[Cowperson]

What is your dog telling you when it wags its tail to the left or to the right?

Scientists have made it their mission to find out.

Why does your dog Dog tails are interesting, Dr. Davidson said, because they are in the midline of the dog’s body, neither left nor right. So do they show emotional asymmetry, or not?

To find out, Dr. Vallortigara and his colleagues recruited 30 family pets of mixed breed that were enrolled in an agility training program. The dogs were placed in a cage equipped with cameras that precisely tracked the angles of their tail wags. Then they were shown four stimuli through a slat in the front of the cage: their owner; an unfamiliar human; a cat; and an unfamiliar, dominant dog.

In each instance the test dog saw a person or animal for one minute, rested for 90 seconds and saw another view. Testing lasted 25 days with 10 sessions per day.

When the dogs saw their owners, their tails all wagged vigorously with a bias to the right side of their bodies, Dr. Vallortigara said. Their tails wagged moderately, again more to the right, when faced with an unfamiliar human. Looking at the cat, a four-year-old male whose owners volunteered him for the experiment, the dogs’ tails again wagged more to the right but in a lower amplitude.

When the dogs looked at an aggressive, unfamiliar dog — a large Belgian shepherd Malinois — their tails all wagged with a bias to the left side of their bodies.

http://www.nytimes.com/2007/04/24/sc...903&ei=5087%0A

Cowperson