Today I was reading a curious publication ‘Home range formation in wolves due to scent marking’ by Briscoe, B.K. et al. (2002).
In the study, mathematical modelling was applied in order to determine whether scent-marking and reacting to their own scent-marks (spending more time in the vicinity of existing scent-marks left by the respective individuals and moving of farther and at a greater rate where the density of scent-marks left by the respective individuals is lower) might by itself produce ‘a wolf range’ (establish use of land that conforms with the known properties of a wolf territory).
The study referred to common assumptions that territory (in this case, home range) is formed with respect of den site location and/or with respect to scent-marks left by other wolves (other packs).
In this publication, the mathematical modelling did not include den site, nor ‘foreign scent-marks’ (although these might undeniably be important factors for wolves in real-life situations) because sometimes home ranges (restricted use of land) are formed in absence of neighbours and without den sites (e.g., prior to reproductive activity).
I found it curious that wolves appear to form a home range solely in response to their own scent-marks.
I believe that it also suggests that the beginning of a wolf’s home might lie with pairing up or grouping up with a mate / other lone individuals because a home might, under the conditions of this model, become formed when scent-marking rate is increased and when it is possible to remark existing marks.
A lone dispersing wolf is known to cover large ranges and to try leading an inconspicuous life while crossing other wolves’ territories.
This might indicate that lone wolves cannot scent-mark as often and they cannot revisit their own scent-marks, either (because they should avoid drawing attention to themselves and they cannot linger for a long time on other wolves’ territories), unless they have come across a patch of land which has not been occupied by other wolves.
Thereby, the reason for establishing a home outside of other wolves’ ranges might involve avoidance of scent-marking while on other wolves’ territory and ‘freedom’ to scent-mark more often as well as to return to locations outside of occupied range.
However, not all unoccupied land is turned into a wolf’s home.
This might mean that it is necessary to involve several wolves (to increase scent-marking rate and/or density) and it might also mean that homes are founded in places with resources worth marking (often food is scent-marked and thereby the presence of prey might at the same time indicate that the habitat is optimal but also it might initiate more frequent scent-marking and the respective response by the scent-marking individual to their own scent-marks, i.e., staying longer someplace because it carries one’s own scent due to having foraged there more than once).
Scent-marking might also be induced at greater rates in response to scent-marks by other wolves.
If the individual feels safe enough to respond to scent-marks by other wolves, they would probably scent-mark both food resources and ‘foreign scent-marks’ which would lead to a higher ‘home-making response’ in the vicinity of other wolves’ territories (wolves would be likelier to settle down closer to other wolves even in situations where a mate has already been secured).
Additionally, scent-marking rate would be increased, for example, if the individual encountered a potential mate.
The reason why wolves settle less often in no-wolf land might not be solely related to lack of mates or unsuitability of the habitat but rather to lack of scent-marking activity (no reason to scent-mark often) which might halt forming attachments to this patch.
Collective scent-marking is a sign of wolf courtship and this could lead to higher scent-marking rates (as well as to becoming drawn to their own scent-marks) and to trying to find a patch of land where this could be achieved more or less safely.
Perhaps sometimes wolves take over other packs’ territories (or parts of territories) because they meet one another in a location which is not ‘freely available’.
There might some type of a threshold of scent-marking activity above which the individual is unwilling to leave.
If this threshold (e.g., due to courtship activity) happens to have been surpassed on other pack’s territory, the new arrivals might attempt to appropriate the portion which has been scent-marked by them.
If reaction to one’s own scent-marks is at all important in determining where an individual finally finds their home, scent-marking activity between lone wolves, pairs, dispersing groups of wolves and actual packs should be compared in order to understand how it affects reaction rates to one’s one scent-marks and how these reactions become attached to certain localities and distribution of marking sites.
For example, wolves are known to scent-mark roads rather often on their own territories.
Meanwhile, wolves try to establish homes farther from roads on a landscape scale.
This might suggest that only packs scent-mark roads (when already in their home) while lone wolves do not exhibit the same behaviour.
In some places, habitat might be deemed unsuitable if it, for one reason or another, inhibited scent-marking rates (for example, due to frequent disturbance that scares the wolves off the location before they scent-marked and before they investigated the existing scent-marks).
In some places, scent-marks might become destroyed through some human activities and in such places, perhaps wolves also find it more difficult to establish.
If I understand correctly, in the study by Briscoe, B.K. et al. (2002), scent-marking and responses to own scent-marks were modelled on basis of several putative individuals (a pack).
It might be interesting to apply similar models to lone wolves and to wolf pairs in order to see if the response to one’s scent-mark is strong enough to solicit a range formation.
Also, rather than applying only the null model (random walk), it might be interesting to determine whether the number and density of scent-marking posts (e.g., ‘kill sites’) where scent-marking occurs more often, determines the probability of range formation.
Similarly, it might be interesting to see if the presence of neighbour scent-marks affects the scent-marking by the individuals (not from the perspective of the influence of neighbours in determining home ranges but from the perspective of the reaction to neighbours’ scent-marks by increasing one’s own scent-marking rate).
It is possible that a home begins with courtship and dominance as well as with attachments to sites (e.g., feeding sites) because these factors contribute to increased scent-marking rates and to the necessity to find or fight out conditions suitable for scent-marking (which is not the primary purpose).
Thus, home-making might actually be a social phenomenon in wolves (because courtship is impossible without a mate and dominance is impossible without a pack but both contribute to scent-marking).
Attachment to one’s home might, fundamentally, become expressed through the memories represented by the scent-marks (important events and important places as well as important individuals).
The density of scent-marks is related to the rate of memories and relations accumulated and one would be more protective of one’s range when it smells strongly of the stories that have unfolded.
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Sometimes there are groups of wolves that linger in some area but fail to settle.
Usually, the failure to settle is attributed to lack of reproduction which is highly likely because a pack that grows in numbers during winter has a greater chance at truly establishing a territory, especially, in densely populated regions.
However, the settlement might also at last partly arise out of the dense scent-marking that results from using a den site and later – rendevouz sites.
The concentrated use might facilitate wolf attachment to the area and the territory would be expanded during winter due to the need to satisfy the group’s needs that demand a larger range.
Thus, denning behaviour (but not the den site per se) might encourage wolf settlement even prior to the winter territory-defining period.
Notes by Ieva 