Smithsonian.com

Photo: timekin

Isn’t it adorable when Fluffy chases her tail like a deranged nut on the living room carpet? The answer is yes, but as adorable as it is, it’s also kind of sad. But dogs engaged in this futile repetitive behavior probably don’t have much of a choice. New research in the journal PLoS One links dog tail-chasing with some of the same genetic and environmental factors that drive human obsessive compulsive disorders.

To investigate this universal pet occurrence, the study authors began by asking what causes some dogs to obsessively tail chase while others can sit for hours, composed and docile. They gave nearly 400 Finnish dog owners a questionnaire that asked about stereotypic behaviors noticed in their pet, aspects of their dog’s puppyhood and Fido’s daily routines. They took blood samples of each dog and evaluated the pooch’s personalities based on the answers the owners provided.

They found a few similarities between the tail-chasers that, uncannily enough, also somewhat corresponded with symptoms of many human sufferers of OCD. These traits included an early onset of recurrent compulsive behaviors and an increased risk for developing things like compulsions, acting timidly, a fear of loud noises, sometimes compulsively freezing. Also like humans, dog compulsions can manifest in different ways or in a combination of behaviors. Some dogs engage in repetitive behaviors like chasing lights or shadows, for example, or biting and licking their body repeatedly.

Most of the dogs, the authors found, started chasing their tails between the age of 3 to 6 months, or before reaching sexual maturity. The severity of the symptoms varied; some dogs chased their tail for several hours on a daily basis, while others only partook a few times a month.

The researchers discovered that the dogs that never chased their tails or those that chased their tails less tended to receive extra vitamin and mineral supplements in their food.  Though they haven’t established a direct cause-effect link, the researchers plan to follow up on this initial finding to more deeply explore the relationship between nutrition and tail chasing.

Early separation from the mother also tended to predispose dogs to tail chasing, as did mother dogs who took poor care of their puppies.

Surprisingly, the amount of exercise didn’t seem to have anything to do with how often dogs chased their own tails, the researchers found, which might come as comforting news to some owners who blame too few walks or not enough play time on their dog’s behavior.

Anecdotal links between some of these traits and certain dog breeds suggests that genetics may also play a role alongside environmental factors. German Shepherds and Bull Terriers, for example, most commonly chase their own tails. The researchers next aim to pinpoint the gene regions connected to tail chasing.

Thanks to the seemingly apparent relationship between genes and environment that creates the perfect storm for an onslaught of compulsive tail chasing, the researchers think that dogs might serve as good animal models for studying the genetic background of OCD in humans.

“Stereotypic behavior occurs in dogs spontaneously; they share the same environment with humans, and as large animals are physiologically close to humans. Furthermore, their strict breed structure aids the identification of genes,” the researchers point out in a press release.

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A Mellow Dog in the Grass