I had a female cat that on a couple of occasions made growling sounds to indicate some presence. My (watch cat) haha. I think it was noises outside but I didn't hear anything. I am pretty certain that cats have a higher level if perception and perceive much more than we can see. I think it is so common place though for them to see spirits, if you will, that they simply accept them as normal to be around, but do focus on them occasionally. Its a far out conception I know, but the way cats behave like they are intently looking at something we can't see makes it a possibility.
Glad you bought this up G.S.
Growing up I have mainly had cats, but after I moved out on my own I have had dogs and cats.
The cats were mainly Toms, but dog wise they were primarily females and always one male.
I noticed that during the times of "Boogativity" as I call Visitations by (Spirits, ETs, and UTs. EDs, Nonts, etc.) It was always the females that, even before they materialized, first noticed their presence.
Late in 2009 as I was moping at my computer trying to distract myself, my Chow-Chow Fox whom lay by my bed room door where my male Wire Hair Pitbull Mix Terrier Shadey-Boi lay dying of old age (20 years old), suddenly emitted a deep growl and charged at the empty air before what I call my "Guess Room."
I call it that for it seems that, that room is some kind of Vortex or Portal, and you have to guess what the hell you will walk in on when entering there at times, because of that its door is kept locked and behind an iron gate, which is also locked.
Anyway Fox just stood there her fur raised, eyes squinting, ears laid back and snarling as if she was challenging someone or thing that just came out of my music studio room, which was next to the Guess Room, which is now also locked behind an iron gate.
Her eyes were focused on a certain point in the air about seven feet in the air.
Needless to say these actions scared and was scaring the hell out of me.
I called to her telling her it was OK, and for her to come lay by me.
She obeyed, but a moment later did the same thing, again stopping at the same point looking at that same area.
I called her again a little more voluminously not out of anger but more so out of rising fear on my behalf, and told her to lay and stay by me.
She did as I told her with that grumbling complaining sound that dogs do when they are upset.
I figured she had just called me a 'Stupid Human" in Doganese.
It had been a bad year for me, I'd just lost my leg, my Mom, and now my dog was dying, I did not need Fox freaking out every other minute.
Again I tried burying my thoughts in the copious E-mail I had accumulated while I was hospitalized.
Fox again suddenly jumped up growling and charged the same area.
This time I turned and began scanning the area shouting at the Unseen Intruder I was now convinced was there.
"Who ever, what ever, why ever you are here, get the fuck out of my home!
You were not invoked or invited here by my thoughts, actions, or deeds, and so you are uncalled for, undesired, unwelcome, and so will find no nesting place here! You will not touch my animals, my possessions or me as you leave! With this I cast you out!"
I then pleaded the blood as my Mother and sister had taught me to do, the air seemed to become clearer, and lighter.
Fox returned to my bedroom and laid beside Shade, the next morning as I was petting him he "slept away" from us.
Fox has never done that again.