Gerbil with leg thumping

Question
Our 12-month old gerbil has started eating the plastic shelves in her cage.  Since she has been doing this, she now has an uncontrolled leg thumping problem.  We thought she was running on her wheel, but we watched her and while sitting still her leg started thumping.  Is she ill or could she have a vitamin deficiency?  She is still eating, drinking, and moving, but the behavior is concerning.  What do you think?

Thanks.

Answer
Well hello!! Your gerbil is perfectly fine. The leg thumping is a basic behavior of gerbils. Leg thumping can be a sexual display or just for fun. It's completely normal. It's more than likely that she's doing it just for practice. It's funny to watch them do it. They do it to say look what I can do!! *thump* *thump*