Since we're talking about rats, thought I'd share my recent rat experience. It may help anyone thinking of car dwelling in a Prius. I took my car in for service and they told me they found rat droppings in the air filter. The service guy asked if I lived in the hills, since that's a common problem they see. I don't, but I live in the high desert, so a rat isn't beyond the realm of possibility. However the car is garaged so don't know how it would have got in.
For whatever reason I couldn't do anything about it that night. I happened to have picked up a pack of mentos and it must have fallen out of my the bag onto the floor of the front seat. When I got in my car the next morning, if I had any doubt there was a rat, it was gone because the pack of mentos had been gnawed too shreds.
The posters talking about creep factor are right! I wanted that thing dead and gone and my morning commute I was trying not to think about it possibly living in the car and making the commute with me just a few feet away from me.
That night after work, I wasn't messing around. Picked up 3 different kinds of traps, placed five total around the garage, a glue trap near the tire I'm assuming it used to scramble into the engine compartment, and one trap on the passenger seat floor.
I did some milling around the house and garage, checking the traps somewhat obsessively. I don't know when rats are active but I wasn't really expecting to catch anything until morning. However, around 8pm, when i checked the trap inside my car, it was flipped over and had the bottom half of a rat sticking I out of it including a long, leathery rat tail at least as long as it's body.
I put on some thick chemical gloves and picked the trap up as gingerly as I could and tried not to look at the damn thing while I threw it in the trash. But I caught a look at its black, beady eye, lifeless, but staring at me all the same.
Bleh! Man, I do not want to repeat that experience! I'd never heard of rats getting into cars before this experience, but yeah I guess it makes sense. Rats seek the warmth of the engineer winter. I don't know if car manufacturers take precautions against this or if it's preventable at all... But FYI form Prius dwellers, this may be something you want to watch out for.