Once upon a time I used to dread bringing one of my cats home from the vet hospital. Our return often provoked world war 3...
Usually the three of them adore each other, grooming and sleeping together most of the day.
If one had to go to hospital the other two cats would sniff the patient and then hiss and spit at her when we returned. I thought they were reacting to the smell of the hospital or of strange humans and animals. However a recent article says that it is the sudden return of a group member that puts them offside.
In the wild when a cat returns to the colony after a solo meal they hang round on the margins and almost sneak back in when no one is looking. No matter how many times in the day she returns, the group seems to debate whether to accept her back each time.
When I came home from the hospital with a patient, I would plonk her back in the middle of the group and let her out with a fanfare, hoping they would be nice to her if we pushed our way in.
Now I leave her outside and see what the other two are up to. If they are asleep on the bed I sneak the patient into the lounge room, let her out and quickly take the carrier away. If they are up and about I feed them in the laundry and while they are distracted I bring the patient in to the bedroom and let her decide on the best course of action.
Abrupt re-entries are not de rigueur in feline circles. They prefer the more subtle return.