My rabbit is grinding its teeth or chewing somthing but there is nothing in its mouth?

Question
I don't know what to do about this. Ive had this rabbit for about 4 months.It started grinding it's teeth yesterday and hasn't stopped!

Answer
Rabbits tooth grind for a couple of reasons.

There is a happy tooth grind that rabbits sometimes do when they're being petted, or groomed by another rabbit and are very happy.

Then there is another tooth grind that rabbits do when they don't feel good and are in pain.  If they are doing this you may see other signs that the rabbits is in pain.  Often a rabbit in pain will be a little hunched up when it sits and grinds its teeth.  Other times, when they are in pain they just don't move around much.  Sometimes, they are so uncomfortable they will soil themselves by sitting in one spot too long.  Or their appetite may have changed.  

If you see any of those other signs, you should call a vet to have your rabbit checked out.  If your rabbit has changed any eating, drinking, or pooping habits you'll want to tell your vet that.  If you hear a gurgly sound coming from the rabbit's stomach, it may have gas and your vet will need to know.

Basically, if anything else has changed with your rabbit's patterns, your vet will need to know to more easily pin down why your rabbit may be in some discomfort.