New cat smell/meeting question

I was just taking the trash out earlier and I saw the neighborhood cat, Bear (a non-neutered male) outside and he came over to me so I petted him and gave him scritchies. He is a very friendly cat and when I went to go back inside, he followed me in.

Well, I opened my door and my two cats saw him and my male cat, Socks, started hissing and growling at him and Bear was doing the same. Before I showed Bear to Socks, I let Socks sniff Bear's scent and he started meowing loudly and yowling. Is this normal? They both acted like they were going to attack each other...Is this just a male dominance thing? I was too afraid to open the door more than a crack cuz I didn't want Bear and Socks to attack each other.

Meanwhile, Boo, my female (spayed) cat just sat there and really didn't do anything. I thought that was strange.

This is the first time that either of my cats have seen or been near another cat since we got them from the shelter almost 2 years ago.

Hubby and I are moving in a month to a townhouse and I would like to get 2 more cats, but I'm not sure that's a good idea after what I saw today.

Any suggestions, comments...

You say your female was spayed and yet didn't mention if the males were neutered? All cats are territorial and unfixed cats are more so. When you move it is going to stress the cats out quite a bit. I would wait at least 6 months after your move and them gradually add the new kitties to your home.

There are great articles on introdusing cats on this site.

There are ways to introduce a new cat or cats to old cats that will work wonderfully. When you are ready to adopt new cats let us know and we will tell you how to do it right.

Please do not let an unneutered stray cat near your cats. You do not know what diseases he might have, and being unneutered he is likely to attack your cats. It would be very dangerous to do. The aggressive behavior you observed is normal and will not happen if a new cat is introduced correctly to your old cat.

You will find several good threads on introducing a new cat to old cats in the Behavior Forum.

My male cat was nuetered, but I don't think the other male was. I know that the neighborhood cat has his rabies shots, but you're right about not knowing what other diseases he has. I know that Bear is someone's cat because he looks plump, well-groomed and he is very friendly. I don't think that any stray ferals would walk up to people and start rubbing on their leg.

I will make sure to read up on introducing a new cat. And thanks for telling me that I should wait awhile...I was thinking about getting one right away, so that they won't become territorial since they will all be in new territory. But, I guess that it would be good to wait awhile.

I moved this to Behavior.

I have seen my cats respond the same way (thru windows and doors) to wandering unneutered males. One of these I caught, neutered, tested and brought him in the house. There wasn't a single hiss during introductions. I personally think that unneutered males have a scent all their own that other cats, particularly males, respond in a very territorial way.