Many bites can be prevented if people learn to read a dog's body language.
This dog's whole body is wagging calmly and he is panting. He is happy to see You.
He is not yawning because he is tired. He is anxious and he hopes you will leave him alone.
Her tail is high, her body is stiff and her mouth is closed. "I'm warning you. Back off!"
A tail tucked in, even if wagging a bit, means a very worried dog. "Please stay away from me."