We have an indoor/outdoor spayed male cat, probably around 4 yrs old (he adopted us, so we are not sure of his age). About a week and a half ago, he started being very unmellow at night -- waking us up with insanely miserable caterwauling, scratching at doors trying to get out. He is outdoors if he wants all day and up to 9 PM or so at night, but he just seems miserable in the wee hours. He does use his litter box, so it's not that. We are miserable as well. We have started locking him out of the bedroom (where he used to love to sleep with us) because of this new behavior. Could he be reacting to a female in heat? He doesn't seem to be in pain, he doesn't flinch or react when we pet him, and he's very loving in the evenings before we go to bed. HELP!

Seems like a normal cat. They're nocturnal y'know.

You also might try increasing the cleanliness of his litter box. I had a cat once who considered the box the Option of Last Resort, the preferred option being yelling and clawing at the door until he couldn't hold it anymore. The box had to be pristine.

Cats are night time creatures. Sometimes it's a full moon that drives them outside. I agree its normal behaviour. Box prestine yes but not cleaned with chemicals or he won't use it either.

I have had a cat do the nocturnal, wake you up thing. I opened the bedroom door and screamed and danced insanely. The cat quit waking me up as my behavior frightened it.