Herbivorous dinosaurs were plant-eating reptiles that roamed the Earth during the Mesozoic Era. They had various adaptations to help them consume and digest vegetation, such as flat teeth for grinding leaves and long necks for reaching high branches. Some well-known examples include the Brachiosaurus and Triceratops. These dinosaurs varied greatly in size and shape, from small, agile species to massive giants. Many lived in herds, which provided protection from predators. Herbivorous dinosaurs played a crucial role in their ecosystems by helping to shape plant life and serving as a food source for carnivorous dinosaurs like the Tyrannosaurus rex.