Herbivorous animals are vegetarians. They only eat plants.
Herbivores can be very picky eaters. Scientists group these creatures by the parts of plants the herbivore eats.
Frugivores only eat fruit. Folivorous birds feed on leaves. Nectivorous bats suck on nectar. Granivorous insects munch on seeds whereas polynivorous ones prefer pollen.
When the weather changes, however, herbivores often have to alter their diets to feed on whatever plant food is in season.
The teeth of herbivores have adapted to chew the tough fibers of plants. Their big molars grind up seeds and twigs. Special stomach chambers in some herbivores, such as cows and moose, are called rumen. The rumen contains microorganisms that break down the cellulose in grass so that the animal can collect as much energy as possible from the food.