Human Pheromone Reviews
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How Pheromones Work - Part 2
This signaling system is particularly important to animals that are inexperienced sexually. Experiments have shown that the VNOs play a key role in triggering sexual behavior in naive targets.
A virgin male hamster or mouse whose vomeronasal organs are removed generally will not mate with a receptive female, they found, even if the male's main olfactory nerves are undamaged. Apparently, the VNOs are needed to start certain chains of behavior that are already programmed in the brain. Although only preliminary tests have been conducted, it is felt that this holds true for humans as well. This is why the smells produced by a horny partner is so arousing.
Do human beings have VNOs? In the early 1800s, L. Jacobson, a Danish physician, detected likely structures in a patient's nose, but he assumed they were non-sensory organs. Others thought that although VNOs exist in human embryos, they disappear during development or remain "vestigial"—imperfectly developed.
Recently, researchers have come to a different conclusion. Both VNOs and vomeronasal pits—tiny openings to the VNO in the nasal septum—have been found in nearly all patients examined by Bruce Jafek, an otolaryngologist at the University of Colorado at Denver and David Moran.
Just what do the VNOs of humans—respond to? Probably pheromones, a kind of chemical signal originally studied in insects.
The first pheromone ever identified (in 1956) was a powerful sex attractant for silkworm moths. A team of German researchers worked 20 years to isolate it. After removing certain glands at the tip of the abdomen of 500,000 female moths, they extracted a curious compound. The minutest amount of it made male moths beat their wings madly in a "flutter dance." This clear sign that the males had sensed the attractant enabled the scientists to purify the pheromone. Step by step, they removed extraneous matter and sharply reduced the amount of attractant needed to provoke the flutter dance.
When at last they obtained a chemically pure pheromone, they named it "bombykol" for the silkworm moth, "Bombyx mori" from which it was extracted. It signaled, "come to me!" from great distances. "It has been soberly calculated that if a single female moth were to release all the bombykol in her sac in a single spray, all at once, she could theoretically attract a trillion males in the instant," wrote Lewis Thomas in The Lives of a Cell.