Love smells

nothing
Looking for love in all the wrong places Starting a strange journey...
Watch a snake slithering along, forked tongue gliding in and out, following unseen signals in its search for a tasty rodent. Watch a dog marking territory by "painting" a hydrant. Watch insects mate. Or stand back a bit and observe a tusk-clanging, horn-honking battle of bull elephants.
In each of these everyday animal events, you're seeing the effects of a subtle but powerful group of chemical messengers called pheromones. Animals use pheromones for discussions with members of their species about the big stuff: topics like food, domination, territory and sex. And pheromones, it turns out, can act at vanishingly small concentrations, below what the sense of smell can detect. Moths, for example, can detect pheromones from other moths for several miles downwind.

snake
Pheromones and odors have a lot in common: both are airborne chemicals detected by specialized nerve cells in the nose. But pheromones are generally defined as chemical signals between animals of one species.
The human snout may have two separate structures for detecting chemicals in the air. The olfactory epithelium samples a broader range of substances, but some claim the vomeronasal organ (VNO) has more ancient roles in fight, flight and sex.
If odors could talk...
Keeping in mind the fact that human pheromones may or may not actually exist, let's keep looking at this animal communication system.

nose diagram Odors are detected by the olfactory epithelium, a group of nerve cells located deep inside the snout. Pheromones are detected by those cells, or by a tiny group of nerve cells in the vomeronasal organ, or VNO. In people, a tiny pit located on the divider between the nostrils could be the long-sought VNO.

Odors seem more various than pheromones. The rat seems to have about 30 types of molecular receptor in its VNO -- meaning the organ can distinguish at least that many chemicals. But it may have 10 times as many receptor types in its olfactory epithelium, where the sense of smell starts.

Odors are largely a learned response -- we learn to associate garlic with spaghetti dinner, or lime with a margarita. In contrast, pheromones that affect physiology (say, hormonal balance) called "primer pheromones," seem hard-wired into animal brains. In contrast, pheromones that affect behavior, such as those that stimulate or inhibit aggression, do not produce an automatic response -- the animal gets the signal and then, depending on environment and other factors, may or may not respond to it by changing behavior.

There seems to be considerable gender-specificity to many pheromones -- males do not respond to compounds that affect females, and vice versa.

We saved the weirdest for last: The human sense of smell operates on a conscious level. We know we're smelling burnt rubber when a muscle car leaves a stoplight. We know we're smelling coffee when we wake up and smell the coffee. But human pheromones -- if they exist -- may occur on the unconscious level. Translated: We wouldn't know what hit us. Creepy.

nothing After reading that list, please remember that there's still considerable question about whether people actually respond to pheromones, but we'll talk with the doubters later.
Enough speculation. Don't you have any facts?

nothing There are 1 2 3 4 5 6 7 8 9 10 documents.
Glossary | Bibliography | Credits | Search

	Odors are detected by the olfactory epithelium, a group of nerve cells located deep inside the snout. Pheromones are detected by those cells, or by a tiny group of nerve cells in the vomeronasal organ, or VNO. In people, a tiny pit located on the divider between the nostrils could be the long-sought VNO.
	Odors seem more various than pheromones. The rat seems to have about 30 types of molecular receptor in its VNO -- meaning the organ can distinguish at least that many chemicals. But it may have 10 times as many receptor types in its olfactory epithelium, where the sense of smell starts.
	Odors are largely a learned response -- we learn to associate garlic with spaghetti dinner, or lime with a margarita. In contrast, pheromones that affect physiology (say, hormonal balance) called "primer pheromones," seem hard-wired into animal brains. In contrast, pheromones that affect behavior, such as those that stimulate or inhibit aggression, do not produce an automatic response -- the animal gets the signal and then, depending on environment and other factors, may or may not respond to it by changing behavior.
	There seems to be considerable gender-specificity to many pheromones -- males do not respond to compounds that affect females, and vice versa.
	We saved the weirdest for last: The human sense of smell operates on a conscious level. We know we're smelling burnt rubber when a muscle car leaves a stoplight. We know we're smelling coffee when we wake up and smell the coffee. But human pheromones -- if they exist -- may occur on the unconscious level. Translated: We wouldn't know what hit us. Creepy.
	After reading that list, please remember that there's still considerable question about whether people actually respond to pheromones, but we'll talk with the doubters later. Enough speculation. Don't you have any facts?