The smell that wafts off a dog after they go for a swim or bath. It's not particularly pleasant.
A recent video from the American Chemical Society explains just how the chemistry behind this unique smell works.
First a primer on smell, from Wired's Nick Stockton:
When you inhale, microscopic airborne molecules alight upon specialized cells - called olfactory sensory neurons - deep in your nasal cavity. These cells translate the chemical signature from the molecules into an electrical signal, which gets sent along to your brain. There, it triggers the circuits that help you put a label to the smell: Bacon! New Book! Wet dog!
As for where those smells come from? Well, it turns out that it's not really the dog itself that smells, but excretions from the microorganisms that live in a dog's fur. These yeast and& bacteria poops don't smell when they are dry but as soon as water hits them they start breaking apart and creating a fog of musk around your dog, according to Wired.
Getting wet makes a dog smell worse because those compounds are better able to escape from the furry confines of a dog's coat. As it evaporates, the water in the dogs coat lifts those molecules up and out of the fur, and all the way up to our noses.
This could be even worse if it's humid outside. The more moisture air holds, the more it can transfer smells to your nose.
While wet dog smell might offend some human olfactory senses, dogs probably experience it differently. Dogs have 220 million olfactory receptors give them a sense of smell stronger than anything we humans can experience. Even the mucus on their nose helps them efficiently process smells.
All those smelling powers that a dog possesses they usually direct towards sniffing out disgusting smells. It turns out dogs are attracted to smells produced by molecules that scientists describe as causing the 'dead body smell.'
Watch the whole video, from the American Chemical Society's YouTube channel, for more canine chemistry: