Here are some basics you need to know about dog culture:
The most important concept to grasp, is that dogs do not understand, care about, nor can you teach them the concept of fairness. It's lacking in their social system.
By this, I am referring mostly to equality, sharing, taking turns, and all the other good things we learn in kindergarten.
You see, dogs, just like their wild cousins, are born understanding how hierarchical social structures work. In a hierarchy there are no equals. Two dogs must determine how they relate to one another in order to interact normally. Who is higher ranking? Who is calling the shots in a relationship between two dogs?
To keep it simple, dogs need to know this so they can determine mostly two main things:
Who has the right to initiate?
Who has the right to unclaimed resources?
These are the rights of the higher ranking dog and are meant to prevent unnecessary fights.
Initiate – who initiates and sets the rules for play, grooming, and most other activities.
Unclaimed resources - who has the right to something desirable that no one yet possesses.
Besides the interactions between individual dogs that are all unique in how they relate to each other, you will sometimes have an "alpha" in a group of dogs. The alpha (highest ranking of the group) also initiates group activities such as roaming, hunting, and initiating aggression/acceptance toward outsiders. Regardless of how the other dogs in the "pack" relate to each other (dog "A" may lead "B", dog "B" may lead "C", and dog "C" may lead "A"), you can say there is a true alpha in the pack when all the dogs follow the lead of that one. So depending on the wild or especially domesticated situation there may or may not be a true "Alpha".
Generally, higher ranking dogs cannot be pushed into engaging in activities he/she is not ready to do. Any pushy behavior from others is either ignored or diffused by absolute minimal amount of threats that rarely escalate to aggression (which almost never result in injury). In fact, most alphas and other higher ranking dogs will keep peace in the lower ranking pack by splitting up (mostly with their body) and diffusing aggression between dogs. Much of their culture can be explained by these rituals of control mainly through the stronger willed and confident personality types and less by the last resort of aggression.
Bear in mind that certain behaviors override hierarchical rules. These are classified as SURVIVAL INSTINCT behaviors.
Survival instinct behaviors are all fear based and are dealt with differently in dog training than issues that are explainable through hierarchy (pack structure) issues.
For instance, a dog will generally not show aggression to a higher ranking dog or human when the higher ranking one initiates contact. But, if that dog is in pain (or anticipates pain) the dog may show aggression because his instinct to avoid that pain may override the rules of subordination. Also, a dog may disobey a command from the owner or not follow his pack leader if he is fearful of where that action may bring him.
Another interesting and often misunderstood behavior that is placed into this category is food aggression. This behavior is sometimes referred to as a dominance (pack structure) issue. From many years of observations this is only true if the dog shows aggression toward UNCLAIMED food (a resource). If there is a steak in the middle of three dogs the highest ranking one is likely to show aggression only if one of the others goes to claim that steak while he is on his way to also claim it.
But, if the lowest ranking of those three dogs happened to already have that steak and the two higher ranking discover him with it, the rules may change. If the lowest ranking dog shows aggression as the other two approach, it is not considered a challenge to the hierarchical order by the two higher ranking dogs. It is actually a form of survival instinct which is a throwback to the dog's wild ancestors. In a pack of wild canines, if the lowest ranking individual always had everything taken from him, he would starve to death. So, when food is unclaimed it goes to the higher ranking - but claimed food usually stays with whoever has it. In fact, a higher ranking dog will often guard a lower ranking dog who is eating from other challengers, but that higher ranking dog will also be able to take what the lower dog leaves behind without challenge from other pack members because it is once again an "unclaimed resource".
This an ancient set of rules that helps prevent unnecessary fights and rewards good pack leaders with a large and healthy pack. Poor pack leaders often cause unnecessary injury to themselves and others. Since puppies are born into submissive (follower) roles, it very uncommon to witness major conflict or fights in canine family units that have these well balanced instincts. Pack structures remain stable often for years.
Chaos is more likely to be observed when initially combining new canines into a "forced pack" of shared resources, and in situations where there is a dog or dogs that have lower instincts to adhere to these rituals and do not use minimal amount of aggression during conflict. Also, certain domesticated dogs that have low resource guarding instincts may find all of their "resources" stolen from literally right under their nose if there is not a good "alpha", dog or person (hint hint) to keep the "pack" in check.
Some domestic dogs, more than others, will display the primitive instinct of food (and other resource) guarding. It is an instinct that was historically discouraged through selective breeding of our domesticated versions of wolves, particularly in the sporting breeds which were needed to easily retrieve and hand over dead game to their masters. But now, "resource guarding" is much more prevalent, even in the sporting breeds, because the pet industry has largely ignored selective breeding for functional purposes. Therefore, a dog that does well in the show ring or is a good producer at a money motivated puppy mill, may be used for breeding, and passing along certain genetics, regardless of behavior traits.
A simple understanding of the roles a dog has as a "leader" and "follower" in a relationship is the least you need to know about their culture to move forward.
Next you need to be able to read some of your dog's basic body language to understand what he is trying to communicate.