A dog’s nose is anywhere between 10,000 to 100,000 times more sensitive than ours, and smelling each others’ butts is just their way of getting to know each other.
That’s how dogs ask about another dog’s diet, gender, and emotional state.
Researchers studying the anal secretions of dogs discovered that, next to their butt, canines have pouches called anal sacs. These hold the glands that secrete chemicals they use to get to know each other.
Amines and acids are the primary compounds involved, and genetics and the state of their immune system can influence the aroma as well.