My cat disappeared for a month

My neutered 2 year old male cat got out and disappeared for a month. We also have another cat who is a 9 month old female. Before his horrible disappearance they were best friends and loved each other. Now after his return they won't get close and keep hissing at each other. He is also acting extra needy, loving, and skinny. My questions are: Why are both of the cats behaving like this? Should I be caring for my cat differently after his return?

Hi, and welcome to TCS

This isn't all that surprising. The most likely reason is that cats are highly scent oriented, and your girl no longer 'recognises' your boy after his absence. This is sometimes even seen after something as simple as a vet visit - that vet smell alone can put other cats right off!

His behavioural changes could also be partly responsible - if he's being extra needy he may well have lost confidence, and anxiety/nervousness in a cat can often make other cats feel very uncertain of them.

Your best option is to separate them for now, and carry out gradual reintroductions, as though they'd never laid eyes on each other before. Rubbing them both down with a little vanilla extract might help too, as it will makes their scents more similar.

Lastly, if you haven't already, do get your boy to the vet for a thorough check up - always advisable after an absence of this kind. It would also be a very good idea to treat him for worms, fleas etc, just in case he's brought any unwanted 'hitchhikers' home with him [article="32680"][/article]

I am glad to hear your baby is home.  I agree with Columbine about this being a scent issue.  I have had this exact same issue recently when one of cats came home after a visit to the vet.  I did not have any vanilla in my house at the time so what I did was take a piece of dirty laundry and rub down all 4 of my cats.  I then wiped down the cat who was being hissed at again.  After this the hissing stopped and things went back to normal.

In this case though I agree that it may be a good idea to separate them and do a re-introduction due to behavioral change in your cat that went missing.  I also agree that he should be taken to the vet for a check-up to make sure there is nothing medical causing the behavioral change. One of my cats got out years ago and went missing for two weeks.  She was acting completely normal and my other cats accepted her as if she had never left.  I still took her to the vet for a check-up.  The vet did not find anything wrong with her other than losing some weight during her time outdoors.  I was glad to have confirmation from the vet that nothing was wrong with my cat.