Today @ Colorado State has been replaced by SOURCE. This site exists as an archive of Today @ Colorado State stories between January 1, 2009 and September 8, 2014.

Veterinary Medicine

Animal Behavior Column: What to do when cats are aggressive

January 31, 2012

There are more cats living in American households than dogs, and they usually don't live alone.

catMost cat homes have multiple cats. When cats don’t get along, that is a source of stress not only for the cats involved, but also for their owners. The top two reasons for cats being relinquished are aggression and elimination problems, and sometimes the two can be intertwined.

Subtle signs of aggression

Almost all acts of aggression between cats are resolved without actual fighting. Cats are subtle and a lot of behavior can go unnoticed by owners. Stress can build over years and erupt, seemingly suddenly, into a huge problem. Watch for these subtle signs of brewing aggression:

  1. Staring can be a common form of aggressive display. Watch for the other cat’s behavior in response to staring. Do they stop what they are doing? Do they turn around? Then this staring is a form of control one cat uses over the other.
  2. Choice of resting spot can be a clue to what is going on. Often an aggressor cat will lay in open areas that allow them access to important resources, such as food and water bowls, litterboxes or access to outdoors. These cats may appear at rest, but their ears may be partly pinned and their tail may be switching or flicking.
  3. Change of behavior on the part of the recipient cat. Cats that are the receiver of daily stressful communications can show changes in weight, grooming behavior and litterbox habits. They may startle more easily and change where they prefer to lay, sleep or play based on the behavior of another cat. These are subtle signs of avoidance. Sometimes these cats become exclusively active at night when the other cat is not.

So when do owners typically notice a problem?

  • When their cats are actually fighting. Hissing, chasing, clawing and biting are usually obvious signals that there is a problem. Sometimes owners misconstrue this behavior for playing. A good question to ask when trying to distinguish this is: “Does the recipient come back for more?” If there is no give and take, then it is probably not play.
  • When one or more cats experiences a litter box problem. Hiding and avoidance can play into why especially victim cats may start to inappropriately eliminate. This problem is inextricably intertwined with healing the rift between the cats.

Treating aggression

Owners are often misinformed that aggression between cats is a problem that cannot be solved. Treatment of inter-cat aggression is highly individual to the cats involved, but is something that can be resolved well. Ideally, it is best to work on the problem before it progresses to more serious displays of aggression. If you see warning signs of aggression between your cats, don’t wait to get help from your veterinarian or an animal behaviorist. There are many more choices for treatment when the cats are not aggressive on sight. Cats can live together in harmony.

Dr. Jennie Willis is an animal behavior instructor at Colorado State University and owns a private consulting business, which provides counseling for problem pets and their people. 


Contact: Dell Rae Moellenberg
Phone: (970) 491-6009