Note: So this post is about a race I did Saturday, and the sense of smell, which may not seem particularly closely related, but which together add up to a phenomenally gross thing that happened to me over the weekend. This post also contains a PG-13 tangent which prudish readers may elect to skip over.
Saturday I raced the Garden Creek Gap Road Race up in Southeastern Idaho, about 30 miles South of Pocatello. The course is located in an area of rolling open hills and low, forested mountains, that is one of those countless places in the West you drive by on the Interstate dozens of times over the years without ever exiting to check to check out, and when you finally do, you think, “Wow, this is really nice. How come I never got off the freeway here before?
Tangent: Seriously, why haven’t I gotten off the freeway there before, either around Arimo, or along I-84 and explored the area around the Sublette range? I’ve been to Idaho many times, but always to points North- the Sawtooths and beyond. Southeast Idaho has beautiful backcountry just 2 hours from home, and yet I barely know it…
The race was a bit of a drive, and as it turned out only I and 1 other teammate from the Spin team- let’s call him “Lance”- attended, and as we raced different categories, we each raced alone. (Me in Cat4, Lance in 35B.)
Tangent: When you advance beyond Cat5, it’s a little tricky to race without teammates, particularly if you’re recognized by regular competitors in your category, as I probably am by now. (Probably a dozen know me by name, and I’m tall for a road racer- particularly for a good climber- and Spin has a pretty distinctive, brightly-colored kit.) So you always prefer to have teammates show up. But seeing as my own race attendance has been spotty so far this season, it was probably some sort of karmic payback.
The course is outstanding- an epic climb, a fun descent, fast rollers, minimal traffic and safe, gravel-free turns. I enjoyed the race and finished respectably in 5th place. (Lance took 1st in his category- way to go Lance!) I’ll do this one again for sure. In fact, there was probably only 1 thing I didn’t like about the course, which was that about 5 miles in, after the big initial descent, on a fast level stretch, we hit a couple hundred meter stretch of road that was liberally spotted with cow manure.
NOTE: No, this isn’t (quite) the gross part. That’s coming later…
Tangent: Getting sprayed with manure is only one of countless gross bio-hazard mishaps which occur in road-racing. Race long enough and you’ll eventually be hit by beads of both snot and sweat from other racers. And don’t get me started on pee-breaks cut suddenly short…
Which brings me to the point of the post- smell. Last Fall I did a couple of posts on vision, specifically color vision and foveal vision. In those posts I explained that the sight of birds, as a rule, blows away the sight of mammals, but that among mammals, humans enjoy some of the best-developed color and foveal vision.
With smell, the situation is completely reversed: mammals as a group enjoy a far more advanced sense of smell the vast majority of birds*, but humans are at the bottom of the heap, with one of the poorest noses in the mammalian world.
*Turkey Vultures are probably the only bird I’ve mentioned so far in this blog with a well-developed sense of smell.
All About Smell
In order for you to smell something, a molecule from that thing has to make its way to your nose. When you smell a fruit, for example, it’s because molecules called esters evaporate into the air from the fruit, and some of those evaporated esters have made their way to your nose. Way up inside the nasal passages behind your nose are 2 patches of tissue of a type called olfactory epithelium which are packed with specialized, ciliated neurons. When these neurons are stimulated, they send signals to your brain. Just as your brain has a chunk of real estate dedicated to decoding and processing visual signals, it also has a specialized area dedicated to decoding/processing olfactory signals, and it’s here that the smell is interpreted, categorized and recognized. Things that evaporate large numbers of molecules, like flowers or manure, tend to be easier to smell than things that don’t, like steel.
Just as there are primary colors, there are primary molecules of smell, 7 of them. They are camphoric (think mothballs), musky, floral, minty, ethereal, pungent and putrid. Just as your brain formulates a visual image based on light and colors detected, it also creates an olfactory image, though in humans this “image” is much more rudimentary.
Side Note: Like everything in biology, the details are more complicated. While the introduction above describes the basics of smell, it’s way incomplete. Here’s a quick example: some substances stimulate other nerve endings in our noses, which are sensitive to things like pain and temperature. This is why people who are anosmic (have no sense of smell) can still smell things like menthol. (I suspect anosmics could also smell wasabi, but lack an anosmic friend to take to a sushi bar to test the hypothesis…)
Other mammals use the same basic smell architecture, but in most cases the hardware blows ours away. Our olfactory epithelium contains about 5 or 6 million receptors; an average dog’s olfactory epithelium (pic left stolen from KB’s blog*) contains over 200 million receptors, and Bloodhounds far more. And the olfactory-processing region of a dog’s brain is 4 times as large that in ours, which may not sound like that much until you consider that an entire dog’s brain is only 10% the size of a human brain, meaning that dogs devote 40 times as much brain capacity to smell as we do. A dog’s sense of smell is estimated to be at least 100,000 times as sensitive as a human’s.
Dogs “see” an entire world of smell that we’re blind to. Of course everybody knows they can track days-old footprints and recognize individual humans by scent, but they can also smell whether a frightened dog has been in a room before them, or whether a cow is in estrus. There’s evidence that dogs may be able to smell specific human illnesses, including some types of cancer, and that they even possibly might be able to smell oncoming epileptic fits in children. My favorite analogy is this: if you could smell like a dog, you could smell one rotten apple in 2 billion barrels of apples. Wow.
Although dogs are the favorite champion-smeller example, almost all other mammals beat us as well- rabbits, bears, deer, porcupines, cats- they all way out-smell us. Probably the only major group of mammals with lamer olfactory abilities than us are the cetaceans (whales, dolphins) (though they may have a more advanced sense of taste than we do.)
Meanwhile, Back In The Race…
The Garden Gap Creek Course is 2 laps of the same route. At the end of the lap is a long, stiff climb through the namesake “gap.” The climb broke up the pack, thinning us down to a lead pack of about 10 racers. Together we crested, tore down the backside, turned left, and approached the manure-stretch a second time…
More About Smell
Lame as it is, the sense of smell in humans is still fascinating. Infants appear to zero in on a mother’s nipple by scent; in an experiment where lactating mothers washed a single breast, a strong majority of infants zeroed in on the unwashed breast. And women seem to regularly beat men in smell-tests. Just as the color vision of (at least some) women may be more advanced than that of men, it seems they have us beat in smell as well.
Smell, like vision, seems to deteriorate with age. Human sense of smell seems to gradually improve until about age 8, and then plateau. As we age though, it deteriorates, possibly starting as early as in our 20’s.
Tangent: These last 2 points resonate strongly with (admittedly unscientific) experiences from my own life. First, in the Watcher family, the most sensitive nose clearly belongs to Twin B, our only daughter (pic right, looking a bit edgy just before a piano recital), who will turn 8 this summer. While her sense of smell is impressive, it can also be annoying. If I ever try to sneakily consume a cookie or bit of candy within 50 feet of her she is on me like a bloodhound.
Second, is it just me, or are women who wear too much perfume generally a bit older? I almost never notice a woman in her 20’s or 30’s wearing too much; when I do, it’s almost always a woman in her late 40’s or older. And doesn’t it always seem that guys wearing way too much aftershave are almost always older as well? Sometimes you want to say, “Man, can’t you smell that?” But maybe they can’t…
Another interesting thing about the female sense of smell is that it seems to improve around ovulation*. (Although hormones can’t account for all the difference between male and female sense of smell- the difference is still measurable in young children.) And this leads to the whole issue of pheromones and sexual attraction, and a tangent which you should skip if you’re prudish…
*As does, bizarrely, their sense of hearing. Women hear higher-frequency sounds better around ovulation.
PG-13 Tangent: Years ago in college I briefly dated a woman- let’s call her “Anne.” One evening, in one of those post-intimacy confessional moments in which young lovers so often indulge (and usually later regret), Anne shared with me her greatest turn-on: she had been a cheerleader* in high school, and at the end of basketball games would become highly aroused by hugging the sweaty players of her school’s team.
*No, none of the young women in the photo is “Anne.” I googled for a photo of “High School Cheerleader” and this was one of the few photos returned that wasn’t quasi-pornographic… What a sad state of affairs… I have no idea who these young women are, but they look very nice and well-mannered. I hope their team wins.
Nested Tangent: At the time I wasn’t sure what my take-away from this nugget was supposed to be; in college I was completely unathletic; the only time I broke a fresh sweat was when I was late for class…
As an aside, it occurs to me that there are at least 3 other takeaways from this tangent besides the point I’m getting to (and I am getting to a point), and those are 1) Isn’t it interesting that when we think about a girlfriend/boyfriend from decades ago we may often forget many details about them- their middle name, the music they liked, maybe even why we broke up with them- but we always forever remember the details of any characteristic of their sexuality or sexual behavior/proclivities that was unusual? Think about it- it’s true. 2) It’s always cool when you file away something for years and years and then come across some new information that makes you think, “Oh, so that’s what that was about…” as is the case here, as we’ll see in a moment, and 3) One really ought to err on the side of conservatism when deciding how much to confide in a short-term lover. One never knows where the confessed nuggets will wind up (maybe even on a blog…)
I filed this away under the category of not-really-weird-but-unusual-enough-to-remember for many years. Years later, I learned that there may be some science to support Anne’s turn-on, but the key is fresh sweat, not old sweat. Fresh sweat contains a pheromone called androstenol (C19H30O). Androstenol is a known sex pheromone in pigs and may be- may* be- a more attractive scent to women who are ovulating.
*The science for this one is still pretty sketchy, so it may turn out to be baloney. Then again, it may not. But here’s something else interesting about androstenol: it- or a chemical derivative of it- is a component in the scent of truffles, which appears to be how pigs locate them.
But within a few minutes exposure to oxygen, sweat produces another pheromone, androstenone (C19H28O), which does not appear to be appealing to human females. So old sweat is, well, just gross.
Here It Is
But not as gross as what happened to me next. Our lead group of 10 tore out of the curve and blasted back across the manure-spackled straightaway. In silence, we kept our mouths closed, breathing heavily through our noses. And then it happened- on a heavy inhalation, a small chuck of manure was spun up by a tire in front of me and flew straight up and deep into my left nostril!
Though I grew up in the suburbs, I have smelled cowshit many, many times. I’ve smelled it on farms and in pastures, on roads and trails, and many times I’ve smelled it strongly. But suddenly, for the first time in probably 4 decades of smelling cowshit, I smelled it with a mind-numbing intensity that you simply cannot conceive of if it hasn’t happened to you. The world, my entire universe, was manure. For several seconds I sensed no pain, no race-fatigue, no hunger or thirst, no awareness of anything but the overwhelming, sheer, olfactory brute force of manure.
I blew my nose like crazy. Although the “fecal pellet” was ejected promptly, the stench remained with me throughout the race. Hours later, a shower, nostril-rinse, and bratwurst slathered with raw onions finally seemed to eliminate or mask the smell.
One of my secret, silly fantasies is that for a day- just one day- I could experience the color and foveal vision of birds. Of course it’ll never happen, but I’m pretty sure that this past Saturday, for several seconds, I knew what it was like to smell manure as a dog smells it.