It's impossible to estimate how well any particular pair or group of cats will ultimately tolerate each other. Some cats are unusually territorial, may never adjust to sharing their house and may do best in a one-cat family. However, many aggressive problems between cats can be successfully resolved. To do this, you may need help, both from your veterinarian and from an animal-behavior specialist who is knowledgeable in cat behavior. Cats with aggression problems may never be best friends, but can often learn to mutually tolerate each other with a minimum of conflict. Working with aggression problems between family cats will take time and commitment from you. Don't give up without consulting the appropriate experts.

Common Types of Aggressive Behaviors Between Cats

Territorial Aggression: Cats are very territorial, much more so than dogs. Territorial aggression occurs when a cat feels that his territory has been invaded by an intruder. Depending on where your cat spends his time, he may view your whole neighborhood as his territory. Female cats can be just as territorial as males. The behavior patterns in this type of aggression include chasing and ambushing the intruder, as well as hissing and swatting when contact occurs. Territorial problems often occur when a new cat is brought into a household, when a young kitten reaches maturity or when a cat encounters neighborhood cats outside. It's not uncommon for a cat to be territorially aggressive toward one cat in a family, and friendly and tolerant to another.

Intermale Aggression: Adult male cats normally tend to threaten, and sometimes fight with, other males. These behaviors can occur as sexual challenges over a female, or to achieve a relatively high position in the cats'loosely organized social-dominance hierarchy. This type of aggression involves much ritualized body posturing, stalking, staring, yowling and howling. Attacks are usually avoided if one cat "backs down" and walks away. If an attack occurs, the attacker will usually jump forward, directing a bite to the nape of the neck, while the opponent falls to the ground on his back and attempts to bite and scratch the attacker's belly with his hind legs. The cats may roll around biting and screaming, suddenly stop, resume posturing, fight again or walk away. Cats don't usually severely injure each other this way, but you should always check for puncture wounds, which are prone to infection. Intact males are much more likely to fight in this manner than are neutered males.

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