As I walked to the university campus one morning, there were low clouds with a slight mist making odors along the path more pungent than usual. I caught the sweet smell from the geese as I passed the barn, and the penetrating evergreen smell while I crossed into the trees leading to the muskox fence. The muskoxen odors reminded me of cattle lots in the Midwest. My oldest beagle was loose, running a snowshoe hare in the willow thickets on the west forty, her soft baying rolling up through the fog. It's a nice time to let your mind go, without pointing it in disciplined directions. What a vast difference there is between our world views, that old beagle’s and mine. She sees the world through her nose; each check of the hare is marked by the changing aroma. What a psychedelic swirl of odor she must sense as she follows the track. It must be like watching from a speeding car on a winding country road - the flick of fence, weathered sign, livestock and changing landscape, all there, but the road our central focus.
It was the first time I had even noticed the odors in a week or more of walking that path. We humans are surely a visual animal - a thousand different sights and sounds had registered, but until today, no odors. One couldn’t call human beings a mammal's mammal, because from the very first a mammal's forte has been his nose. In the late Mesozoic, when the first things we can call mammals could be identified, they probably scampered through the night guided by their noses, not unlike some of the modern shrews - who hunt myopically, searching for prey, and keep their distance from others of their kind by recognizing the body humors left behind, and tracking down their sex by the female's estrous odor.
For most mammals, odor is the major social avenue. Unlike birds, which have virtually no ability to smell, mammals communicate in a few grunts, woofs, growls, and whines. As many other authors have suggested, primates are more bird-like in this respect because of their arboreal specializations. Scents in the trees have too much dimension and are whisked away by the breezes, but a climber is carried aloft to see and hear well. The highly colored, chirping monkey is what he is for the same reasons as the highly colored chirping bird - because individuals with effective visual and auditory signals left more progeny than those who still emphasized the odor signals on the forest floor.
The living lemurs of Madagascar are an excellent example of primates that use signals of sound, sight, and smell about equally well. The ring-tailed lemur has two specialized glandular areas, one on the forearm and one in the armpit. In aggressive behavior, the ring-tailed lemur's glands are wiped across the arms, and the huge black - and white- striped tail is pulled down the forearms, impregnating it with the smell from the glands. The lemur then faces his opponent and arches his colorful tail over his head, quivering it violently so that the scent is disseminated into the air around him.
The tree-dwelling primates that do emphasize odor often rub the scent (sometimes mixed with urine) on their hands and feet, transferring it to the tree as they move about. Both the slow loris and the capuchin monkey have stereo-typed gestures of anointing their feet and hands with urine. Urine and feces are common scent vehicles; many carnivores have anal glands which add a little musk to each pile of feces. (Interestingly enough, this is the major source of the particularly offensive stench of house cat feces, not the feces themselves.) Mustelids - the weasel family - have extremely well developed anal glands. The skunk group has further specialized these into defensive devices, but like all other anal glands, their original evolution related to their role as a social organ. Some male deer rub themselves with urine increasing their threat signal during the rut. They have prepuce penile glands which scent the urine; like the cat's feces, the stench is more powerful than the urine's odor alone. The dog with the fireplug is an even more familiar example of urine scenting.
There are three parts in this scent display that emerge as common patterns among other mammals: (1) strategic location of glandular areas to aid in odor dispersal; (2) some sort of odor-disseminating device; and (3) a visual accent in the area producing the odor.
In general, the position of social glands is related to the animal's particular life history. For example, some primates have sternal glands (glands on the chest) to mark trees as they climb. Mammals that use runways or burrows more often than not have glands located on the sides to swipe the vegetation as they pass. Deer have lands on the hind, legs that leave a scent on the trail behind them. Pedal (foot) glands are a common mammalian glandular zone.
Almost all glandular areas have elongate tufts of hair to disseminate the odor. In principle they function like an archer s woolen tassel, which hangs from the belt and is used to wipe soiled arrows. The constant rubbing of fiber on fiber, as the archer walks, keeps the tassel clean. The movement of the long hairs of the scent gland on each other wipes constantly and shears the scent molecules into the air as the animal moves.
The function of odor in status displays is not well understood, but what little we do know seems to be sufficient to account for why it arose and how it is used. Much of one's social state depends on being on familiar ground. How often do you get that homesick-little-kid feeling when in strange surroundings without friends or acquaintances near or accessible? When you confront a stranger of unknown social state there is always a certain amount of tension - and the more you have in common, the less strained the confrontation. If he is quite peculiar, the situation is more tense because he may be hostile.
We normally think of visual differences, but the same phenomenon applies to smell. In a tense situation, one sometimes feels even more ill at ease in a building with very strange odors - say, in a hospital, courtroom, dentist's office, or loan office. Familiarity with the surrounding odors breeds a sense of confidence, well-being, a higher social state. Spreading around familiar odors in a place of activity not only marks it as yours - or an extension of you - but also accents the familiarity. Mammals placed in a new enclosure will often scent-mark profusely.
It is easy to imagine how self-specific threat odors evolved. They increased stature; they gave one an edge in conflict where commodities critical to survival and reproduction were involved. In many species of mammals there is a variation of intensity of the species-specific odor with age and hence with status. Puppy urine smells quite different from the urine of an adult male dog. Generally, the young have only a slight threat odor or none at all; the strength increases with age, usually undergoing a marked increase at puberty. The change in odor with age complements the age changes occurring among the visual and vocal signals.
We no longer have special glands with which to anoint our territorial boundaries, as our early primate ancestors did. But in spite of our accent on visual and vocal communication we still have a moderately well developed social scent. We are not too aware of it because of the strong taboos against scent display which have arisen fairly recently.
We all know what areas of the body social odors come from. You have only to look at the deodorant advertisements. The two main zones are in the axillary region, or armpit, and in the area of the genitals. The underarm deodorant business is a thriving industry. Until lately, any mention of the pubic odor was frowned upon; however, with the relaxation of social restriction on both exposure and discussion of "private parts" there are now deodorants being marketed which are especially for use in the genital area.
Part of what we mean by cleanliness is deodorizing, and a moderately large part of our lives is spent deodorizing to make ourselves more socially acceptable - that is, sweet smelling like the immature.
The chief human stink spot, like the gorilla's and the chimp's, is in our armpit or axilla. There are two types of sweat glands there; one form which produces a briny solution is called exocrine, and is similar to the secretion of the sweat glands elsewhere on our bodies. Another type, referred to as apocrine, secretes a mucous substance that is eaten by bacteria - their digestive by-products produce the smell. While the exocrine glands function to regulate body temperature, the apocrine are rather attuned to mood. You have undoubtedly noticed that you need to bathe less frequently in a situation where stresses are low - say with the family in a vacation cottage. But as tensions soar before and during a social performance, the apocrines spew profusely; in a matter of a few hours the rich aroma generated by the thriving bacteria floats up to signal peers.
The tuft of hair over the glandular area is used to incubate odors and to disseminate them into the surrounding environment. Often these tufts are contrastingly colored, producing a visual component to the threat signal. Pictured above are examples of scent tufts as found in Fallow deer, a Tree dassie and a Pronghorn antelope. Like those of other mammals, human social glands are located in areas which are easily disturbed by bodily, movement. The tufts of hair in the armpit and crotch area are rubbed together every time the limbs move, disseminating the body scent to the surrounding air.
To avoid this danger, we jet our underarms with the fizz-can, guaranteed to give protection all day. This deodorant is for the most part a drier plus a bactericide, letting the threat juice flow but remain in its unadulterated form until dry. But the bactericide only lasts so long, and all the while the dehydrated mucus is accumulating. When your deodorant "lets you down," as the ads say, it does so with a crash.
Like the oily glands on their faces, incidentally, the, scent glands of teenagers are also unusually active. It is worthwhile, pointing out that our underarm deodorizing by washing can only be done with the aid of soap. The incubated smelly substance is not soluble in water alone. So even if you go for a swim every day, you can still become overwhelmingly smelly, unless you also bathe. But don't waste your time scrubbing under your little kids’ arms to remove their underarm odors; they aren't there. Like pimples and pubic hair, the apocrine of the axilla doesn't come into blossom until puberty.
The armpit is a strategic area in which to locate a scent gland, because it is the area most frequently disturbed by such a dexterous biped as apes. The tuft of hair located there functions in a way similar to the glandular tufts of other species. The tassel rubs and moves on to itself to disseminate the aromatic molecules, but at the same time it increases the surface area in that steamy, warm cave, so more bacteria can live and eat faster on the apocrine juices.
Genital odors have a somewhat more complex evolution, but the principle is similar. The "corn-silk" crotch hair functions like the hairy axilla, as a scent holder and disseminator. Again, it is located in a strategic position to be disturbed by movement.
What has happened is that a scent source has also been modified into a visual signal source as well. Evolutionary modifications of this type are common. The hair-tuft glands of many mammals are frequently a contrasting color to their surroundings. The tarsal gland patch of deer with lightly colored legs is dark (moose), and deer with dark legs have white tarsal gland patches (caribou).
The genital area, then, affords the observer with a quick estimate of sexual maturity in an unclothed society, with all the sexual implications thereof. Crotch hair probably originated among human ancestors as an odor disseminating spray of hair around the anal-genital area - but once it also assumed a visual clue to rank, it extended up-ward fanning out over the lower abdomen, forming the pubic patch. Unlike the corn-silk axillary or anogenital tuft, this pubic patch became more dense and matted, like the hairs of the beard.
The visual role of axillary and pubic hair can be seen in some expression of human behavior in Western society. Women often shave the axillary hair to effect the pre-puberty look. In photographs and illustrations designed to arouse erotic feelings or aesthetic emotions about the human body, crotch hairs (and most other body hair, for that matter) have usually been airbrushed or omitted from the picture.
Social odors in other animals are used primarily for status communication, though there are many cases where special odors are used as sexual lures as well. Our human odors are used as sexual from the axilla and crotch arose primarily to give an aromatic accent to status well back in our evolutionary past, and have been retained for that same function. Their offensive character is not inconsistent with other threat, signals - when they become concentrated. On the behavioral side, we label offensive and vulgar any dominant who flaunts his superiority in a belligerent manner.
Some of our cultural shifts throughout history have complicated our ancestral use of odor in communication. Our increased population congestion has made body odors more of a problem, and because of this forced intimacy we have ritualized deodorizing behavior. As a result we are less familiar with body odor in our present culture.
As societies became complex enough to place the high dominants in a clean non-working class, the stench of body odor became somewhat reversed as a clue to status. The non-working gentleman could bathe more often and reduce other coarse signals form the past. Status could now be signaled by other things, such as membership in groups and conspicuous consumption. The heavy brow, broad shoulder, and rank smell stood for success in another era were transformed and became the property of the propertyless, who had to support the delicately clothed, fine-boned, dominant gentlefolk. Hairy genitals and smelly sweat became uncouth. Important threads from our distant heritage, however, still remained: the awareness of genitals from hurried glances in the locker room, joshing at the swimming pool, the guy squeezed up against to in the subway.
The evolution of glands in the genital area is much more complex than those elsewhere on the body. It isn’t just the scent of the mammalian body that is important, but also the scent remaining when the animal is elsewhere. In addition to material rubbed directly from the gland itself, the secretions have evolved to anoint various body excreta. The musky odors on urine and feces have been an important mode of mammalian communication. They communicate relative status and estrus condition (when female animals are in heat) but mainly status.
The preputial flap, the foreskin covering the glans penis, the labial area of the female vulva are common locations of glands that mammals use to taint their urine. Some hoofed mammals have special hair tufts on the prepuce that appear to function in a manner similar to the glandular tufts we have already discussed, mainly as olfactory incubators and disseminators, with visual overtones.
Humans still have glands in the prepuce and vulva areas, though they have long ceased to fulfill any urine-marking function. They do add to the smells of the body, and if not cleansed properly become potent aromatic centers. The preputial flap might even be though as a gland itself; the bacterial activity on the secretions is so extreme as to generate a white, cottage-cheese-like by-product.
The ritual of circumcision that has gained almost universal acceptance in the Western world could be thought of as a glandular amputation to eliminate the stinky slime of the key threat center.
There are considerable racial variations, as well as cultural attitudes concerning the quality and quality of odor productivity among human beings. Orientals in general have poorly developed scent glands, which are large and varied in Caucasoids and Negroids. It is commonly remarked by American soldiers who have served in Asia that native women think they stink. In a syndicated newspaper column, a reader recently asked why Japanese girls had this opinion of American men. The reply was that American men eat more meat, which makes their sweat stink. Yet some Orientals, like the Eskimos, eat mainly meat and do not have the musky underarm odor of Caucasians. We still can’t admit to group differences, because that somehow implies inherently different values.
As is true for other organic features of status (like beards and square jaws), the full brunt of the scent signal is offensive; yet in dilute form it is attractive.
Like the others, he stank of rancid fish oil, the ointment the braves used before battle. The massed odor, sweeping over the watcher like a visible wave, left his senses reeling. It was a savage odor, old as man himself.
Slaughter, Fort Everglades
I recall the scent of some kind of toilet powder - I believe she stole it from her mother’s Spanish maid - a sweetish, lowly, musky perfume.
Nabokov, Lolita
In their more subtle dilutions, human body odors are rather pleasant. Many perfumes are derived from musk secretions, but diluted to a level where their resemblance to the odor from our rancid musk glands is difficult to recognize.
So long with the false contours of beards we can add other functions of human hair patches - scent tufts. Next, another use of the hair: as a specialized eye ornament to signal status based on size, a more specifically, height.