Texas A&M University (TAMU) ANSC108 General Animal Science Laboratory Final Practice Exam

Horses, as non-ruminant herbivores, have a unique digestive system that is adapted to their diet, consisting primarily of forage. One significant limitation of this system is that horses cannot vomit. This inability is due to their specialized anatomy, particularly the structure of the esophagus and the lower esophageal sphincter, which prevents the reversal of food from the stomach back into the esophagus.

Most mammals, however, can vomit as a protective mechanism to clear the stomach of potentially harmful substances or when they are sick. This function allows them to respond to toxins or irritants in their digestive tract more effectively than horses can. Therefore, the ability to vomit is a critical function that distinguishes most mammals from horses and highlights the adaptation of their digestive processes to their herbivorous lifestyle.

The other options relate to different aspects of digestion and nutrient absorption that may not vary significantly between mammals, or they may not accurately reflect the unique physiological limitations of horses compared to other mammals.