Do cats hallucinate?

27 May 2025: When I got home from trivia a bit ago, Jo was chasing something around the house quite insistently. But I didn't see anything. She would stop for a bit, then take off again, agitated as heck. But still, I couldn't see anything. I was like, "Ummm...is she seeing something that isn't there?" Was she hallucinating? 

And then I went into a mini-spiral: is it because she only has one eye? Is it because she's sick? She did sneeze a time or two and had a little more sleep in her eye than usual? And if she is seeing things, what does that mean? 

Never was more relieved when an actual fly moved through the room. Whew! 

(It even dive-bombed my head as I typed this; I suspect she's already made contact with it and it isn't at full-abiilties!)

And, yes: they can hallucinate, apparently, but she wasn't.