Caudal Communication in the Canids

A research team from the Department of Biology at the University of Victoria, Canada, have, for the first time, investigated the  behavioural responses of domestic dogs (Canis familiaris) to the asymmetric tail-wag of a life-sized robotic-dog model – one which was configured to wag its tail, either to the right or to the left, at around 2.5Hz.
The new experiment compliments and extends earlier studies which have consistently demonstrated that dogs wag their tails asymmetrically depending on their motivational state.(Example here). They tend to wag to the left when faced with an unfamiliar dog or neutral stimulus, and to the right for heterospecific stimuli (an owner, an unfamiliar human, or a cat) – perhaps this laterality-bias might provide informational cues to an approaching dog?

“We consider whether such asymmetry in motion of the tail, a crucial appendage in intra-specific communication in all canids, provides visual information to a conspecific leading to differential behaviour.”

The results were clearcut.

“Our data, involving 452 separate interactions, showed a significantly greater proportion of dogs approaching the model continuously without stopping when the tail wagged to the left, compared with a right wag, which was more likely to yield stops.”

See: ‘Behavioural responses of dogs to asymmetrical tail wagging of a robotic dog replica‘, published in the latest issue of the journal Laterality.

Note: The photo above is taken from a previous research project conducted at the same department. For this latest experiment, the robo-dog was modified by the addition of Parallax Stamp® Microcontroller circuit board and a 3 cm long white sock over the end of its tail.