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As a new pet rat owner, with previous rodent experience limited to only lab rats, significant time has been spent finding information about these new charges. Favorite rat trivia item: A group of rats is very appropriately called a "mischief".

Some of the folks who are particularly enthusiastic about their beloved rats sometimes make what sound like some pretty strange and far-fetched statements. And some of the what is put forth on the anti-rat, animal control oriented websites also sometimes sounds rather unrealistic. One of the rat "facts" that occasionally has appeared is that rats are able to "flare" their teeth in order to produce a particularly vicious bite. This seemed more in line with the "all rats are vile and vicious" mythology, rather than based in reality.

Rats do have incredibly interesting teeth and amazing chewing power. The word "rodent" after all, comes from the Latin word "rodere" which means "to gnaw". Their jaws are reputed to be able to apply a force per square inch greater even than a great white shark. Rat teeth are also hard, harder than human teeth, and sharp. They have been known to chew through plastic, iron and even cement. The yellow or orangeish coloration in the enamel on those huge front incisors is normal and healthy in a rat, and is from pigment containing iron. And, because the incisors continuously grow and do so at an average of around two to almost three millimeters every week, rats must gnaw to wear them down, which also keeps the teeth sharp. The yellowish enamel on the outer surface of the incisors is harder than the dentin on the other surfaces, so when a rodent gnaws, it wears down less quickly, sharpening the teeth into a chisel-like edge. But still, flaring teeth?

At more than a half an inch in length, the incisors at the front of Eek's lower jaw are already quite impressive. During one of the usual Eek love-fests, while she was laying on her back, especially relaxed with her head lolling, mouth hanging open, huge teeth totally visible, I found that by scratching her jaw in certain areas, her incisors would move and, indeed, actually "flare". Until this time, I had only witnessed them in parallel to each other. When her teeth "flare" apart, they do truly look very wicked.

So it is true. Unlike human anatomy, the lower jaw in a rat is not fused at the center front, but is instead bound by ligaments. This allows a rat to rotate it's jaw slightly in or out, to separate the lower incisors, forming a "V". This is an adaptation related to their eating and gnawing habits.

For even more and explicit details about rat teeth, see this external page. And this external link has beautifully photographed images of rat skulls, including the teeth.

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Blog_post | by Dr. Radut