In areas where the air is very dry, such as deserts, a larger mucous area is required to moisten inspired air, and this necessitates a longer and narrower nose ( <a href="http://www.hallofmaat.com/modules.php?name=Articles&file=article&sid=73#Molnar%201983">http://www.hallofmaat.com/modules.php?name=Articles&file=article&sid=73#Molnar%201983</a> - Molnar 1983 :71-73).