Why are dogs noses wet?

Special glands inside the nostrils secrete a thin layer of mucus that absorbs odour chemicals from the air, which the dog then processes with up to 300 million olfactory receptors, compared with about 6 million in humans. Dogs frequently lick their noses, both to keep the surface moist and to transfer scent particles to an organ in the roof of the mouth that detects chemical signals. The moisture may also help a little with cooling, although dogs mainly lose heat by panting and sweat through their paw pads. A 2020 study found that the cool tip of a dog nose can even sense faint heat radiating from warm objects. Contrary to popular belief, a warm or dry nose on its own is not a reliable sign that a dog is ill.