On the fifth day of the fifth month of 1921, Coco Chanel changed the scent of the world. She released Chanel No. 5 as her final vaudeville act—her only child. The perfume would grow to be “le monstre" of the perfume industry, a $300-per-ounce, elegant mist still anchoring the multibillion-dollar Chanel empire. It succeeded where others had never tried by combining the cheap, musky scent of the courtesan demi-mondaines—the “women of the half-world,” as Coco herself was—with the light, single florals reserved for the upper class of Parisian women. Needing a musky base note, Coco resorted to an old perfumer’s trick: scrapings of sexual pheromones from the perianal gland of the Abyssinian civet cat.
Fast-forward to 1998. French chemists discovered something unexpected in a 1995 sauvignon blanc from Bordeaux: 3-mercapto-3-methylbutan-1-ol, a grape breakdown product that doubles as a fragrant pheromone in cat pee. We now know this is common to sauvignon blanc, and not always unwelcome among wine critics: “Compare [cat pee] to an off-note that adds complexity to a piece of music.” One New Zealand winery even named a bottle after the scent—“Cat’s Pee on a Gooseberry Bush.”
Why is it that the elite French perfumers (known as “noses”) and sommeliers (“upturned noses”) of the world spend so much of their time inhaling cat effluvia from expensive glass bottles? A guess: It may have to do with a mind-control parasite called Toxoplasma gondii. The tiny protozoan may be getting into our brains and tricking us into liking cats—not to mention certain perfumes and wines.
In a recent study, Czech scientists gave men and women towels scented with the urine of various animals—horses, lions, hyenas, cats, dogs—which they rated for “pleasantness.” Turns out, men who tested positive for Toxo found the smell of cat urine more pleasant than men without Toxo. For Toxo researchers like me, this was a shock but not entirely surprising. Why? Toxo does approximately the same thing to rats.
Toxo reproduces only in a cat’s stomach and needs an intermediate host to taxi from one cat to the next. Enter le rat. Toxo infects the rat brain and scrambles neurons to make the rat less afraid of cat urine. How? The neural circuitry for fear is right next to the neural circuitry for sexual attraction in male rats, and it seems Toxo can hijack the sexual attraction circuit to respond to cat urine. A less-afraid (and maybe even a little turned-on) rat is thus a likelier-to-be-eaten rat, allowing Toxo to settle in the new feline host and start the lifecycle anew.
Sometimes, though, Toxo ends up in a human’s brain (an evolutionary dead end for the parasite, unless you are Val Kilmer), courtesy of forgetting to wash one’s hands after cleaning cat litter—the parasite is in cat feces—or eating undercooked meat with Toxo in it—livestock often stomp around on beds of fertilizer made from, yes, cat feces. Worldwide, 1 billion to 2 billion people have the tiny Toxo parasite in their brains.
Once you play host to Toxo, you have it for life. But unlike most anything else that finds a way into your brain, it’s basically harmless as long as your immune system is working and you aren’t pregnant. It’s possible that Toxo is doing something to the host human brain—we just don’t yet know what.
Now, maybe the men with Toxo from the Czech study have pet cats at home (making them more likely to pick up Toxo) and the cat pee evokes Elysian fondness for their Fluffypuss. In this case, Toxo does absolutely nothing but is still correlated with preferring the smell of cat urine. Or maybe these men with Toxo romantically incline to cat-ladies—women with Toxo might be more promiscuous, after all.