Herbivores eat plants. Cattle, deer, rabbits, caterpillars, and many birds fall into this category. Their bodies reflect their diet. Flat teeth for grinding plant fibers. Long digestive tracts for breaking down cellulose. Some, like cows and sheep, have multi-chambered stomachs that host bacteria capable of digesting tough plant material. Others, like rabbits, eat their own droppings to extract more nutrients on the second pass.

Herbivores shape ecosystems. Grazing herds keep grasslands open by preventing shrubs and trees from taking over. Browsing animals like deer and elephants prune vegetation and create gaps that let light reach the forest floor. Without herbivores, many landscapes would change dramatically. Removing large grazers from the Serengeti would allow woody plants to spread and reduce habitat for the species that depend on open grass. Herbivores are also food for carnivores. Their populations rise and fall with the quality of the plants they eat and the pressure from predators.

Types of herbivores

• Grazers: eat grasses and low vegetation.
• Browsers: eat leaves, twigs, and shrubs.
• Frugivores: eat fruit.
• Nectarivores: eat nectar from flowers.

Herbivores are not passive. They influence which plants survive, where they grow, and how forests and grasslands are structured.