AS A naturalist, the use of my olfactory skills is something
I’m rather proud of – I can smell, or at least notice the smells of, things that many who walk with me will regularly miss. I once detected the pheromone of a female lackey moth on a walk; it was an odour unfamiliar to me and I deployed my eyes to search out the source – an investment of time and effort not many would bother to make.
A simple exercise in awareness will bring even the most urban human up to a pretty high standard very quickly (as you will see later on in the chapter). Some folk seem to have special skills but I believe we’re all capable of a lot more in the smelling sense if we could be bothered to put our nose to it.
One lesson regarding this under-appreciated super-sense was taught to me in a most surreal setting.
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‘We’ll start now, if you’re ready.’ A kind, soft, feminine voice, with a hint of the American Deep South, percolated through my headphones, signifying that the experiment was about to start. I was taking part in a filmed experiment, a guinea-pig participant in a scientific demonstration exploring our sensory abilities. The details of what we were doing, I was informed, would become apparent in time. For the time being, I had been told that I had to trust my production crew implicitly. I couldn’t know why I was there or indeed even the nature of the experimental procedure; just knowing this would bias my responses.
Minutes before, I had entered the modern brick stark-looking building with the words ‘Monell Chemical Senses Center’ in gold letters above the doors. There was a clue to my immediate fate in that name, as there was in the large golden sculpted representation of a human head peering out of the wall and looking – or perhaps sniffing or listening – at me as I entered, but as to the finer details I was in the dark.
Well, actually, I wasn’t, I was sitting in a six-by-six sound-proofed cupboard. There was a computer screen, with keyboard and mouse in front of me. There was no window, just a door that was now shut firmly behind me. The sucking noise it made as it closed again confirmed that if I was inclined to scream, nobody would be able to hear me. All that connected me to the world outside the room was the umbilical cable of the comfy headphones I now wore clamped over my head and through which I was about to receive my instructions. A remote camera was in place in the corner of the room to film my reactions.
The whirr of the air-conditioning unit in the ceiling ceased and the test started, a not-too-taxing series of simple questions asked by the gentle voice in my ears about various scenes and visual tests delivered to me via the computer screen. After twenty minutes or so, the session finished, and I was allowed out of the quiet cubicle for a coffee. Apparently, I was a quarter of the way through the test. The second session was very different – the experimenter’s voice was ragged, impatient, rude and at times quite derogatory and insulting. If I got one of the questions wrong, I was berated. I felt stupid and horrible. The air-conditioning fan came on and I left for lunch before another two sessions in the sound booth. I was dreading another humiliation, another earbashing, but for these final two sessions the voice was calm again.
When the experiment concluded, I was finally introduced to the experimenters. Who apologised for being so horrible to me before explaining that the torment and the psychological trauma was all part of the experimental design and that they were testing my ability to pick up on highly dilute odourants in the air, at levels that can only be detected subconsciously. So what had they been doing to me? Well, the first session had been a kind of control to see how I would perform under normal conditions, the questions were easy and the questioner’s attitude was a kind and compassionate one; the second test was the opposite, designed to be harder. These questions were very taxing, and the derisive voice was aimed to give me a negative experience. In addition, they had pumped into the room, while I was having my coffee, a very low concentration of an odourant – I was told it was a substance extracted from a rare pine, found only at altitude, a specific smell that I was unlikely to come into contact with in everyday life. My brain had now, like it or not, been conditioned to associate this dilute odour with a trauma. After lunch, we had another two sessions – these tests were designed to be equally taxing, the only difference being that while I was taking part in the first one, the pine odour had been pumped into the room. Guess what? The outcome was that, even though I should have performed comparably well in both tests, the one with the odour of the pine tree present put me on edge, my heart rate was elevated, my ability to concentrate and cognitively function were compromised. The pine odour had somehow become so entwined with the negative emotions I had experienced when I was first exposed to it that I had formed an olfactory memory.
It is thought that this sensitivity and ability to make such connections in our subconscious could have a bearing on all sorts of human conditions, including post-traumatic stress disorders (PTSD). The fact that you might not even be aware of the trigger for the change in your emotional estate might also explain those situations in life where, for no apparent reason, you are set on edge or get a feeling of unexplainable foreboding. A few parts per million of a volatile chemical could be all it takes.
It says ‘pine fresh’ on the tin. I give the aerosol a little curious squirt. It doesn’t smell much like a pine forest to me, but there is something in it. Sadly, a toilet air-freshener is the most aware many of us will ever be of the natural ambience of odour. Take a walk in a real pine wood and you get a genuinely fresh smell, but what exactly is it? Why does pine smell like it does? Which bit of the pine is smelly, from where on the plant does it emanate?
As you pass through any environment, you are not just pushing through or breathing in air; that ratio, learned at school and quickly forgotten, of 78.09 per cent nitrogen, 20.95 per cent oxygen, 0.93 per cent argon and 0.04 per cent carbon dioxide, with a little water vapour thrown in, is, thankfully, an over-simplification of the reality. The stuff that creates memories, fires the emotional part of your brain, stirs up deep and evocative thoughts and gives you millions of clues about what is all around you every time you inhale is also mixed into the sterile definition of the air you breath. What’s more, these particles of other chemicals are bouncing around in varying concentrations, some released steadily by biological processes occurring all around us, such as the leaf litter, the soil. Others are more discreet, they waft up in clouds, concoctions with purpose: the scent of sex, anti-predatory strategies of plants and animals, a decomposing thing unseen in the bushes, a deceptive lure, an advertisement from flower to insect. The very air we breathe is a communication channel for so many living processes that it would be remiss of someone on a self-rewilding journey to ignore it. We live in cloud of smell, an invisible soup of volatile chemical influences.
We’ve seen that we’re capable of smelling so much more than we might think, and it has been proven that by consciously and mindfully drinking in particular smells you can improve and train your abilities. In the same way, we’ve demonstrated that, just as by being hyper-aware with your sight and hearing you can really open up your sensory horizons, the same can be done with scent.
Natural scent, odour, malodour, odourant, smell, call it what you like, is produced by everything. As with other forms of non-visual sensory stimulations that don’t engage with our primary sense of sight, I end up using my inner eye to explain it. This does follow some kind of logic if you think about what odour actually is. Although the volatile chemical compounds that we register as odourants are invisible, they are still physical entities, they are particles, albeit very small molecular ones. It is these that make their way into your nose and tickle the sensitive hairs in your olfactory bulb. I find it helpful to imagine them and how they get there.
You might be walking along the edge of a field, it’s early on a December morning, it’s cool and damp, the air is still. It’s a perfect day for smelling a smell. Then you get one. A sudden whiff of something powerfully musty, you’ve penetrated a cloud of it, a split second and you’ve passed through it. You stop and retrace your steps backwards and there it is again, it’s a finite and physical thing, this cloud of odour; it has edges.
Combine a few of your other skills and you might find more clues as to the nature of the smell: a phantom trail in the dewy grass, a distinctive footprint in the mud, maybe some displaced vegetation or a hair snagged on the wire fence under which an animal has passed. Get down on your hands and knees and the smell will get stronger. It’s the pungent aroma of a fox. Most of us have smelt it before, whether you know it or not. The problem is, I have no words to help you out here. Fox smells like fox – you need to have first-hand experience of a fox or for the knowledge to have been passed down to you to know for sure.
I know the smell of fox because I’ve been lucky enough to have smelt one. The first time I unequivocally smelt fox was one of the many seminal reference points that I had growing up in a rural location. I remember it clearly. I was helping my dad out in the garden. It was while I was on my hands and knees pulling up fistfuls of groundsel and shepherd’s purse. Tearing them up by the roots, clearing the potato patch ahead of my dad’s systematic clod-turning fork.
This was nothing special for me, it was a regular, routine situation. I was probably complaining at the time, too, as this would have been a chore and I was probably bribed by the promise of a little pocket money to blow on a paper bag of sweets in the village later.
As we cleared and turned the vegetable plot, my dad would point out anything of interest while we worked; a clever tactic aimed at holding my interest in the task. Most usually this would be specimens of earthworm which were plucked from the freshly turned sod and placed in his bait box for fishing. But sometimes other creatures not destined to be dangled in front of a trout. There was plenty to hold my typically short attention span in the dark, fertile tilth. Myriads of creatures scurried from the light – subterranean centipedes were always a favourite: like marmalade-coloured string they would ripple their legs in reverse to back up into the loam from where they had been woken. There were turgid and pale cockchafer grubs and the grumpy, dry toads under the old scaffold planks Dad used as tread boards. But on this occasion, there was something tangy in the air, something of interest but not in my usual visual dimension. There was something that made my nose wrinkle. ‘What is that horrible smell?’ I asked.
‘Fox,’ Dad answered. How did he know it was a fox? I guess he had the same information passed down to him by an elder family member too, the way knowledge creeps down through the generations. This was a ‘boy’s own’ kind of knowledge. The sort of thing nobody would teach you at school.
Dad went on to explain that a fox had probably been mooching around the garden last night, his fancy tickled by the smell of our free-range ducks and chickens. I felt the prickle of excitement. Foxes were (and still are) exciting to me.
Just over the field was an old sandpit quarry, now referred to simply as ‘the dump’. Here generations of villagers and the farmer had discarded their junk. Occasionally, I would catch a fox here, sunbathing on the roof of an old rusted-out Wolseley that slowly senesced amongst the bramble and elder, a machine returning to its fundamental elements. The fox perfectly blended in with the roof of the old car and it was only that unerring sense that something was watching me that first made me look up. Then my eyes met Reynard’s; I was looking through amber windows straight into the un-tamed spirit of the land. The countryside surrounding me might have looked tame and cow-towed to the hand of man, but when I first looked into the furiously indignant eyes of a fox, I felt it: wild was very much alive in an animal of survival; a creature of wisdom, cunning and resourcefulness living amongst us. So to think that that rusty streak of wild was sliding around just a few metres from my bedroom window while I slept thrilled me; it was as if I was right all along: magic didn’t just exist in fairytales, it was here all the while, unseen – but not, as it happens, unsmelt.
From this moment on, the smell of fox has stuck with me. It has cloyed to my working senses and when I pick up that tang on a walk, I immediately look around for further clues that back up the nose and usually I find them. I can imagine that shadow sliding around field margins and crossing the path where I now stand, the fox’s trot hidden by the high grasses and herbs, his odour floating on mist and dew, pulled by an invisible thread into thickets that would hide the fox from our primary senses – however, with a sniff and a memory, he’s busted.
If I drop down to fox level and get closer to the scent, it gets stronger, and, to mix my sensory metaphors, it gets louder in my nose. That is because I’m getting closer to the source. So what is the source? It’s rarely the fox directly as he’s long gone, although at this time of the year sometimes you can pick out a sweeter smell, if your paths have only just crossed. It’s produced by a gland on the top side of the tail; it’s a gland that wafts its volatile secretion directly into the air. The source of eau de Reynard, familiar to dog owners, is known as the violet gland, a name given to it because of the odour’s heavily poetically licensed resemblance to the smell of these flowers.
The odiferous signature of fox – well, at least the predominant smell I can pick up – is a mixture of things, but mainly it is a little puff of urine, a sprinkle here and a dribble there. Just as our slow loris smears its world and walkways with urine, so does the fox. It’s a habit that is strange, if not unhygienic, to us but it’s essential to the social and sexual life of many mammals and it is one familiar to lead-tugging dog walkers. The messages in these vaporous communications are untold, but at least some of the conversation can be heard if we pay attention to smelling it. The cloud of fox vapour tells me he passed this way – and it usually is a he, females have a smell too, but nothing quite compares to the strength of odour in male fox urine.
It helps to think of it as any perfume. It’s a dab somewhere on the vegetation, on a tuft or tussock, sometimes added to faeces, but it is a finite quantity and, from the moment it’s deposited, volatile molecules of smell detach themselves and are wafted away by the breeze. The conditions that these scent marks exist in very much determine how long they last and how strong they are.
The still air on a morning walk means that the smell of a fox is strong, it’s probably only a matter of hours old, so it’s fresh; there are still plenty of volatiles leaving the original deposit, but the fact that the air is still cool means not only that it has not started to rapidly dry out and evaporate, but also that the other air particles they are mingling with have not started to liven up too much. That cloud of scent is still a cloud because the air has accumulated all of the particles that have torn themselves away from the spot of urine; each one hasn’t got very far in its journey or random dispersal.
As the sun rises, the air warms, resulting in the molecules of gas picking up more energy. When they do this, they start to dance around more; they bounce around, spreading out, colliding with each other, and this has the effect of rapidly shuffling up the scent molecules and speeding their distribution and therefore our ability to detect them. Most saturated and humid air is pretty good at holding on to smells too – the niff of slow loris, tapir or macaque clings to the air, while the smell of decay and flowers always seems to be more concentrated in the tropics and this is probably the reason why: the wetter it is, the slower these volatiles evaporate and disperse.
This lesson learned from the fox is one that applies to all of the smells we detect. The process is twofold. As with any sensory awareness, we need first to notice the smell. This requires a deliberate effort to go out of your way to smell something in the first place. It’s an exercise that is familiar by now, it’s how we’ve trained and exercised our sight and our hearing. But, secondly, it is through giving the sensation a place in your thoughts – building a registry of connections that somewhere in your existence, you’ve tasted and smelt – and sometimes both at the same time (as the two senses are very close to one another and some would argue are even partly the same thing) – these ingredients separately. You’ve laid down a reference point, you’ve got some kind of memory.
A bottle of desert rain
So to become a more complete human, one that is fully installed in the unbridled potential of your own body, you simply need to build more reference points, and gain more experiences via your nose. This can start right now.
Vegetation is probably the primary source of natural, environmental redolence, and it is probably more important to us in recognising and gaining a sense of place than we at first realise. I want to take you away from the bottled ambience of pine-fresh room deodorants and their brutal assault on the senses to a world of smells, many of which are very difficult to bottle, except one.
On the rare occasion that it rains in the Sonoran desert, the air fills with what the locals might refer to as the smell of rain; it is the smell that accompanies the suppression of dust, a clearing of the air and usually an explosion of animal and plant activity. It’s a smell that triggers exaltation among the desert’s human and non-human residents, which rejoice in the abundance of this usually scarce life giver.
To find the source of this smell is difficult and it eluded me for years. During the rain it permeated all and when it was dry, it was lost in the searing heat, where the air seems to almost burn the interior of your sinuses into a parched papery submission. I had assumed that the smell was atmospheric, that it was the smell of ozone, that rare triad of oxygen molecules often generated by lightning strikes. I had been in many thunderstorms in my time but I had never smelt anything like this before, outside the desert. To be honest, I hadn’t really started waking up to my olfactory perception. At this point I was nose blind; I could smell the coffee but I was far from awake to its potential.
It wasn’t until I had a chance encounter on a desert trail not far from Tucson, Arizona that the mystery was solved. I was out walking early one morning, trying to get the most out of the day before the searing heat of the sun made being anywhere out of a pool almost unbearable, when I bumped into a Tohono O’odham man, out and about doing the same thing. When the conversation turned to the creatures that I had been seeing on my hike, I very quickly realised that I was in the presence of someone born and bred in the desert who had a deep love and connection with all it contained. It was during our informal chat that the question of this smell came up, as it had rained a few days previously.
His answer to me was to walk a short way off the trail and gently grasp a branch of a spindly bush and rub a few of the sparse tough little leaves between his forefinger and thumb. He gestured for me to do the same and then to sniff my fingers and there it was, right under my nose, the smell of the desert in a deluge. Locked deep within the cells of the greasewood or creosote bush, imprisoned within the waxy leaves in a cocktail of aromatic oils. These oils fulfil many tasks: to make the foliage unpalatable and to reduce predation on the leaves, to suppress other plant growth and to guard that most precious commodity in the desert environment, water. Usually these same oils are held captive but a good soaking of rain, or the friction of a thumb and forefinger, and they are liberated for all to smell.
I must confess that to this day I have a little sprig of creosote bush leaves in a glass vial. When I want to be spontaneously transported the five thousand miles back to Sonora, to sit beneath the towering Saguaro cactus, hear the dry buzz of a rattler’s tail or the scolding of a cactus wren, all I have to do is pop the lid, shut my eyes and gently inhale.
This phenomenon is not restricted to the deserts of the American Southwest. You can smell the rain almost anywhere that experiences heat combined with sporadic rain. It’s not the same as the distinctive aroma of the Sonoran desert, but it does have enough of a similarity to make you suspect it shares a common chemistry.
When rain has fallen on a landscape that has undergone a period of prolonged drought, something happens. I’ve smelt the rain like this in the red centre of Australia, in the Serengeti and in a Tesco car park in the middle of a summer thunderstorm – places where there isn’t a single scruffy greasebush to be seen.
The smell of a landscape is often released by rain, it’s such a noticeable phenomenon that it even has its own word, petrichor – derived from the Greek words for stone and fluid, or blood. While this has been wholly attributed by some to the production of ozone during lightning storms, the variability of the smell suggests otherwise. It’s neither the water nor the ozone, both of which are fixed in their structure and molecular make-up, but a combination of molecules as unique to the landscape as its geology and the species on which the rain falls.
Different intensities and odours suggest that the smell is of a place, it is in effect the essence of the landscape itself. Something in the living landscape lifts away from its earthly tethers and, for a limited time, cavorts and gambols, albeit for a brief moment, in another gaseous element, before shooting straight up your nose.
When you smell the petrichor, you’re smelling not the rain but the landscape itself. Just like the distinctive and unique oils in the greasebush found in the American Mid-west give the desert its post-rain smell, other plants’ oils also contain and utilise varying combinations of similar oily, volatile and aromatic compounds such as terpenes, limonene, camphor, methanol and 2-Undecanone, to name a few. During rain, these oils, many of which drip down over the course of the life of a plant and find their way into the soil, along with a substance called geosmin (which literally translates as earth smell), a waste product of soil-living bacteria, combine to form distinctive-smelling aerosols.
Bubbles of air released from the saturated soil percolate upwards and in doing so initiate the process of picking up and liberating these various oils and metabolic acids into the air – the result is an environmental odour cloud, unique to the species of bacteria and greenery found there.
You don’t have to wait for the rains to appreciate these smells. If I had crushed the creosote bush leaves first myself as part of a more complete exploration of my desert walk, I would have identified the smell of the desert first-hand without the need of some local wisdom. Nowadays, and as a direct result of my Tohono O’odham lesson, I like to create my own sensory wisdom and enrich my own experiences.
As I walk, I’ve now developed a habit of plucking at the leaves of plants as I pass them on the trail and rolling them between my thumb and fingers to release the chemistry within. By investing time in my sense of smell like this I create many extrasensory connections. Some are conscious while undoubtedly others will be filed away in my sensory memory banks. At one level it is a simple pleasure, like enjoying a sunset is for your eyes, or listening to a nightingale is music to your ears, but drift a little further into the world of smell and you’ll discover a world of practical applications.
I need to give a word of warning here: at this point it is preferable to apply a little bit of local information and that other inward wit, common sense. At home, I don’t make a habit of grabbing, say, the leaf of a stinging nettle or a bramble – as I know, or, more critically, I’ve learned, that these plants are not as innocuous as they look and are capable of fighting back. The day I grasped at one of the soft heart-shaped leaves of a stinging bush in Western Australia was the first in a week of agony and sleeplessness, with a fire on the skin that seemed to be revived every time I sweated or took a shower. I’ve repeated the mistake with poison ivy and poison sumac in America as well. It’s not always chemical either: while you are unlikely to grab something that looks thorny or harsh to hold, some grasses and ferns have stems that contain silica and can cut like a razor when drawn between the fingers. I guess there is no faster way of learning what not to touch in the future!
What you learn, whether via an odour, an unpleasant chemical reaction or a good old-fashioned pricking, is that in the process of crushing leaves you will develop a deeper sensory insight into the environment. By using your sense of smell as part of your routine explorations, you begin to train your nose to notice. When you start, you’ll be surprised what you tune in to. It’s such a part of the ambience of an environment, and to realise the scented signature of a habitat gives you as much a sense of place as any other sensory stimulus and sometimes even more.