Welcome back to Science Sunday
Hard to believe there has been so little research on this crucial topic. Most of what has been written are just theories. Dog behaviourists believe that a dog’s need to perform the bedtime ritual of turning around in circles before lying down is inherited. Their wolf ancestors living in packs do this on a regular basis. The theories speculate a multi purpose of sniffing the air for predators, chasing snakes, bugs and rodents away and trampling down the grass to make a comfortable bed.
There might be a social element to circling, too. Wolves and wild dogs often travel in packs and have strict social hierarchies. When they bed for the night, they sleep in a tight circle to protect each other and stay warm. Circling might be a way of marking one's sleeping space and establishing a spot in the circle, the canine equivalent of calling first bedsies.
My favourite go to guy when researching these articles, Dr. Stanley Coren, in Psychology Today, found a similar dearth of scientific evidence for this behaviour, and so did his own study.
He was going on the theory that the circling was primarily for comfort and so devised an experiment with both a flat mat and a crumpled up shag rug. Each was placed in a 3' x 6' pen and pet dogs were brought in one at a time. The owner and experimenter sat down some distance away and waited until the dog decided to lay down and recorded their behaviour. This was done for 31 dogs in each situation.
The results were quite clear. On the smooth surface only 6 dogs (19%) circled at least once before laying down. On the uneven surface 17 (55%) circled at least once before laying down.
So it seems that comfort is at least one reason for the circling behaviour.
If the behaviour becomes excessive, it could be a symptom of obsessive-compulsive disorder in a small number of dogs.
Maybe us humans, instead of spending large amounts of money on fancy beds could just start trampling down the one we have. Try convincing your partner of this.