Do you wish your four-pawed friend to have a best friend? Old and new kitties cuddling together is the dream, and it may seem an excellent idea to bring a companion home for your pet cat. However, not every kitty will be thrilled when the newcomer moves in, and experts say a slow and steady approach works best.

"Cats are creatures of habit," says animal welfare activist Hester Pommerening, "and they can react sensitively to changes."

So how do you successfully help the two house cats get to know each other – and which tools and tricks make it easier for the new cat to move in?

Here are some of the most important questions and answers.

"Can I just bring the new cat into the flat?" That's not a good idea. "If you just let two cats clash in the existing cat's territory, you're likely to get just that – the cash," says Sarah Ross from the animal welfare organization Four Paws." It can work well to present the cats with a fait accompli, but it's a high-risk strategy, says Michaela Asmuss, a cat behavior therapist from western Germany. For the newcomer, the move means stress, while the long-established animal may feel threatened in its territory.

"Should the two cats be kept apart, to begin with?" "When socializing, it is essential to give the two cats time to get to know each other in peace and not to overtax them by simply putting them together," advises Pommerening. "And that means, for example, that the cats don't necessarily get to see each other but are allowed to get used to each other's scent first."

In the beginning, it makes sense to put the newcomer in a separate room – with the door closed and with its litter tray, food, and water bowl. If you have a one-room flat, you could make the kitchen your cat's home for a short time, says Sarah Ross. She says you can then gradually introduce them to each other by "swapping towels, cloths that the cat has been lying on so that each can sniff the other."

Cat owners should also pay careful attention to their pets' reactions. Possible warning signals include the new cat immediately peeing on the strange-smelling cat blanket. "If that happens, I would immediately consider whether it makes sense to let this cat move in," says Asmuss.

How do I bring the two cats together? At first, it's best to do it briefly and under supervision. "The first encounters should always take place in such a way that the cats can't jump on each other directly but that there is a screen between them," Asmuss recommends. For example, you can put a baby gate in the door frame and stretch a cat net between the bars. You could also stretch chicken wire or cat netting into a wooden frame and use it as a substitute for a door. Don't be alarmed by hissing at the barred door. "Hissing is always defensive and is quite a normal reaction for the average cat," says Asmuss.

How useful are rewards when getting to know each other? Cat owners should make the introduction as positive as possible for both animals. This can mean giving the cats treats when they meet. Clicker training can also be a good idea if the animals are familiar. Pheromones – messenger substances released into the air with the help of a vaporizer – may also be used. Pommerening believes they can help to reduce stress in cats.

When can the cats come together without a separating grid? "When the cats can see each other through a grid and are interested in each other and also show positive signals," advises Pommerening. For cat behavior therapist Asmuss, a raised tail and friendly greetings with the nose are good signs. However, you should still be prepared for minor conflicts and separate the cats when you can't supervise them.

Does each cat need its litter tray permanently? Yes, and it is even better to have three litter boxes, according to the experts, because, as Pommerening explains, "cats like to defecate and urinate in separate places." She also advises offering food and water in separate bowls "so that the cats can stay out of each other's way and feel they have their own place where the other cat doesn't dispute their food or water.