Those Teeth! - Update
If you read the post Those Teeth! from February 17th, 2014, you may recall this tidbit of information:
... those incisors (teeth) never stop growing.
...they must gnaw everyday to keep their teeth from growing to too long.
In fact, the text books say, if a rodent can't gnaw their teeth can grow right up through the skull of the rodent killing it. This is something I never thought I would see in the wild, because why would a rat not gnaw dooming itself to an ultimate death?
Recently I trapped a live rat who would not let go of the bars on the trap. Upon closer examination I could see why.
This poor rat was missing a lower incisor. The two teeth on the right (viewing the picture) kept each other the proper length and were razor sharp. Without a lower tooth to gnaw against, the upper tooth on the right just kept growing way too long and was actually curling up towards the roof of the rat's mouth.
The tooth had not penetrated the rat's skull, but if the rat had lived it easily could have in a few more weeks. As it was the rat was obviously malnourished and sickly. This rat was humanely euthanized and put out of its misery.
Pack rats and all rodents have amazing teeth. Below is a picture a rock that I found in a pack rats nest. The rats had actually been gnawing on the rock.
The rat managed to take off about 1/8" of rock in a 3"x 5". Maybe chewing on a rock was how the rat I trapped broke off its lower tooth?