Cows have evolved a variety of adaptations that help them survive, including the ability to sweat, regulate body temperature and digest foliage that would be undigestible for many mammals. The modern cow's digestive system is sometimes said to be its most unique and important adaptation.
Cows spend much of their time chewing and digesting food. The entire digestive process can take 70-100 hours. This long process is the result of a set of adaptations that makes it possible for cows to eat a variety of foraged plants and leaves.
Cows have four-chambered stomachs that allow them to complete a repeated process of chewing and partially digesting tough and fibrous foliage. Cows also have adapted impressive processes to manage and regulate body temperature, from things like sweating and panting to adjusting behavior by seeking shady, cooler areas in hot weather. These adaptations have helped make cows hardy animals.