As you finally get to at the bottom of all that, The Mouse House is behind him. ;)

Another factor here you don't mention is the popularity of rats and other rodents as pets. You personally may be skeezed out by them, but everyone else isn't. My eldest son has one we inherited from a science class and he's turned out to be a great pet. He's quiet, personable, cheap to keep, and eminently trainable (he comes when he's called, he's litter trained, and he has a repetoire of tricks). He's a portly old sucker at 3 years old, and I'm going to be sad when he's gone.