We have several cats led by a robust 5 year old castrato, they all have grown up with each other and get along together The Boss cat has grown up from a tiny kitten and regards our house as his territory but he is happy to share with the other younger cats.

Our Granddaughter has come back from university bringing her year old femail persian which has grown up without interaction with other cats since sne was a kitten and spending most of her time in granddaughters flat, so she is wary of all humans except granddaughter

Our cats have all tried friendly approaches and been met with hostility, same with humans with the exception of granddaughter.

How can we integrate this hostile stranger? Serious suggestions please.

 

How long has she been there? It takes weeks and often months to introduce a new adult cat to a multicat household. She should be isolated in a separate room for at least the first week or two, and you need to give her plenty of hiding places. During this period, you exchange items of bedding between them so they get used to each other's the smell. Then another 1-2 weeks of very limited interaction through scent, usually either side of a door with a slight gap under it, or doing territory swaps, so one or more of the current cats can go into 'her' room for a bit, while she explores their territory, but make sure the others are kept somewhere else. Then introductions with a barrier, through a baby gate or with her in a crate, where they can see and smell each other but can't actually get to each other. And just keep building on it from there. 

 

This process is going to be MUCH harder on her than on your existing cats. She's been wrenched out of her home environment, dropped into somewhere completely new, with new people and a pack of new cats. Everything about this will be terrifying for her. If you just force her straight into interactions with the other cats (and other people) you are going to completely traumatise her, and she may never integrate. 

What he said is true. Cats aren't like dogs, who are more likely to get along, especially if there are males and females, and it might take some time for them to get along, if they ever do. My daughter has a male (altered) and a female in the house 24/7. They have been there a long time and still don't get along. The male still pees in the house away from the litter box because he can't stand the female's scent there, although he does defecate there. He is still marking his territory even though he's been fixed. They're very territorial in a house or in the wild. The bigger the house you have, the more chance for safety zones she can use.

Many thanks Gents. Keep the suggestions coming.

Thought this was about Bob