Outside cats like the warmth of the engine block under the hood of your car. So they often crawl in there. They used to say when I was a kid, to always remember to honk your horn once as you are about to start your car. I don't know if that works, because I've never seen anyone do that.
With today's cars, a mouse would hardly fit in the spare space. Most cars have a floor plate sealing the space off as part of the sound insulation. On a cold night, our cat just used to wait for Jane to fall asleep, then sneak in under the duvet between us. He was not stupid, he knew that if Jane was awake he would have been kicked out.
PSA: All Cats are Furry Assassins... Signs that your Cat wants to Kill You: -------------------------------------------------- Sign #1: Increased aggression Sign #2: Staring Sign #3: Hiding and ambushing Sign #4: Unusual vocalizations Sign #5: Destructive behavior Sign #6: Lack of affection Sign #7: Sabotaging your efforts
More general advice on cats: Planning ahead with a cat is a good idea always. Like with a kid ask questions. Like with a kid, you ask how old will I be when he is in college? And cats on average live longer than dogs. Parrots and turtles live to be over a hundred, they say. So getting an older cat might be a good choice, if you are elderly yourself. He may die before you do. Which might be good, because then you won't have to worry about making sure someone takes care of him after you.
