No one watching.
Does a dog still wag?

The full narration of the video.

With no one watching, a dog wags a lot less. Open the front door, and its tail won't stop. But eating alone, head in the bowl, its tail often stays still.

So why do dogs love to wag? And who is it for? Scientists ran a small experiment to find out. A bowl of treats sits in front of a dog, just out of reach, and then it's taken away.

Every dog gets frustrated. Only one thing changes: sometimes a person stands nearby, sometimes the dog is alone. The result was clear: with a person there, dogs wagged far more.

They also measured the dogs' stress hormone. The big waggers weren't more stressed. If wagging just showed frustration, an audience shouldn't matter.

So how much a dog wags doesn't track how upset it is. It tracks whether someone is there. It's like raising your hand in class. You raise it for the teacher. Doing homework alone, nobody raises a hand at the wall.

A wagging tail is a dog talking to whoever is around. Newborn puppies just eat and sleep. Their tails can move, but they barely wag. Around one month old, they start playing with their littermates, and the wagging begins.

Once there's someone to talk to, the tail has something to say. Scientists call this the audience effect: behaving differently when someone is watching. You're the teacher. The wag is its raised hand.

But that hand doesn't always mean happy. A low, gentle wag usually says: I mean no harm. A tail held high, flicking fast and stiff, may say: I'm tense. Back off.

A big, loose swing that wiggles the whole rear end is the one that says: so glad to see you. Every dog carries its tail differently, so these are rough guides. Check the ears and body too. People do it too. After a strike, many bowlers don't smile at the pins. They smile when they turn and see their friends.

The time your dog wagged hardest, what were you doing?