jtotheizzoe:

What do you smell like? I mean, really smell like? And WHY do you smell like you smell like?

The natural odors of most animals, besides those like skunk musk, are actually a result of bacteria digesting certain secretions and releasing tell-tale scent compounds. When dogs smell each others’ rear ends, they aren’t really smelling each other (so to speak), they are smelling the characteristic odor products.

But why? The obvious reason is that it provides an odorous fingerprint, a tell-tale tail-tell. Dogs, primates and many other animals smell each other to identify strangers from those they know. Do humans do it? We evolved off of all fours long ago, so having scent glands “down below” wouldn’t do us much good, unless you wanted to bend over in the street to say hello. But we do have quite a garden of smells going on up above, in our armpits and chests.

It turns out that people can be identified by their chest and armpit bacterial odors using an “electronic nose”. It also turns out that we think people with more diverse immune genes smell better than those who are genetically closer to us, a sign that we use our nose to pursue genetic diversity. And most women can tell you some tale of sensitivity to smells when pregnant or ovulating. Some research even indicates that we can smell sick people! Is this why we nuzzle our noses into the napes of necks when getting romantic? To test the smelly waters?

And what about our species’ proclivity toward perfume? Here’s what Rob Dunn theorizes:

Then there is a final piece to this story, the issue of subterfuge. Very early in our human history, we began to take advantage of smells produced elsewhere in nature to perfume our bodies. We think of perfume as lovely in moderation, but there is another way to think of perfume, as a way to cheat. When you apply deodorant or perfume, you are covering up the odors produced by your bacteria with an odor regarded as pleasant, at least to the conscious brain and perhaps, if the perfume and deodorant companies have done their jobs, to the subconscious too, which is important since that seems to be where the decisions are being made¹¹.  I’m not sure where this leaves us other than with the impression that nearly the entirety of modern humanity has figured out how to smell like a peacock. Beware both the wolf in sheep’s clothing and the Gonorrhea that smells like Old Spice.

For more, check out: Sick People Smell Bad: Why Dogs Sniff Dogs, Humans Sniff Humans, and Dogs Sometimes Sniff Humans

(via Scientific American)