the science of sniffing: how dog’s noses support their wellbeing

1. Dogs Live Through Their Noses

For dogs, sniffing isn’t just a pastime - it’s how they interpret the world. With an estimated 125–300 million olfactory receptors (compared to just 5 million in humans) and a significant portion of their brain dedicated to scent processing, dogs are true scent specialists. They also use the vomeronasal organ (VNO) to detect pheromones and other social cues.

Their unique sniffing style - short, rapid inhalations maximises odour capture and helps them separate different scent layers, creating a rich sensory picture of their environment.

2. Their Nose Is a Thermal Sensor, Too

Dogs can detect more than odours. Research has shown that their rhinarium (the cold, moist surface of the nose) is sensitive to radiant heat. This allows dogs to sense the body heat of small mammals at distances of over a metre, even without seeing or hearing them. Brain imaging confirms that thermal cues activate specific areas of the canine brain, giving them a hunting advantage.

3. Sniffing and Welfare: Not Optional, It’s Essential

Sniffing is a species-typical behaviour fundamental to canine welfare. It provides mental stimulation, reduces stress, and allows dogs to process information about their surroundings. In shelters, olfactory enrichment (like scent trails or scented cloths) has been shown to reduce stress behaviours and promote calmness.

When dogs are prevented from sniffing—such as during rushed, highly controlled walks, they lose out on enrichment, leading to frustration, anxiety or boredom. Over time, this lack of sensory engagement can contribute to behavioural issues and reduced wellbeing.

4. Why Stopping Sniffing Hurts

Preventing sniffing is a form of sensory deprivation. Without opportunities to explore with their noses, dogs may experience:

• Reduced mental stimulation and learning opportunities

• Higher stress levels

• Frustration-based behaviours (pulling, barking, chewing)

• Missed opportunities for social communication with other dogs

Allowing sniffing, on the other hand, supports calmness, improves emotional balance and strengthens the bond between dog and guardian.

5. Practical Takeaways

• Slow down walks and give dogs time to explore.

• Use longer leads so they can investigate safely.

• Add scent enrichment at home (snuffle mats, scatter feeding, scent trails).

• Encourage social sniffing when safe, as it’s an important part of canine communication.

• Balance exercise with enrichment - a 20-minute sniffy walk can be more satisfying than an hour of physical exercise.

References

1. Bálint, A., Vásárhelyi, Z., Dóka, A., Miklósi, Á., & Andics, A. (2020). Dogs can sense weak thermal radiation. Scientific Reports, 10, 3736.

2. Kokocińska-Kusiak, A., Woszczyło, M., Zybala, M., Maciocha, J., & Barłowska, K. (2021). Canine Olfaction: Physiology, Behavior, and Possibilities for Practical Application. Animals, 11(9), 2463.

3. Berg, P., & colleagues. (2024). Olfaction in canine cognitive and emotional processes. Neuroscience & Biobehavioral Reviews, 157, 105460.

4. Binks, J., Taylor, S., Wills, A. P., & Montrose, V. T. (2018). The behavioural effects of olfactory stimulation on dogs at a rescue shelter. Applied Animal Behaviour Science, 202, 69–76.

5. Waller, B. M., Peirce, K., Caeiro, C., Scheider, L., Burrows, A. M., McCune, S., & Kaminski, J. (2013). Paedomorphic facial expressions in domestic dogs: Development and validation of the DogFACS coding system. Behavioural Processes, 96, 1–10.

6. Horowitz, A. (2016). Being a Dog: Following the Dog Into a World of Smell. Scribner.