https://wigglekingdom.com/a/blog/do-dogs-wag-their-tails-when-they-are-happyVisit Wiggle Kingdom and get the reason why do dog wag their tails is because dogs use their tails to communicate with other dogs.For example, when a dog sees another dog he's friendly with,he may wag his tail more slowly to show he's not a threat.https://audiomack.com/wigglekingdom/song/wants-to-buy-e-collar-for-pup