According to Encyclopædia Britannica, a zebra spends a significant portion of its day eating limitless amounts of grass in order to accommodate its digestive system, which is less efficient than that of ruminants. Grazing exposes the zebra to predation, but it can survive eating low-quality grasses during times of drought.
Symbiotic bacteria within the zebra's cecum break down cellulose so that various grasses and forage can be digested. The zebra's digestive system is not adept at extracting protein from plant matter, although the speed in which it digests allows the zebra to eat a greater quantity than ruminants. Forage is usually too low in protein and too high in fiber for ruminants, while the zebra is able to subsist on it.