Last night while we were playing in my bed, Van Gogh climbed up onto my chest, laid down inside my shirt, and began happily bruxing and boggling. For a new rat owner, or someone who’s never seen this behavior, it can be very strange, and perhaps even scary. So what is bruxing and boggling, and why do they do this?
Bruxing is when your rat grinds its incisors repetively against each other. This is a behavior that serves the benefit of sharpening the incisors. Like a cat’s purring, bruxing can occur for many different reasons including relaxation, stress, and illness — but is mostly a sign of a happy, relaxed rat. It’s important to pay attention to the body language of your rat to understand why he may be bruxing. Last night when Van Gogh climbed up on me, ready to fall asleep, he was certainly bruxing out of relaxation. If you find that your rat has frozen in place, is very tense, or lethargic he may be bruxing from stress or illness.
Excessive bruxing can sometimes be a sign of a pituatary tumor. If your rat is bruxing a lot, and also seems to be rather clumsy and has trouble holding food in his front paws, be sure to take him to an exotic animal vet to rule out something more serious.
Bruxing can also occur for no other reason than maintaining their teeth. Rats’ teeth never stop growing, and in order to prevent them from becoming too long, your rat will grind them down.
Boggling is a behavior which goes hand in hand with bruxing. In fancy rats, the masseter muscle passes behind the eyeball and is what moves the jaw up and down during bruxing. When your rat is bruxing intenseley, the muscle can cause the eyeball to vibrate, making it look like it’s popping in and out of your rat’s eye socket. Although this can look strange and scary if you’ve never seen it before, it’s perfectly normal and nothing to be concerned about. It’s widely accepted that boggling occurs when a rat is especially calm and relaxed.