The main diet of herbivorous animals consists primarily of plant material. This includes leaves, fruits, seeds, and stems from a variety of vegetation. Herbivores have specialized digestive systems that enable them to break down tough plant fibers, such as cellulose, through fermentation in their stomachs or through the action of bacteria in their intestines. Common examples of herbivorous animals include cows, horses, elephants, and many species of birds. Their role in ecosystems is vital, as they help in the growth and spread of plants and serve as food for carnivorous animals, maintaining the balance in food chains.