got a feeling another cat has been in the house and there some strange stains on the back door and on the skirting board upstairs, kind or redish brown, almost like blood.

I dont think it is blood though as it smells of pee, and if my cats had brought in a mouse/rabbit/bird, there would be more than a stain on the wall, there wouldbe the usual carnage of blood and guts/feathers/fur.

So i am thinking a cat has been spraying, maybe its my cat, but he has been neutered, and if its a redish should I be worried?

We’ve recently taken in a 2nd cat and suddenly after a few months our original one has started occasionally spraying inside the house (neutered female). When i had to clean it off the front white pvc door it was yellow, as i assume it’s just urine anyway, i don’t think spray is anything different to pee, it’s just sprayed out to leave a scent rather than just going to the loo when they cover it up.

Tom cat wee is much smellier than normal, they must have some sort of scent glands.

cats have scent glads around the anus, they use this to scent mark territory i believe. Not sure of colour but it is not ordinary urine.

It’s like lilt but dries to the colour of thin treacle on flat surfaces. It’s a pain to get off carpets once it’s dry. It smell awful too like a womens institute, thank goodness mine grew out of it.