So honestly... I don't know if this is about health or about behaviour, so I figured I'd put it in the general section.
My parents are concerned about their cat. The background of this is that the cat, Lucy, used to be their neighbour's barn cat. The neighbour died, and my parents didn't realize for quite awhile that the cat was still living on the property, so she was on her own for several years. She was never exactly a pet in the first place. By the time they met her, she had become semi-feral. For the past few years they've been feeding her and trying to socialize her, and she's finally at the point where she is willing to come into the house for a few hours at a time.
That's where the question comes in. Something is going on with Lucy, and we can't figure out what. Lately she's been coming in each evening around 6:30 or 7:00 p.m., eventually falling asleep, and then waking up. When she wakes up, she sits there growling, hissing, and twitching her tail. This consistently happens around 9:00, and lasts for an hour to an hour and a half. She does not display this behaviour at any other time. It's like clockwork.
She sometimes lets me handle her. It's iffy, she didn't tonight. Sometimes she does, though, and I checked her pretty thoroughly for injuries and found nothing. She does not appear to be ill.
She just... sits there and hisses and growls. Lucy does not appear to be growling at
us, and will sometimes tolerate petting and even purr right in the middle of it when we interact with her. Then she goes back to the hissing and growling into space.
Lucy had a thorough annual exam on January 8th, and was pronounced in perfect health. All of her vaccinations are up to date. Taking her back to the vet is an option, but it's one I'd prefer to use as a last resort because she finds vet trips extremely traumatic. I'm also not sure what the vet could do for her since she doesn't have any actual symptoms
, and was examined thoroughly very recently.
We're worried, though. Advice, suggestions, and armchair diagnoses would be appreciated.