A large number of cat owners have more than one cat. There are varying reasons for this, and the reasons will often dictate the dynamic. Sometimes in a household, even though the pets are nominally a family animal, you will find that a cat (or a dog for that matter) is often referred to as being attached to a specific member of the family. For this reason, sometimes a family will get more pets so that everyone has their “own”. This doesn’t always work out.
Another reason for getting more pets is that people find that a cat will be more content if it has a playmate. This theory works, up to a point, but anyone who has introduced a new cat into a household where one already exists will know that there are some drawbacks to the theory. Namely that if you introduce a new cat onto an older cat’s “turf”, the older one will not willingly give up any of its space.
Usually, though, a cat will eventually welcome a new pet into the house and will begin to form a bond with it. This helps training because – along with the increased contentment of having a “prowling partner” – each cat will be a lot more keen to follow instructions if they see that their fellow cat is doing the same and not having any problems as a result. Indeed, in many ways you are “leading by example” because a cat who recognizes the right way to act – through witnessing it in another – will be quicker to pick it up.