Animals can be classified based on their diet as herbivores, carnivores, or omnivores, or based on taxonomic grouping as mammals, birds, reptiles, amphibians or fishes. Depending on what they eat, animals are classified as herbivores if they eat plants, carnivores if they eat other animals, or omnivores if they eat both plants and other animals. Their taxonomic grouping depends on the class they belong to as mammals, birds, reptiles, amphibians or fishes.