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Flank Sucking



Submitted courtesy of Gail Vetorino

A few months ago, a request for information about flank sucking came to me from the Public Education Committee.  Because the request was from a dog trainer, the response I sent (below) is a definition of the behavior coupled with diagnostic and treatment information.  Lick granuloma (acral lick dermatitis), foot
licking/chewing, licking and sucking objects and self scratching also fall into the same category of grooming stereotypes.

Whether using traditional, natural and/or holistic treatment methods, analysis of the lifestyle and environment of the dog with should be given top priority as the key to understanding why the dog has developed ritualized coping behaviors.  Modification with medication should be done in conjunction with environmental analysis and behavioral consultation with a veterinary behaviorist.

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Flank sucking behavior in dogs is almost exclusive to Dobermans.  It is part of a category of sucking and licking behaviors that are known as grooming stereotypes.  Stereotypes are highly repetitive, ritualized, with-function or functionless acts that animals perform periodically or continually. Stereotypes can differ in degree of expression from periodic and seemingly benign, occupying time and providing self-reward to the animal and going to the extreme of uncontrollable obsessive-compulsive expression with self-mutilation and interfering with the normal function of the animal.

Studies involving farm and zoo animals have lent insight into stereotypes as they relate to companion animal behavior.  From these studies, inappropriate animal management involving problem environments can be a factor in the development and perpetuation of animal stereotypes. There is also evidence that hereditary effects, as seems to be the case with Dobermans as the sole breed expressing flank sucking, may influence types of stereotypical behavioral disorders.  Human clinical psychology and psychiatry have also demonstrated similarities in animal stereotypes to human obsessive-compulsive disorders.  The effects of some canine stereotypes on brain chemistry and function due to sensory input from repetitive activities can be an important factor in some cases.  Unintentional human reinforcement of the behavior can also be a factor in the development and perpetuation of stereotypes.

From examination for the presence of the possible factors influencing and/or reinforcing the stereotype, a behavioral modification treatment plan can be devised.  Considerations should include; are exercise and training needs being met; is there a structured lifestyle for the dog; is there unintentional reinforcement by the owner; is the behavior associated with attention seeking; is it an expression of separation anxiety (is the Doberman you mentioned as demonstrating anxiety-linked thigh sucking suffering also from separation anxiety?); can the animal be distracted from the behavior; is the behavior constant or intermittent; what is the duration of the behavior (just started or very habitual); is there a lack of mental stimulation in the environment (in essence, lack of opportunity to exercise dog activities – no outlet for drives); is the environment highly disturbing, stressful or threatening (causing anxiety); is the dog in some way frustrated by the owner or circumstance of its life (being tied, unjustly punished, constantly crated)?  Identifying and correcting or eliminating casual factors in the dog’s environment provides insight into the motivation of the behavior and identifies modes of behavioral modification as is possible. In many cases, even after casual factors are identified and corrected and modification techniques applied, the stereotype behavior is not substantially changed.  At this point, medication along with behavioral modification can help the animal.

From the considerations above and given the genetic tendency of Dobermans to engage in the stereotypes of sucking behaviors, the dogs that express this behavior are probably genetically disposed to do so as a trait of their temperament.  That in some dogs it remains a mild coping relaxation behavior and in others it becomes obsessive and chronic could be because of both genetic and environmental influences.  At this point, it is important to distinguish in which dogs the behavior becomes disabling and mutilating, and in which dogs it is merely a pleasant pastime.  Many Dobermans can engage in flank sucking without it ever becoming destructive and overwhelming in the dog’s life.  Some don’t suck on their flanks, but on other objects such as comforters, stuffed animals and soft blankets.  They are not destructive, can be distracted out of the behavior and are normal and healthy dogs with good owners and functional lifestyles.  However, the behavior is still stereotyped, habitual and most likely provides relaxation by releasing endorphins.  At this level, whether to tolerate or change the behavior can be at the owner’s discretion.

However, the dog that cannot be distracted from the behavior and only stops because of physical restraint or exhaustion, is licking or sucking so much that sores and infections are appearing and is destructive is in another category entirely.  Treatment is necessary so that the dog does not mutilate and destroy itself.  Part of the issue is owner understanding of the behavior.  With mild expression of the behavior, it is possible to designate when and where the dog is allowed to practice it.  It is possible for the owner to still control the behavior.  In some instances when the dog sucks an object and not itself, allowing the behavior can be used as a “relaxation reward” for the dog, just as chewing a bone can provide relaxation for the dog.  In severe expressions, this is not possible, and the more the dog is denied the opportunity to practice the flank sucking, the more likely it is that he will become increasingly anxious and motivated to return to the stereotyped behavior.  Denial of the behavior does not solve the problem. It is very important to eliminate environmental influences on the behavior and recognize genetic tendencies.  Typically, with these dogs, topical treatments such as bitter apple and bandages or Elizabethan collars do not provide cures, but only temporary solutions. With the dog that is progressively expressing stereotypes of increasing duration and intensity and is not responsive to environmental changes and behavior modification efforts, it is important to seek the help of a veterinary behaviorist.  They can correctly diagnose and provide behavioral modification recommendations along with a drug therapy protocol.

Stereotypes are fascinating dog behaviors, and especially as they relate to human behavior studies and modification.  Many of the drugs used for humans and dogs are the same, and while not specifically approved for canines, these drugs have been found to be effective.  If behavior modification with or without drug intervention is successful, it is important to still recognize the stereotype as a life-long affliction of the dog.  Although cessation of the behavior can occur, any time the animal is placed into an environment similar to the one in which the stereotype was previously practiced, is in a situation conducive to the stereotype, or the animal is sufficiently stressed, they may revert back to the stereotype behavior.