Odd behaviour?

[immortalspuddy]

I have two pairs of White's, one pair is in a large viv, and the other two are new additions that are still in quarantine.
However in the past few days I have noticed that both pairs, even in their separate vivs, have this thing where they climb to the top of their viv, and try and get onto the roof, which of course they can't grip onto and then fall off.
I have never seen this before.
Of course I know they like to climb, but they keep falling and I am worried they will hurt themselves.