An Explanation of Why Dogs Sniff Each Other’s Rear Ends

“Why Do Dogs Smell Each Other’s Butts” by Reactions breaks down the compulsion of canines to stick their noses in each other’s rumps. The site enlists professor George Preti of the Monell Chemical Senses Center to break down the surprising complexities of the seemingly odd behavior.

When a dog smells another dog’s butt, it’s actually collecting a bunch of information about the other dog: its diet, its gender, its emotional state and and so on. Think of it kind of as speaking with chemicals.