Communication with your dog can be rewarding -- or quite frustrating if you don't know what he's saying. Dogs are able to use their eyes, mouths, ears, tails, posture -- even their individual hairs -- to communicate with other animals and, with a little practice, humans as well. Body language is by far the most complete form of communication; however, dogs can understand and use a variety of vocal and other sensory cues as well.
Expressive Eyes and Ears
An aggressive or threatening dog will maintain wide-eyed contact with his opponent, whereas a happy pup at ease will have relaxed, normal-sized eyes. On the other end of the spectrum, stress or fear may appear as a cringing expression -- small, squinting eyes and the laying back of the ears. Direction is equally important, and others should steer clear of a dog that seems to be peering from the corners of his eyes. Watchful and alert eyes accompanied by either natural or perky ear placement suggest friendly curiosity toward his surroundings.
Lips, jaw and teeth can send a message without making a sound. A slack jaw, slightly open or closed generally represents contentment. An active, panting dog may show an open mouth, perhaps with a tongue hanging out to keep cool. But, if lips are raised and teeth bared, this dog clearly feels frightened or threatened and is preparing to hold his ground. This response to a threat can escalate to the vocalization of growling or may turn into a yawn or lip-licking should the pup decide he's going to let this one go and submit.
Tails and Hair
When it comes to the tail, position is as important as the wag itself. A tail held in a natural position communicates a calm, peaceful attitude; a wag may be present if he's feeling especially happy or friendly. However, a wagging raised tail projects dominance, especially one that seems to wag rigidly and tells his audience he intends to stand his ground. It's important to remember some dog breeds have docked tails, such as rottweilers, or naturally curly tails, like pugs, and thus, communication can get mixed up by anatomy. Excessive shedding means your pup is scared, while "raising the hackles," or hairs along the spine, displays uncertainty, aggression or insecurity.
Posture speaks volumes about how a dog is feeling and is one of the easier forms of communication to understand. Submissive and timid dogs will attempt to look as small as possible, whereas a pup who sees a challenge ahead will stand tall, muscles tense.
Communication methods are not mutually exclusive in any species. Body language is huge, but it may be accompanied with vocalizations like barking to alert others of danger, to let his human know he's hungry or that he needs a pit stop, or simply that he's lonely. Whimpering or crying often signifies pain or anguish, whereas chemical communication such urine marking can let others know not to mess with his space. Dogs, each having their own unique personalities, may use one or all of these methods.