My mouse started becoming listless just before I left Oregon. Since my mother had scheduled an appointment with the veterinarian for her cats, I had her include the mouse, so it could get checked out as well. The vet was a little surprised. He thought that Mousey was the name of a third cat and not an actual mouse. Apparently here in Indiana, not many people take their mice to the vet. He said that he sees a mice perhaps once every couple years. This was clearly a bit outside his area. He referred to the mouse as a him, and I explained that it was female. He was pretty sure it had a penis, though, but then he left the room to get a book with a diagram of mouse genitalia. He said that it was probably female after all, since the book said that a mice os that age would have prominent testes, which it did not.
He looked pretty grim as he examined the mouse and felt its belly. He said there was noticable swelling, which indicated a probable tumor, since there was no sign of infection. Apparently there is very little that can be done for mice. Then I raised the possibility that it might be pregnant, since there is that wild mouse that sometimes gets into the cage with it. He said that that was also a possibility but that he couldn't tell, since he had no experience feeling up pregnant mice. He looked up mouse gestation, and it only takes three weeks, so that could not be ruled out. That night the mouse started panting and proppped itself up on its dish with one paw. The next morning I found it dead in the same place.
In any event, I'm glad I got it to the vet before it died, so at least I know nothing could have been done. For the first time in a long time, I am mouse-free. This means that at the end of the summer, I will not have to worry about the logistics of transporting a small rodent with me to the west coast, sneaking it into hotel rooms and keeping it at a non-lethal temperature throughout the trip. Also, I don't have to worry about sneaking it into my dorm room and keeping it hidden from sight for an entire school year.