By Richard Conniff/ NYT

One of the odder things about perfumes is how much they have depended over the centuries on the scent of other animals — for instance, ambergris, a fatty excretion of the sperm whale, or the musk from the anal sacs of a civet. In concentration, some of these scents are unpleasant, even noxious. One component of civet is skatole, literally the smell of animal feces. Why not just make up a cologne called “Hyraceum — the Ultimate Code of Seduction,” advertised in a suitably libidinous whisper? The fine print would reveal that Hyraceum comes from the petrified excrement of the Cape hyrax. (Oh, but it turns out Hyraceum actually exists, at a very reasonable $60 an ounce.)

We are by no means the only species trying to smell like something (anything) other than ourselves. The caterpillar of South Africa’s Zulu Blue butterfly, for instance, mimics the chemical scent that the ants use to recognize their own brood. So the gullible ants carry the caterpillar into their nest, and don’t seem to notice when it proceeds to devour the very ant brood it has been mimicking.

Orchids are also wicked olfactory deceivers. They need to attract wasps, bees and other insects to spread their pollen. So some orchid species have evolved the shape and coloration of specific female insects — and also release chemicals that duplicate the come-hither perfume of the females they mimic. (It’s interspecies cross-dressing — and, wait, do I hear a Broadway musical?)

The duped males respond at first with clumsy groping and then quickly proceed to copulation, sometimes to the point of ejaculation. It gets more interesting: Some male wasps actually seem to prefer the scent of make-believe females. They will break away from a real female to have sex with a flower.

This effect of inducing others to drop everything and pay attention to me-me-me is apparently what we hope for with our own perfumes and colognes, at least to judge by the advertising. But scientists and perfumers seem to know remarkably little about which scent compounds — noxious or otherwise — produce particular effects, or why. We don’t seem to respond like those species in which a specific scent automatically elicits a fixed behavioral response, said Pamela Dalton, a scent researcher at the Monell Chemical Senses Center in Philadelphia.

Or at least we’re not aware if something like that is happening. A 2003 study at Monell found that scent samples from human males caused a neuroendocrine response in women, changing the length and timing of the menstrual cycle. Male scent also made the women less tense and more relaxed, at least when they didn’t know that what they were smelling was a man. (More predictably, a study this year reported that the scent of male, but not female, experimenters left lab rats feeling a stress level roughly equivalent to being restrained in a tube for 15 minutes.)

Ms. Dalton theorized that early perfumers might have adapted the sometimes unpleasant odors of other species as a way of taking on their power. Something like that certainly happens in the animal world.

For instance, some squirrels chew on the shed skins of rattlesnakes, their ancient enemies, then lick the smell onto their own bodies. Concentrating the scent around the tail may mask the strong odor of the anal glands and thus reduce the likelihood of detection. Or the squirrels may just be trying to trick rattlesnakes into thinking they have entered the territory of another snake. Shaking the tail or lifting the snake-scented hairs on their backs may be an effective way to disperse the warning scent.

Similarly, our beloved pet dogs are notorious for rolling in rotted fish, excrement, smelly seaweed or just about any other foul substance they can find.

The dog sniffer and scholar Stanley Coren argues that this dismaying behavior is about disguise: In the wild, canines are predators, and smelling like dogs, jackals or wolves would provide advance warning to their usual antelope prey. Perfuming themselves with antelope dung or carrion, on the other hand, might make it easier for them to sneak undetected within attacking distance.

Mr. Coren cannot help himself, though, from offering an alternative explanation with considerable appeal but “no scientific merit whatsoever.” Your whimsical, sensation-craving dog may roll in filth simply as “an expression of the same misbegotten sense of aesthetics that causes human beings to wear overly loud and colorful Hawaiian shirts.” Or maybe Axe cologne.

My own theory is a little different, and it has to do with the stinky behavior of spotted hyenas. They seem to roll in carrion and other horrible animal-based smells mainly because it wins them lots of curious sniffing and grooming from other hyenas. In effect, smelling that way makes them more popular. Noxious odors are a way of attracting attention, and perhaps they function the same way in our own perfumes and colognes.

Perfumers would no doubt vehemently argue otherwise. What a civet or skatole does is “nothing short of magic,” one of them writes. It transforms everything it touches “to produce a pleasant and singularly attractive scent.” But what if those scents actually linger there subliminally, unchanged, below our ability to be aware of what we are smelling?

A study in the journal Science early this year reported that humans can in theory distinguish a trillion different scents, and it’s hardly surprising to think that we could detect even trace amounts of the natural odors of mammalian bodies. In perfume, maybe that just wakes up our jaded nostrils and makes us pay attention to those gorgeous floral notes the perfumers like to go on about. Maybe, as Yeats suggested, fair really does need foul, and the baser elements in a perfume or cologne are essential to its erotic appeal.

In any case, it reminds us — reassuringly, I think — that we are animals. So by all means, lay on the perfume and cologne. Wear it in confidence, knowing that you and your dubiously anointed dog share one very special thing in common.