How to get cats to coexist in peace?

Question

My cat is a big neutered male and my sister's cat is a small female. Both cats are three years old. When my sister is away on holidays I have to take care of both cats. Unfortunately, they hiss at each other, are never relaxed, sometimes my cat attacks the smaller one, and though there's no serious damage done (after some meowing he stops), I'm afraid to leave them alone.

This is going on for days and I don't see any considerable progress.

How can I get the two cats to coexist in peace?

Will they eventually learn to tolerate each other, or some cats are just "incompatible"?

I will be minding my sister's cat for about one more week, then they likely won't meet for another year.

Answer 1

Generally, when introducing mature cats to a each other, it's a good idea to put them in adjoining rooms, where they can sniff and hear each other from under the door. It gives them a chance to become familiar with each other, without feeling threatened. The door would then be opened and they would be allowed to be in the same room, but under supervision.

Depending on how this went, they would either be separate into the adjoining rooms for another day and the process would be repeated until they were both relaxed enough to be in the same room without any hissing.

This process can take a number of days (sometimes longer, depending on the cats). So I would recommend doing this, or just keeping them separated for the duration, without introducing them at all. Given there is only another week and they may not meet up for another year, any work that you achieve now will have to be repeated next year from the beginning.

Answer 2

Try keeping your sisters cat in a kennel/carrier (or improvise a cage) where your cat can come visit it eventually they'll get used to each other and be able to get along, especially since they're male and female