Since dogs are, by nature, pack animals, it stands to reason that they must be able to communicate effectively in order to prevent misunderstandings between pack members.
All dogs understand this language and they (the dogs) must get very frustrated when we can not understand them and their body language. It is essential when training your dog to try to understand the rudiments of the dogs' body language.
Your dog should regard you as the pack leader or "Alpha" and should display a submissive attitude to you and your family. A dog that will not accept this position could turn aggressive and dominant to a degree where it is likely to be uncontrollable and/or dangerous.
This does not mean that your dog should be in fear of you, just that it accepts you as the alpha and its position in the pack order.
We can learn from a dog's body language. When a dog meets another that is lower in the pack pecking order, it will display dominant language. When it meets a dog higher in the pack order it will show submissive body language. These postures are often tempered by personality. A contented dog may curl its tail over its body and/or wag it in excitement. Ears, if not the natural floppy type are held high, eyes are bright and alert and the lips are relaxed. Sometimes the tongue may loll out the side of the mouth.
A frightened dog will instinctively try to make itself look smaller and give the aggressor the sign that it is already beaten and not worth worrying about. It will also avoid eye contact and lower its head along with laying its ears back out of harms way. This is imitating puppies as most dogs normally won't attack their own young. Submissive dogs try to avoid situations by offering appeasement gestures like crouching, cowering and placing their tails between their legs. It may even lie on its back, exposing its most vulnerable part of its body. This is to let the aggressor know it is no threat. Terrified dog's eyes are wide and starring with pupils dilated whites of eyes obvious.
Dominant dogs, rather than launch an attack on another dog , which may result in injury to themselves often try to diffuse a threatening situation by showing dominant body language. They advance confidently with head and tail held high , looking straight ahead. Their hackles bristle to make them appear bigger and their ears face forward indicating they are alert and ready and not a bit concerned about any outcome. The tail held high is to expose their scent glands that tell other dogs who is the boss.
If the dominant dog doesn't receive a submissive attitude it will then snarl and wrinkle its nose to expose its teeth. It will stalk on stiffened legs ready to lunge. It will pull its ears back against its skull just before it attacks to protect them from damage in the fight.
The dog that wants to play appears similar to the submissive dog, with its head held low and back bowed inwards, front paws stretched out and bottom up, but its tail will be held high and wagging. This is known as the 'play' posture or 'bow'.
The dogs with the 'clearest' body language are those that most resemble the ancestral wolf. The more a breed has been modified by man, the more difficult these dogs will find being understood. Dogs such as Spaniels, with floppy ears can't prick or flatten their ears back against their heads. If a dogs eyes are obscured by hair, as in Old English Sheep Dogs and Pulis, with their Rastafarian-style deadlocks, other dogs can't read the intention in their eyes. Dogs with long flowing coats, like salukis can't raise their long coats and so can't raise their hackles, while dogs with naturally short or docked tails cant wag them to show they are happy, or tuck them between their legs when afraid. Black dogs may also have a problem making themselves understood, as they may appear as silhouettes to other dogs, obscuring the subtle nuances of their gestures.
Dogs may also display puppy-like behaviour towards humans, as they perceive us as superiors. In the same way that a puppy licks its mothers face to beg for food or grooming, an adult dog reaches or jumps up to lick its owner's face.