We humans do not have a very good sense of smell it must be said. Although we can smell things that are poisonous or otherwise harmful to us, the actual size of the receptors in one's nose are only about the size of a fingernail.
Dogs on the other hand are very well known for their keen sense of smell. They're employed at airports and other security venues to stop dangerous and contaminating items from entering through customs and things like drugs from passing on board.
My question then is this: If dogs have such a brilliant sense of smell, why then do they have this bizarre need to put their noses into poo?
Smell particles (for want of a better term) in the environment hang around after the person or item has left for quite some time. If I was to sit on the lounge and then sit at the kitchen table, a dog would be able to tell where I've been up to 6 hours later and it's this ability that's employed when tracking game and people once they've gone missing.
Why smell poo for, given that they can smell things well after they've gone?
I put it to you that dogs have far different interests than we do. I bet that if there was a bakery, then we'd want to stand as close to it or even inside the building if we could to experience the glorious smell of baking bread.
Poo tells dogs who else has been there, almost like the dog version of the newspaper. I suppose it's akin to people reading Hello! magazine.
Then I had another thought. If they have such an acute sense of smell, then how come it isn't damaged by sticking their noses into such a putrid smell source like poo.
I suspect that it has something to do with the tissue that the nose is composed of. In humans there are only three places in the human body that comprise erectile tissue: two I don't care to mention and the other is in the nose. This is most evidenced by our ability to flare our nostrils.
In dogs, this erectile tissue must be able to somehow close down the olfactory sense to the point that only a fraction of those smell particles hit the receptors.
It still doesn't look good though.