Scientists have confirmed that dogs can sense human stress by smell and do so more accurately than humans. This is reported by Animal Cognition.
A study by the University of Naples Federico II showed that trained dogs distinguished samples collected in a state of calm and stress with an accuracy of 93.75 percent. This was made possible by changes in volatile organic compounds in exhaled air and sweat that occur with increased heart rate and blood pressure. Dogs responded to these signals even in laboratory conditions, proving that they rely on physiological rather than behavioral cues.
The high sensitivity of a dog's sense of smell is explained by anatomy: their olfactory bulb occupies 0.31 percent of the brain's volume — 31 times more than in humans. Many breeds have over 220 million olfactory receptors, allowing them to detect minimal chemical changes. This mechanism complements visual and auditory signals, forming a complete picture of a person's emotional state for the animal.
A smell once associated with anxiety can remain in a dog's memory for a long time and trigger alertness upon re-encounter. Scientists note that such reactions are not manifestations of aggression but responses to a chemical signal. Fortunately, they can be modified through positive reinforcement.
