Zooillogix

Everybody thinks a wagging tail is the sign of a happy dog. But researchers have recently made a telling discovery: a) not all tail wagging is necessarily positive and b) one can tell this by which side (left or right) the tail wags on!

Happy dog, Carnivorous Slobbius

According to a new study--,AeuAsymmetric Tail-wagging Responses by Dogs to Different Emotive Stimuli,,Aeu by Giorgio Vallortigara of the University of Trieste in Italy and Angelo Quaranta and Marcello Siniscalchi of the University of Bari, Italy--positive feelings are displayed by wagging on the right side, while more negative feelings are wagged on the left.

Italians are known for their love of slow-cooked meals, opera, fine art, dog hindquarter geometry.

Studying 30 family pets of mixed breeds, Dr. Vallortigara tracked the angles of the dogs' tail wags with cameras as the dogs were shown four stimuli: their owner, an unknown human, a cat, and an unknown, aggressive dog.

With startling uniformity, the dogs tails wagged to the right when they saw their owners, and then less and less so as the stimuli progressed, ending with definitive left-sided wagging for the angry, unfamiliar dog.

Which side is my tail wagging on right now? Why don't you come over here and check?

Scientists speculate that the dogs' tails reflect the natural asymmetry of their brains: the left side (which controls the right side of the body) is associated more with positive feelings and the right side with fleeing and depression.

Researchers have yet to determine which side of a dog's brain controls sprinting around in circles uncontrollably and then rolling around in filth after taking a bath.