Why Does my Rat Grind Its Teeth?

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If you've got a pet rat, you may have heard some grinding sounds originating from your pet's cage. You may even find him chewing on the metal bars! If you've ever wondered why a rat constantly grinds its teeth and is constantly chewing, then keep reading!


Chisel-Like Teeth

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A rat's incisors are much like chisels. The cutting edge is a hard yellow enamel on the outside with the rest of the tooth being a softer and whiter dentine. Overgrown teeth present a problem if not properly worn down and this is one the reasons rats grind their teeth.



Rats produce a grinding sound with their incisors. This process is called bruxing or chattering and results from rats having to wear their teeth down because their incisors are in a continuous growth stage.


Eye Boggling

Sometimes during bruxing, a rat's eyes may vibrate rapidly in and out of their eye sockets and thus cause a rather disturbing sight for the uninitiated! This is called 'eye boggling' and the reason this occurs is purely anatomical. You see, the rat's lower jaw is pulled up by a part of a muscle that passes through the eye socket in back of the eyeball. During teeth grinding, a rat moves its lower jaw up and down rapidly. The contractions of the jaw muscle vibrate the eyeball in and out of the socket in conjunction with the jaw. Intense bruxing is associated with eye boggling and also occurs at times of great relaxation and contentment, akin to a cat's purr.


Other Reasons For Bruxing

At times, fighting male rats will brux accompanied by hisses, puffed out fur, and laid back ears. This bruxing is much louder than contentment bruxing and is done to threaten their opponent.


Rats also grind their teeth in times of stress and pain. Intense interactions with other pets may cause this action as would a visit to the vet's office (though, vet checkup time seems to affect all pets in some manner!) .




Rats are able to chew on things throughout their lives without wearing their teeth down to the gum line due to their ever-growing incisors. Of course this also means rats must continue using their teeth in a gnawing and grinding fashion so they don't grow too long. The rubbing and wearing down of teeth, as well as sharpening them, is the results of a process known as thegosis.


Chewing Fallacies

Incidentally, rats do not require wood or hard surfaces to chew on in order to keep their teeth in check. This is a common fallacy. Teeth overgrow only if there is a medical problem preventing normal teeth grinding. In normal rats, their upper and lower teeth remain sharp, lined up and at the proper length by teeth grinding.


Check Your Rat's Teeth!

Take note that if a rat's tooth is knocked out of alignment, both teeth will grow too long and cause health problems like rubbing open sores in the mouth, possible infection, weight loss and even death!

Every rat owner should periodically check their pet's teeth for normal growth. If your rat's teeth are unevenly worn or missing, the incisors must be checked to see if trimming is required.

By Tom Matteo

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Fat Rat Central: Why Do Rats Grind Their Teeth?
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The Rat Fan Club:Overgrown Teeth

About the Author
Tom Matteo has been a freelance writer since 1992. He specializes in hardware and software reviews for computers and gaming systems, and occasionally writes about such topics as animal behavior and care. Tom resides in Bethlehem, PA with his wife Tina and his beloved cockapoo, Angel.


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