In the PC and Console versions, The Sims: Unleashed, The Sims 2: Pets, and The Sims 3: Pets, they are one of the main parts of the game, in that they must be fed, given attention, played with, cleaned up after, and watched over.
The Sims: UnleashedEdit
Cats were introduced in The Sims: Unleashed. In The Sims, a family can adopt a cat by going to the Pet Center in Old Town, or a Sim can befriend and adopt a stray. The Create a Sim section of The Sims does not allow players to create pets.
The premade cats belonging to playable households in The Sims: Unleashed are:
The Sims 2: PetsEdit
In The Sims 2: Pets, cats also must be trained so they can live with Sims. The player can do this by scolding them if they don't want them to do something that is bad, e.g., destroying furniture, or by praising them to encourage a behavior. For example, cats can be trained to be filthy or clean, and cats may get up on tables to eat Sim food unless they have been trained to prefer pet food or to stay off furniture.
Unlike their counterparts in Unleashed, kittens in Pets are mobile and largely self-sufficient. They can feed themselves (provided there is food available) and sleep on pet beds without the help of a Sim or their mother. Kittens can also learn Behaviors. However, they cannot go up or down stairs without the help of a Sim and they cannot get jobs or learn Commands.
The premade cats belonging to playable households in The Sims 2: Pets are:
The Sims 3: PetsEdit
Cats return in the fifth expansion pack for The Sims 3, The Sims 3: Pets. Like Sims, cats have traits of their own. Initially, they are assigned three traits . Unlike The Sims 2: Pets, cats have only six needs: Hunger, Bladder, Energy, Social, Fun, and Scratching 
Cats are able to hunt for and bring home collectables that a Sim can keep in terrariums or send off to the science facility. Cats with the Hunter trait are especially adept at this, but all cats must first be trained. They will then develop hunting as a skill, which they can level up as they get better at it. The higher level Hunter a cat is, the more likely it is that it will catch something other than leaves, feathers, or snake skin. A trailer for the console version of the game shows a cat banishing a ghost from the lot.
Cats, like dogs, can develop traits. This means that even though a cat is not born or made with a certain trait, it may develop it over the course of its life. For example, a cat that plays with toys often can develop the Playful trait, or a cat that grooms him/herself often might develop the Neat trait.
Cats can breed if a pet house is present, and will give birth to several kittens if there are not already more than 8 Sims in the household. In order to have a larger litter of kittens, Sims may buy the lifetime reward "Fertility Treatment for Cats." It takes about 4 days from conception till the kittens are born. Whenever a cat becomes pregnant, the same music that sounds for Sims will be played. Kittens are not able to do things that adult cats can, such as climbing stairs and playing with toys.
- There are over 30 cat breeds on the console version of The Sims 3: Pets, and over 40 cat breeds on the PC/Mac.
- You must have a Sim in a household with animals; they cannot live alone.
- You can adjust the lifespan of the cats the same way you can adjust the Sims' lifespans.
- Cats may react negatively to the TV but can howl along with music.
- Cats can vomit on the floor, due to a furball in their throat, if they only groom themselves. Your sim can brush them to avoid this.