Scent marking and scent signal readings in mammalian species have so many functions and expressions that it is difficult to tackle these intricate correlations in one post.
However, I would like to address an aspect of scent processing behaviour which is that of rolling in scent which might have been deliberately (with communication purposes) left by oneself, by a conspecific (of the same social group or non-affiliated) or which might have non-deliberately (without a scent signalling intent) ended up in the environment (e.g., carrion, excrement that does not serve communicative purposes etc.).
I have partly discussed the aforementioned phenomenon in my earlier post – Rolling in deposits by other species – immunity-strengthening behaviour?
In this post, I would like to propose a theory that rolling in scent might be a form of self-medication with respect to one’s mental health and performance which could be likened to aromatherapy in the human world.
I arrived at this idea watching wolves rolling in various types of putrid, excretory etc. substances.
It must be difficult to ‘be a wolf’.
Namely, as wolves need relatively large amounts of prey but their prey is distributed widely in the landscape and often actively avoiding encounters with the wolves, wolves must travel a lot in order to even find their prey and then they must test them for their vulnerability.
The hunting success is not that high in wolves (5 – 28% according to Living with Wolves) while their diel activity duration is rather long (e.g., ca. 10.8 hours of undifferentiated activity in Białowieża, Poland (Theuerkauf, J. et al., 2003) and ca. 8 hours of active walking on Isle Royale, USA (The Wolves & Moose of Isle Royale).
Often wolves only kill their large prey every 3 or so days.
This would suggest that whenever the wolves are ‘on the move’, they are actively processing sensory data (smells, audial cues, sights) in order to detect the presence of prey.
And almost as soon as the kill has been made, wolves have to be on alert once more to obtain the next meal.
Accordingly, I find it easy to imagine that, on daily basis, wolves might feel rather overwhelmed with the continuous sensory processing that pervades almost all of their activity (apart perhaps from the rest period immediately after having fed on a freshly killed carcass although one has to be on lookout for predators as well as perhaps apart from the playtime near the den or the rendevouz site which is a relatively safe place although adults have to be protective of the pups against predators).
The world of a wolf is probably very intense and it could be compared to us walking through a town which is full of signs that might be of personal relevance to us and that have to be processed actively (because I find it unlikely that wolves instinctually ‘float’ through their environment only ‘awakening’ when an important signal has been received; wolves have to make active decisions and upon noting signals, they have to be able to react instantaneously and according to the very specific situation).
It might not be easy for wolves ‘to unwind’ and to rest their brain.
While it might appear that adults are under greater pressure than pups, I believe that pups are introduced only gradually to the ‘unlimited world of stimuli’.
It is certainly true that pups do not travel with adults by autumn because pups are not able to cover such long distances at such great speed during their summer stage of development.
However, it might also benefit the pups to become exposed to relevant sensory stimuli step by step – in a familiar environment when new and crucial scents (scents of prey) are brought home and explored against the background of a familiar scent setting.
Thus, when pups begin accompanying adults, they are not overwhelmed and they can retain focus because in the wide world of confusing smells, they already can recognize those that matter most (scent of family, scent of food, scent of immediate danger).
Both pups and adults might be in need of ‘taking a break’ at times, and rolling in scent which is, for example, familiar or pleasant (from a wolf’s perspective – reminding of good meals and full tummies), might be akin to having a bottle of beer (in the case of adults, of course) in order to be able to switch off one’s alert mind and to relax a little.
Carrying this scent on one’s coat might prolong the exposure and the individual might be able to have their sensory experience briefly dominated by familiar stimuli that send signals to the brain inducing production of ‘happy hormones’.
Wolves and other mammals roll in many different types of scents which might not always provoke pleasant associations (e.g., scent of competitors or scents of neutral import which are, however, strong and enticing).
Studies that have been conducted to evaluate the effects of fragrances on human brain suggest that scents can stimulate one’s overall performance, excite oneself, deactive certain brain functions, increase alertness of drowsiness, reduce attention, arouse psychosomatic responses, induce a sense of tiredness, produce sedative effects, awaken a sense of comfort and relaxation, interact with memory pathways (stimulating or repressing working memory), influence the processing of motor response etc. (Sowndhararajan, K. & Kim, S., 2016).
Essentially, different aromas (combined) can stimulate or repress all of the brain regions and have impact on all human brain waves (although, of course, specific fragrances only affect certain regions and waves).
From the list provided it is possible to determine that aromas can be used to temporarily activate or to deactivate one’s physical, psychological or cognitive functions.
Also, it might be important that resting states are not necessarily linked with reduced activity – one can feel relaxed and alert at the same time (namely, if a wolf induces certain states in its mind and body during travel, it does not necessarily result in lower prey-tracking performance; it might simply reduce some of the accumulated data load impact).
These examples also show that individuals might be using scents not only to ‘unwind’ but, on the contrary, to stimulate themselves which could be important if the wolf was somewhat tired or the wolf’s motivation was wavering.
This could be of particular importance for pups during their first weeks/months of full-time group hunting.
The impacts on memory should not be overlooked because wolves create cognitive maps of their territories and within these maps they have to know their location, they have to recognize territorial boundaries and they have to be informed on where the prey might be located, seasonally.
Similarly, scent rolling (and the presence of scent) might induce other types of memories (social memories) that encourage cooperation, affiliation, social interactions of bonding nature and that might reduce aggression and promote a good feeling in the social group.
I find it cute and interesting that European badgers often mark one another.
European badgers are supposedly only developing a social living and they forage solitarily.
Meanwhile, if they carry the scent of their group with them, it might remind them of their social group or even protect them (perhaps a badger that smells like itself but also like another badger and like its entire group can cause greater respect in a potential competitor or predator because it is more difficult to assess how many badgers, precisely, there are around at the time).
I would prefer to think that badgers are taking the scent of their buddies ‘to work’ and ‘to sleep’ and that it is important for the badger not to loose touch with its group entirely even when not in physical contact (and when physical contact/proximity is not desired by the very individual).
The badger might not undergo ‘social shock’ upon returning from its solitary ventures and reuniting with its group if the scent of the group has been with the badger all the while.
Rolling in the scent produced by the entire group (e.g., river otters in North America) might stimulate the animal to feel or to perform above its individual motivational capacity (like singing a song together to feel inspired on a collective level).
It might also serve the purpose of recognizing oneself as a part of the group.
I believe that self-identification in many animals occurs through external mechanisms (e.g., social mechanisms but also sensory mechanism) and scent rolling in one’s own scent or scent rolling in one’s own scent that has been mixed into the scent of others (one’s social group) could allow the individual to self-identify within the group.
Similarly, juveniles might scent roll in the scent of adults in order to compare their own scent with that of the adults in order to determine their state of maturity (do I smell like a grown up already?).
Perhaps scent rolling in the scent of ‘an enemy’ might also result in a no-contact power-matching (comparing the health or hormonal etc. status between the individuals and making respective decisions).
Rolling in an unfamiliar scent might also serve as taking a photograph in order to prolong the exposure to the stimulus and to see if it any associations/memories are provoked at a later time as the brain constantly processes the strange smell.
This could help determine ‘what it was I discovered’ when it is dangerous or impractical to linger in the spot where the scent was found.
In this case, it could be a memory trigger which is normally not associated with aromatherapy but I have expanded the context toward other types of cognitive processing and social behaviours.
Certainly, I have only touched upon the possibilities that scent rolling might represent but it is a beginning to unravelling the mysteries of why animals roll in different scents.
References
All about Wolves, The Wolves and Moose of Isle Royale, https://isleroyalewolf.org/overview/overview/wolves.html
Dutcher, G. DID YOU KNOW? Wolves do not kill for sport, Living with Wolves, Sep 15, 2020, https://www.livingwithwolves.org/killing-for-sport/
Sowndhararajan K. & Kim S. Influence of Fragrances on Human Psychophysiological Activity: With Special Reference to Human Electroencephalographic Response. Sci Pharm. 2016 Nov 29;84(4):724-751. doi: 10.3390/scipharm84040724. PMID: 27916830; PMCID: PMC5198031
Theuerkauf, J. et al. (2003). Daily patterns and duration of wolf activity in the Białowieża Forest, Poland. Journal of Mammalogy – J MAMMAL. 84. 243-253. 10.1644/1545-1542 (2003) 084<0243: DPADOW>2.0.CO;2.
Notes by Ieva 