AP BIOLOGY

Detailed explanation-1: -1. They Can’t Breathe Through the Mouth! Horses, unlike many animals, only breathe through the nose and cannot breathe through the mouth.

Detailed explanation-2: -The horse is an obligate nasal breather: it can only breathe through its nostrils, unlike people who can breathe through their nose or mouth or nose and mouth simultaneously. This is because a structure called the soft palate completely separates the upper part of the airway above the mouth from the mouth itself.

Detailed explanation-3: -Horses can’t breathe through their mouth. Strange, right? Referred to as an “obligate nose breather", a horse’s air intake is strictly confined to their nostrils and nasal passages.

Detailed explanation-4: -The epiglottis, therefore, lies on top of the soft palate, making the horse an obligate nasal breather. That is, air cannot enter the mouth to reach the trachea because the soft palate blocks the airflow. Thus, the horse is the epitome of the proverb, “The nose is for breathing, the mouth is for eating.”