OnebyOne - I didn't realize that frogs hibernated. I probably learned that in school back in the dark ages, and thenm forgot it. That explains how it survived for at least a month.
A little research can be enlightening! Per google searches, it's likely a tree frog. It seeems that they can hop from a tree onto a roof. There's a toilet vent on the roof, it's uncovered - they have to be or the could become clogged with leaves, etc. So apparently frogs can just fall in. We do have tree frogs around and I have seen them in action on the side of my house, so that is probably what happened.
I had visions of snakes or rats coming through the pipes. Ugh - for three reasons, we'd have to find the break in the pipes, we'd have to fix it, and we'd have to deal with snakes or rats.
It's much more pleasant to think of a frog falling into the vent on the roof. Definitely cheaper than a broken pipe somewhere in the yard.
Tomorrow my DH becomes a frog hunter. He's a city boy, so this ought to be fun to watch. I think hunting for frogs in the toilet is assigned to the husband-ly duties in the fine print of our marriage contract.
Then again, we need to do grocery shopping tomorrow. I think I'd prefer frog hunting to that...