I have a 14 yr female cat who, for the last almost 2 years, yowls like clockwork around 10pm at night every night. Last year I thought it might be a thyroid issue but her physical exams are consistently good and blood work showed a healthy thyroid. Her eyesight seems good and she is completely normal during the day.

For background we have one other female cat who we were told was her littermate when we adopted them together but they hate each other and usually try and steer clear or. Our yowling cat tends to spend most of her time downstairs while our other cat stays upstairs. Non-yowling cat sleeps on the bed with my husband and I every night. We’ve started to leave a night light on for the yowling cat because I’ve read that the dark might disorient older cats but it does not seem to be working at all.

I don’t know if the yowling is jealousy, dementia, or something else but it is SO loud and can last for awhile off and on for up to an hour. I’m at a loss…

Any advice?