Wet nose for better smell

Source: newscientist.com
Dogs owe their keen nose (for food to cocaine and money) to their nasal membrane. This membrane preselects the scent, which enables the animals to distinguish a lot more scents.
It was already known that the noses of dogs contained more neurons and scent receptors than those of humans. A team of scientists of Pennsylvania State University now discovered that a complex maze of membranes covered in mucus ‘preselects’ the scent, making it easier for the brain to distinguish between scents.
Scent molecules first have to penetrate the mucus in order to reach the scent receptors. Some molecules are easier absorbed by the mucus than other molecules. Different scents are recognised in the nasal cavity at different moments.
The scientists used MRI scans of dog noses to model the route the air travels through the nasal cavity.

Up till now, research with regard to scent was aimed primarily at the way that scent receptors recognise different kinds of molecules. The new research shows that the sorting of the different components of scent before they reach the scent receptors is just as important.