Why do herbivores such as cows and horses have broad flat cheek teeth?

Herbivores such as cows and horses possess broad, flat cheek teeth (premolars and molars) as a functional adaptation for their specialized diet. Unlike animal cells, plant cells are encased in rigid cellulose walls that must be broken down to expose the nutrients inside for digestive enzymes. Because few animals can digest cellulose directly, thorough mastication is essential for herbivores to process their food effectively.1

These broad, flat surfaces, often featuring complex ridges and cusps, provide an expansive grinding area that allows these animals to crush and pulverize tough plant material. To further enhance this grinding efficiency, many herbivores exhibit "molarization," where premolars expand and flatten to resemble molars. Additionally, many grazing species have evolved high-crowned teeth, known as hypsodont teeth, which are reinforced with secondary cement to resist the heavy wear caused by a diet of abrasive plant matter. This specialized dentition ensures that herbivores can efficiently extract energy from their fibrous, plant-based diet.2134