Cats are not friends by nature. We need to take that into account.

Cats meeting for the first time are natural enemies. They have sharp teeth and claws that are more than enough to injure their opponent life-threateningly.

In the wild, cats don't need each other to survive and haven't evolved as group animals. This doesn't mean they can't form strong friendships with other cats, but those can only develop under strict conditions, such as an optimised environment with enough eating and hiding spots, and a very slow, gradual introduction between cats that didn't grow up together.

TIP 1 - Cats want to do everything alone

Make sure your cats can do everything on their own in the house. This means all their essential resources - food, water, litter boxes, sleeping spots, scratching spots, heights, hiding boxes and so on - are spread out enough throughout the house, so they can choose their territory without having to run into the other cats.

When you arrange your home this way, you create the best situation for your cats to tolerate each other and maybe even become friends, simply because there's enough for everyone. A sense of abundance creates a feeling of safety and control, while a sense of scarcity has exactly the opposite effect.

TIP 2 - Never just put two cats together

For many years, a lot of very wrong advice has been circulating, such as 'put your cats together in a crate and let them fight it out', or 'just let them fight it out and they'll learn their place'. Here's why this is so wrong.

Cats are solitary hunters by nature and aren't equipped with an extensive repertoire of social communication signals or reconciliation behaviour. In the wild they simply avoid each other, they don't say sorry to one another, and they don't make up after a fight.

Scientific research shows that wild colonies of cats consist of related females who come together to care for the kittens as a group.

We often put cats together who aren't related, who are neutered, and who never chose each other in a natural way. That's why we need to be extra careful with the introduction.

TIP 3 - Introduce through training

Coming home with a new cat is a hugely threatening situation for both parties, so you never want to simply come home and release the new cat from the carrier in the middle of the living room, which sadly happens so often.

We get it - you can't wait for your cat to meet her new friend, but you really have to stay strong here: keep the new cat separate, expand the environment with more essential resources, make sure the new cat can fully explore the new surroundings without contact with the existing cat, and only start the gradual introduction once both cats are completely at ease.

TIP 4 - Avoid unfamiliar cats looking in

Unfamiliar cats looking into the house, often through floor-to-ceiling windows, is one of the biggest causes of spraying and anxious behaviour indoors. Sometimes it goes even further, with strange cats managing to get in through the cat flap to terrorise the resident cats in their own home. That is downright traumatic.

Staring and making eye contact is extremely threatening to cats and must be avoided at all times. The best trick for this is to cover the bottom 60 cm of floor-to-ceiling windows (the width of the roll) with translucent film. This way the cats always feel safe as they move through the house.

Of course they can still look outside, but only from a height, no longer at eye level. So place scratching posts, cat trees, tables and sofas in front of the window, so you force them to go up high when they want to look outside. Looking out from a height makes potential threats feel less threatening to them.