Jumping

[Jessica Pierson]

Hi everyone,
     I have a quick question about Nape's behavior.  Every once in awhile
he'll jump in his aquarium, straight up, and actually hit his head on the
cover!!  He doesn't do this very often, I've only witnessed it a couple of
times.  Does anyone have any idea of what he's doing??  Is this a signal to
me, that he wants to come out and play?  Or is he really trying to get out??
Is he unhappy?  Any insight you could lend would be appreciated :)

-Jess
(and Nape and Indy!)