Mouth breathing is only really required when we need more air during exercise or respiratory distress, or when the nose is blocked. Thanks to the nasal cycle, air flows into the nostrils at different speeds and so each nostril handles odors differently. Two nostrils improve our ability to locate smellThe distance between our two nostrils is not as large as the distance between the eyes or ears. Two nostrils might give us an advantage against coldsTwo nostrils could even bring other benefits besides breathing and smell: They may help us fight viral infections. So next time you take a deep breath or smell a delicious pie, don’t take your two nostrils for granted.