Can you smell time? Your dog can.
On a very basic level, so can you: When you crack the lid on that old quart of milk, tentatively sniff and—peeyouu!—promptly dump that foul stuff down the sink, you are, in effect, smelling time. Specifically, you can smell that far too much time has elapsed since that milk was fresh.
But a dog can smell time with a sophistication that puts our simple sniffers to shame. “Odors exist in time, and dogs perceive that,” explains cognitive scientist and canine researcher Alexandra Horowitz of Columbia University. “Dogs use smell to ‘tell time,’ in some sense, because a more recently laid odor smells stronger, and an older odor smells weaker.”
A dog’s nose is a notoriously sensitive piece of equipment. With up to 300 million olfactory receptors compared to our lousy 5 million, a dog can detect a single teaspoon of sugar dissolved into a million gallons of water, the equivalent of two Olympic-sized swimming pools. Unlike us, dogs are able to take in scent continuously, even as they exhale. What’s more, a dog’s nostrils are smaller than the distance between them, effectively giving dogs “stereo” sniffing power that carries subtle grades of information, including directionality.
Read full article at Strange Attractor
WANDERLUST 
Cool!