The movements, behavior, and ecology of the wolves in our study area
during winter are variable, and are influenced considerably by snow
conditions. This may explain the fact that in late February 1969 wolves
1051, 1053, and 1055 suddenly extended their travels and range (fig.
F-34 and table 4).
However, increased travel may have resulted from other factors. For one
thing, the wolves apparently did not need to spend so much time hunting
as before. Because of the deep snow, the ability of wolves to capture
deer increased, and the animals had a surplus of food. Perhaps under
such conditions wolves may use more of their energy for traveling than
for hunting.
[Illustration: _Figure 34.--Net weekly (straight-line) distances
traveled by three radiotagged wolves._]
In this respect it is interesting that 1051 moved right out of his area
and traveled into country that presumably was unknown to him. Wolves
1053 and 1055 each ventured into an area that was almost devoid of deer
and that even had few moose in it. Without sufficient fat reserves in
all these animals, it would seem disadvantageous for them to have made
these travels.
Evidently wolves can obtain enough food in much smaller areas than
these three animals used after February. Both 1059's pack of five and
1057 lived in relatively small areas throughout the winter and seemed
to survive well. Before late February, 1051, 1053, and 1055 did also.
Thus some factor other than food must have influenced the movements of
these three animals from late February through April.
The fact that the increased movement began during the breeding season
makes one suspect a relationship between the two. One possibility is
that the factors increasing the hormonal flow associated with breeding
in adults stimulate a hormone output in immature or subordinate
individuals that causes an increase in their movements. An alternative
is that the breeding behavior of resident packs involves the beginning
of, or an increase in, aggression toward neighboring nonmembers. This
might force the lone animals to shift about over large areas in
avoidance of such aggression.
Whatever the cause of the changes in movements of these animals, the
fact that the pack used a much smaller area than any of the lone wolves
may be of central importance in trying to understand the organization
of the wolf population. The following pieces of information are also
pertinent to such an understanding: (1) the pack, which can be presumed
to include a breeding pair (Mech 1970), chased other wolves in its
area; (2) the lone wolves, which apparently did not breed, were
tolerant of, or indifferent to, other lone wolves in their areas; (3)
the ranges of the lone wolves overlapped considerably (fig. 35); (4)
the lone wolves seemed to avoid certain large areas that one might
logically think would have been visited by them (fig. 35); and (5)
packs of wolves were sometimes observed in these large areas (fig. 35).
[Illustration: _Figure 35.--Locations of all radiotagged wolves and
unmarked packs observed during winter 1968-69, except dispersal of 1051
out of the study area. Only selected lakes shown._]
From the above information it can be hypothesized that the wolf
population consists basically of groups of breeding packs defending
territories of limited size, with lone wolves and other nonbreeding
population units that are tolerant of each other shifting about in much
larger nonexclusive areas among these territories. The information from
Isle Royale (Mech 1966a, Jordan _et al._ 1967) is consistent with
this idea, but the area of that island (210 square miles) is too small
to allow untested extrapolations to be made about spacing in much
larger wolf populations. Data from Algonquin Park, Ontario (Pimlott _et
al._ 1969) also strongly suggest this hypothesis. However, the packs
studied there could not be identified with certainty, and little
information was obtained about nonbreeding population units.
To test the proposed hypothesis with certainty, a larger number of
identifiable breeding and nonbreeding population units from the same
general area must be followed during at least one winter. This will be
the main objective of our next study.