Understanding anxiety and aggression in dogs and cats

Understanding anxiety and aggression in pets

Why are anxiety and aggression so common in dogs and cats, and how can they be resolved?

About three years ago, our Irish setter Coral developed a fear of thunderstorms. She was seven at the time, and prior to that, she’d completely ignored thunder and even fireworks. We have no idea why her behavior changed, as she was never trapped outside in a storm or experienced any traumatic event associated with thunder. However, several scientific journal articles revealed that when older dogs develop behavior problems, fear or anxiety are the most common1.

In fact, fear and aggression are generally the most frequent problems seen by animal behaviorists1. Whether they actually occur more often than other types of behavior, or whether people just tend to seek help for them more, because of their negative impacts, is not known.

Because fear and anxiety especially can motivate so many different behaviors, including barking, aggression, destructiveness, and house-soiling, it’s not surprising that behavior and training professionals see them so often. On the other hand, it’s also possible that some fear-related problems go unrecognized, because people are not always aware of the signs of stress, anxiety and fear in their dogs or cats. One study revealed that behavior and training professionals with more than ten years of experience were better able to recognize such signs in dogs than people with less experience2.

Every animal can be expected to experience short-lived fearful responses, or even display aggression in rare circumstances. For example, because Coral was previously attacked by an off-leash dog, she will bare her teeth at a dog she doesn’t know well who jumps on her during an initial greeting. But when these behaviors become so frequent or intense that they negatively impact the animal’s quality of life and his relationship with his family, as well as his safety and that of others, they become a problem.

What to do about these behaviors

• A thorough medical evaluation is always warranted, especially for sudden displays of fear or aggression that are out of character for the animal. Pain, disease, or illness can manifest as fear or aggression.

• Despite the varied reasons for fear, anxiety and aggression, they often respond well to behavior modification programs that include counter-conditioning, desensitization, and short-term avoidance of situations or stimuli that trigger the behaviors. While this may sound simple, the actual implementation can be quite complex. Gradual exposure to the eliciting stimuli, while simultaneously managing the animal’s environment to prevent full-blown fear or aggressive reactions, can be problematic.

• An objective evaluation of a dog or cat’s environment, relative to his behavioral needs, and the sources that trigger anxiety or aggression, should be part of the behavior modification plan. It’s probably not realistic, for example, to expect any and all dogs and/or cats to adapt to living peaceably with each other. Sometimes re-homing is the kindest option for a stressed-out animal that is being constantly bullied or harassed by another; conversely, the animal that is causing the stress may also be re-homed.

• Increased physical exercise and opportunities for play may help dogs and cats compensate for environments that contribute to fear and aggression. When Coral is on a walk, for example, and thunder rumbles in the distance, she is much more relaxed and almost oblivious to the sound, as compared to when she is inside with little to distract her. After a storm, a walk or other form of physical activity may help dissipate the biological chemicals released from the adrenal glands as part of the fear response.

• We’ve seen improvements in a percentage of fear and aggression issues caused by relationship problems, when people are instructed to not scold, “correct” or grab for their animal for at least one week. Instead, they must use verbal cues, treats, toys, and other enticements to elicit the behaviors they want. This is combined with using techniques such as a blocking board (an opaque board used to cut off visual contact between the animal and the aggravating stimulus) to prevent unwanted behaviors when necessary.

• In our experience, mild anxiety can respond to homeopathic or naturopathic interventions.

• When an animal’s fear is debilitating or dangerous (including aggression, self-injurious behavior or risky escape/avoidance reactions), veterinarians may prescribe medications that can help, particularly if they’re used in conjunction with behavior modification.

• On a broader scale, the perpetuation of fearful traits and tendencies through breeding practices that don’t consider the future welfare of the animals, and/or that don’t provide adequate socialization in the breeding environment, should be minimized. More attention needs to be given to cat socialization, as well as the socialization of adolescent animals. All these have the potential to help animals become more adaptable and resilient in response to change and unfamiliar experiences.

What causes these issues?

Why some animals develop fear and aggression issues and others do not isn’t fully understood. Behavioral research can shed some light on the issue, as can rational arguments and practical experience.

1. We know that fearful temperaments are significantly influenced by genetics, and that fearful puppies tend to become fearful adults3 (generalized fear tends to persist, often despite intervention). Thus, poor breeding practices are likely one contributing factor.

2. Secondly, while the importance of puppyhood socialization is well known, that doesn’t mean it is widely implemented. Under-socialized puppies, and those that have frightening or traumatic experiences during the sensitive socialization period, are more likely to have fear-related problems as adults.4

Unfortunately, socialization for adolescent dogs has not been promoted, yet many behavior professionals believe that continued socialization during this developmental period is extremely important for stable adult temperaments.

Cats are rarely selectively bred for behavioral traits, and because their sensitive period for socialization occurs at such a young age (two to seven weeks), we believe that many felines are poorly or under-socialized, resulting in excessive fear, and sometimes aggression toward unfamiliar people, other cats, and/or dogs.

3. Another possible reason for the prevalence of fear and aggression is environments that produce ongoing social stress. This has to do with peoples’ expectations and knowledge of the behavioral biology and needs of companion animals. Both cats and dogs in multi-animal households are sometimes forced to live with animals they really can’t get along with.

Dogs have a substantial repertoire of conflict avoidance behaviors, allowing many canines to live peaceably together. But if one dog in the house is a “bully” and doesn’t respond normally to appeasement behaviors from other dogs, social conflict and ongoing aggression and fear often result.

Cats in multi-feline families (and in group housing at shelters) often live in densities that are literally hundreds of times greater than what is seen in freeranging conditions or feral colonies.5 Cats have far fewer conflict avoidance behaviors than dogs do, and rely much more on their environment to provide sufficient hiding places, vertical space, and safe escape routes that allow them to avoid social crowding. No data have been gathered to assess the quality of the environments average household cats live in.

4. A number of scientific papers report that socially confrontational training methods (“scruff shakes” and “alpha rolls”), and those that include corporal punishment, are associated with fearful and aggressive responses from dogs.6

5. A large body of scientific literature about both human and animal behavior documents that unpredictability and lack of control over one’s environment are two of the most common contributing factors to ongoing stress and anxiety.7 People naturally control most aspects of their animals’ lives, but outdated relationship recommendations based on a misunderstanding of social dominance advocate an elevated level of control that is harmful to the well-being of dogs. These include a multitude of rules such as never allowing a dog to initiate play, ignoring him when he wants attention, or not allowing him on the bed or furniture, or to lie in doorways.

When dealing with these problems in a dog or cat, the most important starting point is for the household, veterinarian and other professionals to be able to recognize the signs of stress and anxiety, and when behaviors of all sorts, including aggression, destructiveness and others, are in reality fear-related problems. Understanding and addressing these issues as soon as possible can avoid a lot of heartbreak and ensure your bond stays strong.


1 Landsberg G, Hunthausen W, and Ackerman L. Handbook of Behavior Problems of the Dog and Cat, Second Edition. W. B Saunders, NY, 2003.

2 Wan M, Bolger N, Champagne, FA. “Human perception of fears in dogs varies according to experience with dogs”. PLoS ONE, 7(12), e51775, 2012.

3 Goddard ME, Beilharz, RG. “Genetic and environmental factors affecting the suitability of dogs as guide dogs for the blind”. Theoretical and Applied Genetics, 62: 97-102, 1982.

4 Fox, MW, Stelzner D. “Behavioural fffects of differential early experience in the dog”. Animal Behaviour, 14: 273-281, 1966.

5 Bernstein, PL, Strack, M. “A game of cat and house: spatial patterns and behavior of 14 domestic cats (Felis catus) in the home”. Anthrozoos IX (1): 25-39, 1996.

6 Herron, et al. “Survey of the use and outcome of confrontational and non-confrontational training methods in client-owned dogs showing undesired behaviors”. Applied Animal Behaviour Science, 2009; 117 (1-2): 47 DOI: 10.1016/j.applanim.2008.12.011.

7 Hetts, S. “Psychological wellbeing: conceptual issues, behavioral measures, and implications for dogs”. Vet. Clinics of North America, Small Animal Practice 21: 369-387, 1991.

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