Stomach

Gastric acid in the stomach reaches a pH of 1.5 to 3.5 — acidic enough to dissolve zinc and corrode certain metals. Yet the stomach doesn't digest itself because mucus-secreting cells continuously coat the stomach wall with a protective bicarbonate-rich mucus layer. This protection is temporary: the stomach completely replaces its inner lining every 3–4 days. If this renewal failed, gastric ulcers would quickly develop, as occurs in H. pylori infections that disrupt the mucus barrier.

Like cows, giraffes have a specialized digestive system that allows them to efficiently process tough plant material. They chew their cud, regurgitating partially digested food to chew it again, maximizing nutrient extraction.