Working With an Aggressive Cat

Q: My 7-year-old male domestic shorthaired cat has recently begun to bite me, not on a regular basis, but at times when I least exect it. The last bite became infected and required antibiotics, and I am concerned about this odd new behavior. Why does a cat start biting like this?

A: I am sorry to hear about your kitty’s recent aggression. For the most part, we cats are pretty easy-going. But, sometimes, we can become annoyed and act out.

Aggression by cats toward people can be caused by a number of things, and figuring out its cause can be challenging. With patience, appropriate guidance, and dedication, though, it can usually be successfully managed.

The first step is to make sure that there are no medical causes. Some diseases—hyperthyroidism, osteoarthritis, dental disease, and central nervous system problems—may cause aggression in cats, so consultation with a veterinarian is important.

Once a medical problem has been ruled out, identifying the type of aggression you’re seeing is key to understanding its cause and developing a plan to intervene. There are a number of general categories of aggression in cats, including:

Play Aggression: Most common in young cats that were not raised with littermates and/or do not have appropriate play outlets.

Fear Aggression: Often seen when a cat encounters unfamiliar stimuli—a new person, animal, or noise—or when a cat is exposed to an experience he associates with unpleasant events.

Petting/Grooming-Induced Aggression: May be caused by overstimulation because the person doesn’t pick up on cues of impending aggression and the cat is trying to end the petting. In many cases, visual cues—dilated pupils, tail lashing, and ears moved backward on the head—are observed prior to the cat becoming aggressive.

Redirected Aggression: This type of aggression may be directed toward either a human or another cat when a cat is aroused by some stimulus and cannot address its response to this stimulus directly. For example, the presence of an outdoor or stray cat seen through a window by an indoor cat, loud noises, or an altercation with another cat in the house.

Status-Induced Aggression: Cats may occasionally show signs of aggression toward either people or other pets in situations that suggest that they are attempting to establish social dominance.

Territorial Aggression: Cats tend to establish and defend their territories and may show aggression toward newly introduced cats (and rarely, but occasionally, other animals, or people) that encroach upon their established domain.

Once you have determined, to the best of your ability, what the cause of this aggression is, there are specific recommendations for each type of aggression that you can take to address the problem. While space limitations preclude my addressing strategies for each type, there are general recommendations that apply to all forms:

-Intervene early
-Do not use physical punishment
-Startle the cat, without physical contact, as a way to intervene
-Avoid situations known to stress a cat
-Separate cats that are aggressive toward one another
-Use food treats to reward non-aggressive behavior

In cases that cannot be managed in collaboration with your veterinarian, it may be worthwhile to consult with a veterinary behaviorist. (You can find board-certified veterinary behaviorists at the American College of Veterinary Behaviorists website at

Of course, any cat bites/scratches should be washed immediately with soap and running water, and any signs of swelling, redness, discharge, fever, headache, and/or swelling of lymph nodes in the region of the bite should prompt consultation with a health-care professional.

For more information on feline aggression and how to manage it, please visit the following page on the Cornell Feline Health Center’s website.

Best of luck, and please let us know how things are going when you can.

Warm regards, Elizabeth