Philtrum Keeps Animal Noses Wet

The philtrum, the groove in the middle of your upper lip, exists in all mammals but serves a more functional role in many animals than in humans. In non-primates like dogs, it is narrower and helps channel saliva from the mouth to the nose through capillary action, keeping it moist. A wet nose improves the ability to trap scent particles, which enhances smell, showing that this small feature plays a key role in animal sensory function.

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