You are ready to get moving. Your dog is still inspecting the same patch of grass.

It might look like a delay, but sniffing is one of the main ways dogs explore their surroundings. And their noses work in a surprisingly clever way. 

Breathing out helps them smell more

Those rapid little sniffs do more than pull air in. As a dog breathes out, air travels downward and outward from its nostrils, helping draw nearby scent-bearing air toward the nose for the next breath.

Researchers copied this action using a 3D-printed dog nose. When they fitted a commercial vapour detector with a dog-inspired attachment, its odour-detection ability improved in their tests.

The research, published in 2016, shows that part of a dog’s remarkable ability comes from how it moves the air around its nose.

Three more things their noses can do

• Pick up the smell of human stress. In a 2022 study, four trained dogs distinguished breath and sweat samples collected before and after a stressful task with almost 94% accuracy across 720 trials. They did not need to see or hear the people. 

• Recognise a familiar person through scent alone. Emory researchers found that a brain area associated with reward responded most strongly to a familiar human’s scent, compared with the other human and dog smells tested. That person was not present during the scan

• Notice emotional clues in another dog’s smell. A 2026 study found that dogs distinguished play-associated scent from samples collected after rest or stress. In a follow-up test, stress-associated scent prompted dogs to stay nearer their owners. The samples came from one donor dog, so the findings need broader testing. 

Give that nose something to do

On your next walk, allow a few unhurried stops at safe spots. Where practical, let your dog choose a direction or explore a different route.

Cornell’s veterinary guidance recommends these simple ways to make walks more rewarding, including for older dogs who cannot manage long distances. 

At home, try a “find it” game. Let your dog watch you place a few pieces of their usual food in easy-to-reach spots, then let them search. Gradually make it harder, supervise and use part of their daily food allowance.

• More ideas: Cornell’s guide to activities for your dog.
• See how sniffing works: NIST’s dog-nose research and videos.

The Bottom Line

A walk gives your dog something to investigate and somewhere to exercise. Next time that nose finds an interesting spot, give it a moment if it is safe. There is plenty happening that you cannot smell.