Silent language of scents | Sunday Observer

Silent language of scents

30 August, 2020

Scientists have found a silent and secret language of scents which affect our behaviour. It is supposed to be the oldest language in the world. It has been named ‘pheromones’ derived from the Greek word ‘pherein’ meaning ‘carry on’ and ‘horman’ meaning ‘to excite or stimulate.’ The scents are common to every living being.

According to scientists, most living beings still use the sense of smell to communicate. Why does your pet cat rub her cheeks against your leg? She does so because her scent glands are located at the base of her whiskers. By doing that rubbing the cat silently says, “He belongs to me.” Likewise, you may have seen dogs urinating around trees and lamp posts. They do so to mark their territory. Not only dogs, even wolves scent mark their boundaries. Any dog or wolf trying to enter the marked territory will have to think twice before doing so. Female rats also leave their scent mark to regulate the mating cycle.

In addition to marking the territory, pheromones directly affect reproduction. The female gypsy moth sends out a scent signal in spring to indicate that she is ready for mating. Scientists have isolated the chemical to distract males from pursuing males and they are lured into traps. This is another scientific war against insects which can destroy paddy fields and harvest.

Ant colony

Long before man used pheromones to destroy insects, ants had used it in their colonies. When an ant colony comes under attack, the ants release a chemical similar to pheromones compelling the invaders to beat a retreat. Scientists have found that pheromones can be used to instil fear in the attacker. Unlike animals, humans are poorly equipped to live by smell. While a German shepherd dog has 320 million cells in its nose the number of cells in the human nose is relatively less. The salmon uses its sensitive nose to cross rivers and mighty oceans, but humans are poorly equipped to use their noses. Instead they use their eyes and ears although their noses are quite sensitive. For instance, the odour of a dead animal can be unbearable. Natural gas has no odour but scientists have added a foul odour to it to warn users of gas leaks. Even at home when you smell something foul, you use your nostrils to detect the source.

Sensitivities to odours can vary widely among individuals. When I was working in a state media organisation, one day the staff found it very difficult to work because of a foul smell. All of us tried to locate the source with our noses but we failed. Then we informed the maintenance department. They sent a man who detected the source quite easily and removed a dead mouse from a nook. We heaved a sigh of relief!

Different odours

Scientists say most of us can recognise at least 4,000 different odours, but there are some people who can recognise 10,000 distinct odours. On the other hand, a woman’s nose is more sensitive than that of a man. Whatever that may be, the perception of odours involves pheromones and hormone.

We still do not know how the sense of smell works. According to one theory, our scent cells respond to the shape of molecules. In fact, there may be only a few dozen scent receptor shapes in addition to primary colours. Scientists can combine primary colours to produce unusual scents. According to another theory, our noses can detect vibrations just like eyes and ears. Scientists are still debating the issue.

The olfactory cells of the nose are directly connected to the limbic system of the brain. It regulates our primary drives relating to sex, hunger, and thirst. Consisting of a series of doughnut-shaped structures that include the amygdala, hippocampus, and fornix, the limbic system borders the top of the central core and has connections with the cerebral cortex. In simple terms, the limbic system controls our eating, aggression and reproduction.

Human body

The human body emits certain chemicals which function as pheromones in other species. For instance, when we perspire, we give off a complex scent called ‘androsterone.’ Even some animals such as wild boars and pigs emit this substance. For them it is an odour signal of aggression in male boars and receptivity to mating in sows. According to scientists, most men cannot detect any odour in androsterone but women tend to smell it most readily when they are midway through their monthly cycle.

The results of ‘sniff tests’ show women have a better sense of smell than men. Most people have the ability to distinguish males from females on the basis of smell alone. People can also distinguish happy from sad emotions by sniffing underarm smells. Women are able to identify their babies solely on the basis of smell.

Most of us are unaware that scents are used to lend an air to stationery and greeting cards. This gives an illusion of freshness to them. Today this has extended to fabric softeners, dishwashing liquids, and washing powders. Apart from using scents in paints and medicines, even reconditioned cars are given a spray to give them a ‘new car’ smell. In the modern world, we are continuously influenced by odours but we have the freedom to ignore them if necessary.


It is interesting to note that in ancient times doctors diagnosed illnesses by the smell of their patients. Typhoid fever was said to produce a smell like hot bread, measles like freshly-plucked feathers, insanity like the scent of mice or deer, plague like honey, yellow fever a butcher-shop odour. The art of odour diagnosis has not been abandoned. Medical research shows that if the breath of a patient has the peculiar smell of acetone, diabetes is the probable cause. If the smell is of ammonia, his kidneys are probably the culprit.

Our senses of smell and taste are inextricably linked. If you smell something savoury, your mouth will begin to water. Smell something rotten, you will get a bad taste in your mouth. For a dog or cat, there is a wealth of things to be smelt and tasted every day. But such a world of sensation is unknown to humans. They find good smells amazingly therapeutic. When you smell forest ferns, roasting coffee beans, freshly-baked bread, you feel happy. Although smell is the most evocative of senses, we do not pay much attention to our noses.

Scientists believe that we can make up the ancient sense of smell and put it to work because we transmit millions of messages that only the nose knows. We do not know whether all such smells would lock into our hormones. However, if we pay some extra attention to them, they will provide us with amazing information about ourselves and others.

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