Why herbivores eat plants

The tapir spreads out its toes when it walks on soft ground. The South American tapir has a short, bristly mane, which provides protection if a jaguar bites its neck. Tapirs have a streamlined shape, which allows them to move more easily through dense undergrowth. Some animals specialize in eating one kind of plant, while others consume a range of different vegetation.

Toggle text. Carnivores are animals that eat only meat. Omnivores are animals that eat both plants and meat. The size of an animal does not determine what it eats. Some of the biggest animals eat only plants, and very tiny animals can be carnivores.

Some animals eat only plants, making them herbivores. Often, herbivores concentrate their munching on just the fruits or seeds of plants, ignoring stems, leaves, and roots.

Herbivores have special digestive tracts that are designed to handle different types of plants they might eat. Herbivores usually have big front teeth, called incisors. These teeth are used to grasp and cut plants. Herbivores also have molars in the back, which they use to grind up the plants in their mouths. Herbivores are often very large animals, such as cows, deer, and elk. As you might imagine, it takes a lot of food to give a large herbivore the energy it needs.

That is why herbivores may spend a large part of their day eating. Herbivores can also be medium-sized animals such as sheep or goats. Examples of small herbivores include squirrels and chipmunks.

Producers, who make their own food using photosynthesis or chemosynthesis, make up the bottom of the trophic pyramid. Primary consumers, mostly herbivores, exist at the next level, and secondary and tertiary consumers, omnivores and carnivores, follow. At the top of the system are the apex predators: animals who have no predators other than humans.

Help your class explore food chains and webs with these resources. A biotic factor is a living organism that shapes its environment. In a freshwater ecosystem, examples might include aquatic plants, fish, amphibians, and algae. Biotic and abiotic factors work together to create a unique ecosystem.

Learn more about biotic factors with this curated resource collection. The theory of natural selection was explored by 19th-century naturalist Charles Darwin.

Natural selection explains how genetic traits of a species may change over time. This may lead to speciation, the formation of a distinct new species. Select from these resources to teach your classroom about this subfield of evolutionary biology.

An herbivore is an organism that eats mainly plants and other producers. An omnivore is an organism that regularly consumes a variety of material, including plants, animals, algae, and fungi. They range in size from tiny insects like ants to large creatures—like people. A scavenger is an organism that consumes mostly decaying biomass, such as meat or rotting plant matter. Join our community of educators and receive the latest information on National Geographic's resources for you and your students.

Skip to content. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. Gorillas are a specialized type of herbivore called a folivore. Photograph by Chadwic Gifford, MyShot. African wild dog. Asian long-horned beetle. Also called puma, mountain lion, and panther. Also called a food cycle. Media Credits The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.

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Related Resources. Energy Flow Through an Ecosystem. View Collection. Food Chains and Webs. Biotic Factors. Natural Selection. View Article. View More Resources. They include: avoiding tough plant tissue by eating plant fluids. For example, sap-sucking bugs have a tube-like mouthpart called a rostrum, which they use to pierce the tough tissue and suck out the internal juices of the plant.

Many herbivores feed on nectar and have mouthparts for lapping, sponging or sucking. Nectar feeding specialists include insects such as butterflies, moths, bees, flies, wasps and beetles, and vertebrates such as lorikeets and honey possums. For example, miners are insect larvae that eat between plant cell layers.

A leaf miner may eat the entire leaf, leaving only the outer protective layers and the veins. Mining activity appears on the plant as tunnels, blotches or blisters. Common miners are the larvae of some flies, wasps, moths and sawflies. For example, leaf chewers have mouthparts that allow them to slice through leaves.

The most prolific chewers are the beetles and the larvae of moths and butterflies. Other important groups that feed directly on leaves are the grasshoppers, locusts, katydids, sawflies and stick-insects.

Some groups such as leaf-cutter bees, ants, termites and wasps collect leaf fragments to construct their nests or feed their young. For example, some insects have formed alliances with bacteria or fungi that are capable of breaking down complex chemicals, like the Ambrosia Beetles that distribute special fungi that liquefy woody material, which the beetle eats.

Plants defend against herbivores using complex chemicals Plants produce many chemicals for defence against herbivores. These include: detoxifying plant defence chemicals. For example, caterpillars and sawflies that feed on Eucalypts are capable of breaking down some of the chemical defences. Many Australian mammals, most notably the Koala, are able to digest eucalypt leaves also.

Research has shown that in the initial stages of stress, plants reallocate resources to parts of the plant important for core activities. Nutrients go into root and leaf development and not chemical defences, so that stressed plants have reduced chemical defences and are easier to eat or are more palatable. Plants change as they grow Plants have different stages of growth.

Toggle Caption Galls on eucalypt leaves, formed by insects. Toggle Caption Some sawfly Symphyta larvae can breakdown a plants chemical defence. References Anderson D. Below-ground herbivory in natural communities: A review emphasising fossorial animals. The Quarterly Review of Biology , 62 3 : Australian flora and vegetation statistics , Australian National Botanic Gardens. Bezemer T. Interactions between above- and below-ground insect herbivores as mediated by the plant defence system.

Oikos , 3 Bonkowski M and Scheu S Biotic interactions in the Rhizosphere: effects on plant growth and herbivore development. In Weisser W. Insects and ecosystem function. Ecological studies , Vol Chapman S. Insect herbivory increases litter quality and decomposition: an extension of the acceleration hypothesis. Ecology , 84 11 : Cooper P.