Which body part is primarily indicative of a dog's state of happiness or fear?

The tail is a crucial body part for assessing a dog's emotional state, particularly in terms of happiness or fear. When a dog is happy, it often wags its tail vigorously and may hold it high. This behavior indicates excitement and contentment. Conversely, when a dog is fearful, the tail may tuck between its legs or be held low, showing a defensive posture. The tail serves as a significant indicator of a dog's mood and intentions, allowing observers to interpret the animal's emotional state effectively.

While other body parts such as the eyes, ears, and mouth can also convey emotions, the tail is the most overt and easily recognizable signal for happiness and fear. For example, while a dog might have wide eyes due to excitement or fear, the tail's specific movements offer clearer insight into the emotion being expressed at that moment. Understanding tail signals is fundamental for anyone interacting with dogs, as they provide essential information about the animal's comfort levels and potential reactions.