Social Spacing

Den location

Ciucci and Mech (1992) argue that there has not been enough attention devoted to studying the wolf den position within the territory. Most den research involves the structure and characteristics but neglects the position. These authors contend that there are large-scale factors that potentially play a role in determining the den site. Such factors include, but are not limited to, the wolves' knowledge of the territory, the size of the pack and the territory, the configuration of hunting areas and the distance to the surrounding packs.

Dens tend to be located somewhat randomly toward the center within a 60% mean radius (Ciucci & Mech, 1992). Further, 21% of the dens in this study were located in the outer portion of the territories. One important point to note is that there is a tendency for territory size and den location to be related, with the larger territories having more central dens. Ciucci and Mech (1992) assert that this result likely indicates that the wolves are trying to minimize their travel distances to and from the den.

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Indeed others have found that den sites are usually located near the center of pack areas, which is somewhat different from territories (Ballard et al., 1987). It is the area that is frequently occupied and utilized. Den sites were usually abandoned in July in favor of one or two rendezvous sites for the rest of summer through August. Other evidence in support of minimizing travel distance has been found: the need to acquire a den near a food source appears to be more important than having a den located near the territory's center, again minimizing travel. It was determined that only two of nineteen dens were located within a 1 kilometer strip of the territory's boundary. This is likely observed because there is an attempt to reduce the inter-pack contact and conflict. Furthermore, one of the two dens was situated next to a large lake, where inter-pack contact would not occur anyways.

Wolf movements and territory use

Wolves move around within their territory in order to search for prey, to mark territories, to join members at the den or rendezvous site, and go on hunts (Jedrzejewski et al., 2001). There is a strong relationship between wolf dynamic movements and the predation techniques that they will employ. Territory use is thus tailored to suit the movements of their prey. The area that the packs travel can be compared with the pack sizes, and the density of their ungulate prey. It has been determined (Ballard, 1987) that wolves do not follow the movements of moose or caribou outside of their main pack areas, but the pack is usually willing to follow elevational changes of moose within their areas. Occasionally, individuals of a certain wolf pack were temporarily observed to associate with other packs. The result was usually that the wolf would disperse from the old pack, or be killed by the new pack. A majority of these lone wolves were dispersers who were trying, unsuccessfully, to locate an empty habitat and find a mate.

There is also a seasonal variation in wolf travel (Jedrzejewski et al., 2001). Daily movement distances (DMDs) were calculated for wolves in an attempt to see any gender or seasonal differences. It was noted that monthly mean DMDs for all wolves were 26.2-26.6 km in January through March compared to 15 km in May, when the pups were young and stayed in the den. The movement throughout the summer concentrated on the den and the rendezvous sites, while in winter, the larger values are observed because the wolves utilize the territory in a rotational way. They would return to the same parts every 6 days. This rotational use is related to patrolling and defense of the territory and can also help with their prey availability, ensuring that they have food to eat (Jedrzejewski et al., 2001). There were also differences in wolf travel based on sex and age of the wolves. Large DMDs were observed for alpha males in February because it was mating season. Furthermore, the adult alpha females reduced their travel in May, when they were giving birth and caring for young. Overall, males had larger DMDs than females. The wolves' hunting activity also affected the length and speed of their movements. As was predicted, the wolves moved much more before a kill than after. On any certain day, a wolf will only cover 21.4 square km of their area, which is roughly 9% of the pack's total territory area.

Buffer zones

It has been mathematically demonstrated how the reduced predation by wolves in these buffer zones allows their prey species to find a refuge (Lewis & Murray, 1993). Buffer zones are usually more heavily scented than other areas of the territory as they occur in places where wolves are more likely to run into a dangerous situation. These buffer zones are rarely hunted by wolves until they become desperate, because there is a higher risk of a fatal encounter with neighboring wolves (Mech, 1977). Wolf scent marks advertise information about the territory to other packs about how long ago and how frequently they have visited that area.

Of the marking methods, raised leg urination (RLU) is the primary mechanism, and thus, the one that is most frequently studied. RLU marking could as much as double near the territorial borders. Wolf movements and deer movements have been tracked and correlated with the levels of scent marking (Lewis & Murray, 1993). Wolf pack/RLU density functions were plotted to demonstrate that wolf territories are stationary and stable. Deer locations were primarily found to occur where the combined wolf densities were the lowest, in the buffer zones. Thus, the scent can be recognized not only by the neighboring packs of wolves, but by the prey, who use it to their advantage. With this evidence, it demonstrates one potential drawback of the scenting behavior--that the wolves may lose some opportunities to kill ungulates.

Interestingly, in a white-tailed deer herd that was declining, those members of the herd who survived were the ones who were distributed along the edges of wolf territories (Mech, 1977). Deer usually are evenly distributed throughout wolf territories when their herd does not become "endangered." In this study, a high wolf population led to the deer becoming killed more frequently. Consequently, the wolf pups then began to starve more frequently as the prey became depleted; further the adult and adolescent wolves became less productive. Only then would the packs trespass into other territories and buffer zones in search of food. The remaining deer populations would attempt to hide in the buffer zones and reproduce.

As the deer numbers began to grow, the maturing individuals would disperse and expand their home range to a much larger space than that in which they were born. In this way, prey maintain a mechanism of surviving--by retreating to the buffer zones when they are outnumbered and outmatched. They will then mate in an attempt to produce mature and viable offspring that can repopulate the wolf territories.

Territory or Home range?

There are clues about wolf movement that suggest that they may be home range or territorial. They are able to migrate hundreds of kilometers while following prey during the winter, yet they also raise their young in dens. Their mobile food source would suggest that they need to have home ranges to find enough food to feed a pack of hungry wolves. However, they also mark their territory and do not typically associate with other packs as demonstrated by the presence of buffer zones (Mech, 1994; Smith, 2002; Jedrzejewski et al., 2001). It has been noted that gray wolves will use their territory in different ways at different parts of the year, making preparations for and rearing their pups during the spring and summer seasons while following their prey more frequently during the autumn and winter months (Jedrzejewski et al., 2001).

This dichotomy suggests that they are partially home range and territorial, although it is firmly noted that they defend territories at all times of the year (Mech, 1994; Mech 2003). I would suggest that the wolf behavior closely resembles that of a classical territory in the summer while it is more like a home range in the winter because the pack is more mobile, does not have a pronounced home (only a rendezvous site where hunts are coordinated and activities take place), and they will be more likely to cross into buffer zones as ungulate availability becomes more scarce.