I've updated this shot a little bit from my last post. In that post I mentioned that we had a screening and a classmate suggested to add a little to the arc to the rat's leg when it stretches. It was something that I didn't really think of but I think it looks a lot better since it no longer looks like the rat just stretches his leg from nowhere.  

In this new version he brings his leg up in anticipation of the stretch. It's only a subtle difference but it does help sell the action.