What does this dog body language mean?

a - aggressive or fearful or both

b - submissive and compliant

A: angry, giving fair warning that he is pissed and will bite.

B: scared and will bite out of defense

What to do if you're in a situation with a dog like A:

If you're walking down the street and see a dog doing A, DO NOT MAKE EYE CONTACT. That only "challenges" the dog to go at you and fight with you. If you notice at how dogs start fighting, they're both looking into each others eyes. The one who looks away is submissive, but if they both continue to stare, it's pretty much a stare down and they fight to determine who is alpha to the point of death. When you see a dog doing this, look away and try to back away slowly without any sudden or fast motions. It does not matter if the dogs tail is wagging (as some people who don't know the dog psych thinks it DOES matter). Just try to get away from that dog, and if anything, call animal control to have the dog picked up so that it is not a danger to other people, other animals, and itself.

If you a see a dog doing B, it is most likely scared. Dogs who usually do that type of teeth baring USUALLY also have their ears back, and back side slightly tucked under and their tails are wagging low and fast. This means they are scared sh*tless and will bite you if you try to touch it. If you encounter a dog like this in the middle of the street, you pretty much don't have to worry about it chasing you down to attack. It is scared and will bite out of defense. It can also be that the dog is nervous, and therefore scared. In either case, don't approach the dog unless you are trained to know how to handle animals in that state. And you should still call your local animal control to keep it safe. Dogs in panic will do anything if it feels threatened. Hope this helps. If you need anymore information you can try contacting at actual trainer or the Human Society for information.

A) Dogs that are openly aggressive behave in a manner as described in part "A". When the whole of the mouth is exposed, its a warning gesture that a bite is extremely possible if not completely inevitable.

B) The description B makes me think directly of a dog thats not going to lash out, but is sub missing to the point that its vulnerability makes it frightened.

Either way, both cases need to be regarded delicately and gingerly to prevent psychological damage to the dog, or physical damage to the handler.

Example A is a dog that is displaying aggression or a warning

B is a submissive gesture.

A. aggressive or fearful

B. Not sure...never seen that behavior nor have I heard it described before.

you mean like this

http://www.vetnetwork.net/pca/articles/news/images...