Tail chasing, at first glance, may appear to be a normal component of play behaviour in dogs. Problems arise when such behaviour becomes excessive and the dog injures itself during the activity and when the dog cannot be distracted for other activities. Many would define tail chasing, or whirling, as a stereotypic behavior. Stereotypic behavior can be defined as a ritualistic, repetitive, constant sequence of movements appearing to serve no obvious function. Such behavior is often found in cases where animals are confined and where their behavior is restricted, but can be present in ordinary environments, as well.
The primary causes of excessive tail chasing often involve aspects of learned behavior or medical problems or both.
Tail chasing and other stereotypic behaviors may be a result of operant conditioning, a process by which a behavior is affected by its consequences and an association is made between a stimulus and a response. Because dogs are social animals, attention from the owner is often a positive reinforcer causing an increase in the frequency of the performed behavior whether the owner intends this or not. Even adversive attention may act as a positive reinforcer of the behavior, especially when the animal receives little owner attention in the first place. In this case, any attention the dog receives is highly rewarding. This type of behavior is known as "attention-seeking behavior".
Boredom is another postulated cause of some stereotypies, but an unlikely one. A diagnosis of boredom as a cause of stereotypic behaviour can be incorrectly assumed. In fact the animal may simply have a greater need for aerobic exercise and will cease energy consuming stereotypic behaviour when activity is normal. It is not boredom per se that is the problem, but lack of exercise.
In addition, some dogs with anxiety may chase their tail as well. This anxiety may be in response to some sort of stimulus or it may be nonspecific. Sometimes if a dog has had a previous injury to an extremity, it may start chasing that region when it becomes aware of it. Such dogs are usually neurologically normal.
In addition to the behavioral conditions mentioned above, neurological conditions can also cause behaviors such as whirling. Severe tail chasing has been attributed to psychomotor epilepsy and sometimes described as a seizure-related problem. There is also evidence that stereotyped behavior depends upon the dopamine systems involved in the control of movement. Dopamine turnover is increased in animals with stereotypies. This becomes important when drug treatment is to be considered. As well, there is a possibility that these behaviors may cause a release of endogenous opioids which stimulate the pleasure centers of the brain and protect the animal from perception of pain in more severe cases involving self-mutilation. In Bull Terriers, a breed that has been historically associated with dog fighting, it has been speculated that there may be a reduced pain perception, genetically passed on as an adaptation from the fighting generations. (Additional information on these neurological theories are discussed in the references cited at the end of this article).
A variety of superficial or peripheral conditions involving pain, irritation, or other sensations in the tail or hindquarters may also trigger tail chasing. Such conditions normally, however not exculsively, involve injury or disease to the skin and/or peripheral nervous system.
Certain information will be required to assess the severity of the problem and help determine whether the tail chasing is learned or medical in origin. As an owner, you should keep track of the behavior and be able to describe details to a veterinarian including: duration, frequency, intensity of the behavior, as well as the dogs history and any other known cases in closely related dogs. Treating this problem can be handled through different methods depending on the suspected cause of the problem.
If you are certain the behaviour has been learned (perhaps it was inadvertently reinforced or rewarded by laughter or attention), then the treatment would involve removing the reinforcer. In this case the reward such as attention (praise or punishment) should immediately stop and be withheld anytime the dog tail chases. Initially the dog may increase the intensity of tail chasing to gain attention or gain the reward that had previously been given. It is important not to reward the behaviour. This is a critical stage leading to the extinction of the activity. It is important that all family members understand that non-reinforcement is vital and the tail chasing must be ignored at all costs. Any kind of attention or punishment will only escalate the problem.
Counterconditioning may also be an effective treatment for anxiety by again training the dog to associate an acceptable behavior with the stimulus rather than chasing its tail. In counterconditioning you would provide a reward or give attention to the dog when it is not tail chasing.
Neurological problems are best treated with medication. Studies have shown that some stereotypies are responsive to dopamine antagonists and to opiate receptor blockers. Various neurological conditions, such as psychomotor epiliepsy, can be ruled out or confirmed by observing the response to drug treatments.
Drug therapy in combination with behavior therapies have been proven to be effective in treating stereotypies including tail chasing. A veterinarian or behavioural consultant can provide more information on drug treatment as well.
Stereotypies generally are most responsive if they are treated during an early stage of development. The best results are obtained by identifying and removing the cause of the conflict, using an appropriate drug and counterconditioning. In some extreme cases tail chasing may be impossible to prevent or cure. The best prevention is to give your dog adequate attention and exercise, a suitable environment and carefully monitor its activities.