If a dog leans in for an awkward sniff the moment a guest walks in the door, it isn't being rude by its own standards — it's doing exactly what its nose evolved to do. Smell Is a Dog's Primary Way of Reading the World Dogs rely on scent the way humans rely on sight. Estimates for a dog's scent receptors vary by breed and source, but most land somewhere between 100 million … [Read more...] about If Your Dog Keeps Sniffing Your Crotch, Here’s What’s Actually Going On