lumps at all, so i have no clue what she is . both get on great and neither has been aggressive to the other but about a month before i got Fluffy, Spyro started digging and hiding under her rock. she eats fine and loves running around but she spends all her time in her tank under her rock , an hour after her light goes off she does come out and sleep on her stick. i thought that this was just a phase that she was going through but today my two month old has been joining her under her rock. the vivarium is 3 ft by 2ft by 2ft, but i am getting them a four foot tank shorty. please help me because i don't know what i am doing wrong!! i have had bearded dragons before but none of them have acted this way.

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i am not sure what you should do but try talking to someone who knows a lot about reptiles like bearded dragons my friend has a bearded dragon her name is Serra he really likes her um i probably didn't help you a lot but sense i am the only one that took in intrest in those please rate me top contributer o and did you know that when you rate some one top contributer you get three points for your self? well its true:)