In the canine world, sniffing is a form of social interaction. It functions like a way of “reading” information about another being, similar to how humans use conversation to learn about each other.
Dogs may pick up on emotional states such as stress, excitement, or calmness, and in some cases, trained dogs can even detect medical changes in humans.
Puppies and younger dogs tend to rely on sniffing even more heavily because they are still learning social boundaries and environmental cues.