Royal Python

[Hannah]

I bought a royal python at the end of the summer when he was 4 months and he was very active and up until mid November.
He used to come to the front of the viv and enjoyed winding the cats up by dancing for them, when i sat by the viv he would stretch out and touch the glass so his nose would be by mine.
He is a friendly snake he has never bitten any of us and we have had no problems with him apart from when he had mites for 2 weeks.
For the past month and a half he has started to spend 95% of his time in the hide.
Is this some form of hibernation or is he simply getting older and no-longer feels the need to go out and about?
He is my first python so i am very new to this.