Once a merchant had a cat and a dog. The dog had served his master well. But now that it was old, his only task was to guide the young cat. One day, the merchant decided to send his daughter a magic ring. He ordered the cat to carry the ring in his mouth and the dog to guide the cat to his daughter’s house. The cat and the dog obediently left.
On the way, they came across a river that had to be crossed. Thinking that the cat might lose the ring, the dog snatched it from him. However, while crossing the river, the dog himself dropped it midway.
When the cat told the master about the ring, the angry master sent other dogs to bite off the culprit’s tail.
Since then, whenever a dog meets another of its species it asks, “Are you the one who lost the ring?” The dog replies with a wag of its tail to prove that he is not the guilty one.
This is why dogs always wag their tails.