Cats are territorial, which means they are not crazy about sharing.

They don't like sharing anything a cat uses or enjoys, including food and water bowls, litter boxes, scratching posts, resting and climbing areas, toys, and the attention of the people in the home.

To prevent problems, go overboard in adding feline favorites when you add a new cat to your family.

Don't put everything in one location. Instead, spread resources throughout the house. If needed, give one cat a "sacred" room that is off-limits to the others.

Cats are individuals. The more you can pay attention to body language and daily behaviors, the better you will be at making any helpful adjustments. Ears back, tails tucked or tense muscles mean a cat who's not happy sharing.

Animal behavior experts Susan and Roland Tripp are the authors of "On Good Behavior." For more information, visit their Web site at AnimalBehavior.net.