Does everyone smell different?
People really do seem to have a unique odour that marks them out.
There are many good reasons to believe that we all have our own unique smell. Dogs, for example as pets or police sniffers seem to be able to distinguish individuals by their smell. And the mother-baby bond is cemented by their own distinctive odours.
Now a large and systematic study led by Dustin Penn from the Konrad Lorenz Institute for Ethology in Vienna, Austria, has provided stronger support for the notion that your smell might distinguish you from others maybe even as much as your face.
The researchers further suggest that profiles of individual odours may also fall into two groups according to gender men more commonly have some smelly compounds, women more commonly others.
The researchers took samples of armpit sweat, urine and spit from 197 adults. Each subject was sampled five times over a ten-week collecting period. They extracted thousands of volatile chemicals from the samples the type of compound most likely to have an odour and identified them by chromatography and mass spectrometry.
The team found many more different volatile chemicals in sweat than in urine or saliva, it reports in Journal of the Royal Society Interface1. This could be because humans have a reason to be able to distinguish themselves by general body odour, more than by marking territory as many other animals do.
An individual's cocktail of odours changed all the time, but the researchers identified nearly 400 compounds that persisted in sweat samples taken at different times compounds that seem to be uninfluenced by what a person eats, for example. Comparing the presence and absence of these 400 compounds between any two given people seems to uniquely separate one from another, including people who lived together or were closely related.
But it isn't known just yet whether everyone on the planet has a 'smellprint' that marks them as uniquely as a fingerprint, says Penn. More data are required to determine for certain whether individual odour profiles will provide reliable biometric data.
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- Penn D., et al. J. R. Soc. Interface, doi:10.1098/rsif.2006.0182 (2006).