Wolves typically live in family groups called "packs." In the wild, most packs consist of two parents and their offspring, although some packs may also contain a relative, such as a sibling, of one of the breeding wolves. In exceptional cases, an unrelated wolf may be adopted into a pack. A dominance hierarchy exists within all wolf packs, and because pack hierarchy is very important to wolves, much of the body language wolves use is related to affirming it. There are four different classes of wolves within a wolf pack. These include:
(1) The alpha pair. Sometimes referred to as the breeding pair, the alpha pair consists of a male and a female wolf. These are the two wolves which will, generally, mate and produce offspring These are the two top-ranking wolves in the pack, and they are dominant over all other wolves in the pack. They often (but not always) direct the activities of the pack.
(2) Mature subordinate animals. These would include the other wolves in the pack who are subservient to the alpha pair. Often, there are two separate dominance orders within a pack - one for males and one for females, but Mech (1999) notes that is not always the case in wild wolf packs. The highest ranking wolves among the mature, subordinate animals are often referred to as beta wolves.
(3) Omega wolves. Many wolves packs contain one or a few omega wolves which may be appear to be mistreated by other pack members. Such wolves often avoid the other members of the pack and may be ambushed by other pack members should they try to approach the pack.
(4) Juveniles. These would be young wolves that have not yet secured themselves a position within the pack's hierarchy. However, young wolf pups will "play-fight" and this often results in the formation of a dominance hierarchy among the juveniles. This juvenile hierarchy often changes frequently.
The assumption is often made that some wolves are born "alphas" and that others are inherently subservient. This is not necessarily true, nor is it true that the alpha wolves are the largest, strongest or fastest wolves in the pack. In the wild, subservient wolves often disperse from their natal packs when they are about two years old, and should such a disperser find a mate and breed, it will become an "alpha" wolf over its offspring. In addition, the dominance hierarchy within a wolf pack can change if one member of the pack passes away, or another wolf joins the pack. Wolf pack hierarchy can change during the mating season, when interactions, both aggressive and friendly ones, between the animals becomes more intense than normal. Ritualistic fights become more frequent, though wolves rarely injure each other during conflicts. .
It is also not always true that an alpha wolf is the "leader" of the pack, although in many cases, an alpha wolf may direct the activities of the pack. For instance, it may lead the other wolves during a hunt, determine where the pack is to sleep and when it is to get up and it may lead a defence attack against other dangerous animals such as bears. However, any motivated wolf can do these things and pack activity can be based on the impulses of several pack members. Mech (1970) notes that there can be an element of democracy in wolf packs. The alpha wolves may appear to lead the pack in some cases, but in others, what the alpha or lead wolf does may depend on what other pack members are doing.
Wolves use a variety of facial gestures and body postures to show where they stand in the pack's hierarchy. The position of a wolf's tail can be used to tell whether or not it is a dominant wolf or a subservient wolf. During social interactions, the alpha wolves of a pack generally hold their tails up very high, and the subservient wolves keep their tails hanging down. Very low ranking wolves will hold their tails between their legs or curved alongside their legs, and subservient wolves often tuck their tails between their legs when approaching an alpha wolf to show that they acknowledge the alpha wolf's place in the pack's hierarchy. The position of a wolf's tail can also be used to tell what kind of a mood it's in. A confident wolf holds its tail up high, and a frightened wolf will hold its tail between its legs. The normal position for a wolf's tail is down, and wolves typically hold their tails this way when relaxed.
The position of a wolf's ears can also be used to tell where it stands in the pack's hierarchy or how it is feeling. Alpha wolves always keep their ears erect, while lower ranking wolves often keep them flattened, particularly when they approach an alpha wolf. A wolf who is feeling cautious or apologetic will hold its ears back against its head, and a happy, confident or playful wolf will hold its ears high and erect. A wolf that wants to threaten another will hold its ears forward. Also, dominant wolves (regardless of sex) urinate with the raised leg position and subservient wolves squat down to urinate .All of the guard hairs on a wolf's body will stand on end if it is trying to threaten another wolf, and it will also raise its upper lip to bear its teeth..
Wolves also have many more specific ways to show where they stand in their pack's hierarchy. A low ranking wolf will often greet an alpha wolf by keeping its body low to the ground, with its fur and ears flat. It will then reach up and gently lick or nip the muzzle of the alpha wolf. This behaviour is very similar to the food-begging behaviour often displayed by young pups. Sometimes, all pack members will greet an alpha male in this manner when he returns from being absent . This behaviour is called active submission.
If a subservient wolf tries to resist the authority of an alpha wolf, the alpha will try to get the subservient wolf to submit. Sometimes, the alpha will only need to give a stern stare to the rebellious wolf. The dominant wolf may have to growl and bear its teeth at the rebellious wolf or it may crouch on the ground as if it were going to pounce on the offender. A dominant wolf may also hold the muzzle of a subordinate wolf to assert its authority A dominant animal may also place its front paws across the shoulders of a subordinate animal or try to stand over it to assert its authority. When the subordinate wolf is ready to submit, it will lie on the ground and expose its side and belly to the alpha wolf. The wolf may also urinate. This act is called passive submission, and the alpha wolf will accept it as though it were an apology.
So, in general, much of a wolf's behaviour is directed towards asserting its own status or showing that it accepts the higher status of another wolf, though wolves certainly don't go around constantly trying to reaffirm their place in the dominance hierarchy. This helps keep pack activities relatively stable and prevents fighting within the pack. However, fights may occur between contenders for the alpha position if an alpha wolf dies. Aggressive encounters between females often occur during the mating season, as the alpha female of a wolf pack often becomes quite aggressive towards subordinate females during this time. She will physically assault any females who attempt to copulate with a male. Dominant males will also disrupt any subordinate males who attempt to mate with a female. Serious injuries, however, are quite rare.
Wolves within a pack may also behave aggressively towards a low-ranking omega wolf. Dominant wolves will often pounce on and ambush such a low-ranking wolf if it approaches the pack too closely. In addition, minor disagreements often occur while a pack is feeding on a carcass. It is not true that dominant wolves can take food from a subservient pack member. In wild (Mech, 1999) and captive (Mech, 1970) situations, subservient wolves with protect pieces of food in their possession from being taken by dominant wolves.
Interestingly, it has been noted that dominance contests in wild packs are less common than dominance contests in captive packs (Mech,1999). Most studies on wolf behaviour involve captive packs, since wild wolves are rare and difficult to observe. However, Arctic wolves (Canis lupus arctos) are somewhat easier for researchers to observe than other wolves, since they are not as shy around humans because they have not been hunted and persecuted as extensively by humans as wolves at lower latitudes have. During thirteen summers of observing wild Arctic wolf packs, Mech (1999) did not observe any major dominance contests within the packs. It was noted that most wolves within packs dispersed from their natal packs before they reached sexual maturity at age two, so pack hierarchy was always stable , with no fights over breeding privileges occurring. Young wolves were always subservient towards dominant wolves (typically their parents), with displays of active and passive aggression being observed. The breeding ("alpha") female wolves always approached breeding male ("alpha") wolves in a subservient manner, with one exception where a male wolf approached his mate at her den when pups were present (Mech, 1999).