suddenly ferocious

Question
Our four house cats have lived together in peace and harmony for 10 years.
All neutered.  The other day, one of them -- Luca, a half-breed Siamese --
had an unfortunate accident falling into a tub of water on our enclosed porch.  
He scampered out, we dried and pampered him, and thought all was well. But
the other three, either sensing his distress or experiencing fear of their own,
suddenly treated him with suspicion. One in particular cannot stop hissing
and growling when Luca approaches.  For his part, Luca is exhibiting high
anxiety and gets extremely tense around the others.  We have had to take
turns isolating him and/or Oscar, also part-Siamese, in a room as even
normally gregarious behavior like eating together can result in a ferocious
brawl.    The growling and hissing has been scary.  This is going on for 2
days.  Any way to bring serenity back ?

Answer
Michael,

Usually that behavior occurs when suddenly one of the cats smells different. Cats go by smell and not by sight, so other cats can think that the cat that suddenly smells different is another cat.

In your case too, with the cats being older, they don't take stress like a younger cat can, and they get confused more easily by sudden changes or events. It also takes them longer to 'get back to normal' when something does occur.

I would try rubbing the other cats with a towel and then rub Luca with it to transfer familiar smells. Some people swear by putting a tiny drop of vanilla on each of the cat's forehead so they all smell the same, though I have never tried it myself.

As Luca grooms he will replace his normal smell, which may take a couple more days, but then everything should be back to normal.

You mentioned eating together is not going well right now. Have you tried giving them some kitty treats together? Something like tuna, or tinned sardines in oil? That helps them to associate something pleasant with each other instead of negative.

Your cats are 56-60 years old in human years and being prepared and knowledgeable about elderly cats will make things easier for the cats and for you. For future reference I am including some very good links about elderly cats. Copy and paste, or type, the whole links into your address bar:

http://www.sniksnak.com/resources/geriatric.html

http://www.messybeast.com/towards-end.htm

http://www.2ndchance.info/oldcat.htm

I hope this helps. And other than that, I hope you had a Merry Christmas.

Tabbi