Dogs detect scents from a kilometer away, yet still rush to press their wet noses against a human’s hands, clothes, and bags.
“If some aroma interests her, she just starts breathing through her nose a little more often to increase the concentration of the right substances,” Muretov told NGS.RU.
An animal’s olfactory epithelium covers a far greater surface area than a human’s, and the corresponding brain regions are developed incomparably stronger. Close-range sniffing likely engages the vomeronasal organ to pick up chemical signals and pheromones that do not easily evaporate from fabric or skin.
A dog instantly registers a person’s emotional state by detecting changes in volatile substances released through breath and sweat during acute stress. In laboratory trials cited by NGS.RU, dogs correctly identified stress sweat samples in roughly 94 percent of trials.
This scent detection directly alters canine behavior, causing animals to grow more cautious or experience elevated heart rates when exposed to fearful human odors. Conversely, relaxed scents encourage positive interaction.
Beyond emotions, dogs can detect certain infections and cancers. Trained household dogs participating in trials regarding Parkinson’s disease identified sebum samples from patients with roughly 89 percent accuracy while correctly rejecting about 87 percent of healthy samples.
“Dogs-detectors are trained for a long time on specially prepared samples, and a domestic pet may be interested in a cream, ointment, someone else’s cat’s smell, or spilled sauce,” Muretov told NGS.RU, adding that owners should visit a physician rather than rely on pet behavior for medical diagnoses.
Olfactory capabilities can decline due to inflammation, overheating, dehydration, aging, or specific medications such as certain antibiotics and steroid hormones. Owners often miss these changes unless a dog stops searching for hidden treats or sniffing scent marks on walks.
When nasal discharge accompanies this loss of scent, it typically indicates an inflammation that requires veterinary care. Letting dogs explore scents during walks provides mental calm, but owners must manage public interactions carefully.
“Therefore, in crowded places, it is better to keep the dog on a short leash and teach it to move away from a person on command,” Muretov told NGS.RU.
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