Herbivores, Carnivores and Omnivores: Examples of Each

Herbivores, carnivores and omnivores at a glance

Most animals do not fit perfectly into one box. Many herbivores swallow insects with their leaves, and many carnivores eat a little fruit. Scientists usually classify an animal by what makes up most of its diet.

What is a herbivore?

A herbivore is an animal that feeds mainly on plants or algae. Grazers such as zebras and bison eat grass, browsers such as giraffes and moose eat leaves and twigs from trees and shrubs, frugivores specialize in fruit, and nectar feeders drink the sugary liquid in flowers.

Plants are easy to catch but hard to digest, because their cell walls are made of tough cellulose. Herbivores have broad, flat teeth for grinding and long digestive systems packed with bacteria and other microbes that break cellulose down. Cows, deer and giraffes are ruminants: they have a four-chambered stomach and chew their food twice, bringing it back up as cud.

12 examples of herbivores

• African bush elephant: the largest land animal eats about 150 kg (330 lb) of grass, leaves, bark and fruit a day.
• Giraffe: uses its long, dark tongue to strip leaves from thorny acacia trees.
• Koala: the koala eats almost nothing but eucalyptus leaves, which are toxic to most other mammals.
• Hippopotamus: leaves the water at night to graze on short grass.
• American bison: a grazer that once roamed North America’s prairies in millions.
• European rabbit: eats grass and herbs and swallows some of its own soft droppings to digest its food a second time.
• Beaver: eats bark, twigs and water plants, and stores branches underwater for winter.
• Green iguana: one of the few lizards that eats mostly leaves, flowers and fruit.
• West Indian manatee: a slow “sea cow” that grazes on seagrass and other water plants.
• Green sea turtle: adults feed mainly on seagrass and algae.
• Grasshoppers and caterpillars: some of the most numerous plant-eaters on Earth.
• Parrotfish: scrape algae from coral with beak-like teeth, grinding up rock that later becomes white sand.

What is a carnivore?

A carnivore is an animal whose diet is made up mostly of other animals. Hypercarnivores get more than 70% of their food from meat, and obligate carnivores, such as all members of the cat family, must eat meat to survive because they cannot make certain nutrients from plant food. Meat is rich in energy and easy to digest, so carnivores usually have short guts, sharp teeth or beaks, and keen senses for finding prey.

Carnivores can hunt, scavenge, or both. Insectivores (insect-eaters) and piscivores (fish-eaters) are specialized kinds of carnivores.

12 examples of carnivores

• Lion: the lion hunts mainly large hoofed mammals such as wildebeest, zebras and buffalo.
• Tiger: the largest cat ambushes deer and wild pigs in forests and grasslands of Asia.
• Polar bear: the most meat-dependent bear, hunting seals from the sea ice.
• Gray wolf: packs chase deer, elk and moose.
• Orca: different populations specialize in fish, seals or even other whales.
• Great white shark: eats fish, rays, seals and the carcasses of whales.
• Peregrine falcon: catches other birds in midair after a high-speed dive.
• Saltwater crocodile: the largest living reptile ambushes fish, birds and mammals at the water’s edge.
• Snakes: every snake species is a carnivore, from egg-eating snakes to giant pythons.
• Spiders: nearly all spiders are predators of insects and other small animals; see What do spiders eat?
• Dragonflies: catch flying insects in midair, while their young hunt tadpoles and small fish underwater.
• Octopus: pounces on crabs and clams and can drill through shells.

What is an omnivore?

An omnivore regularly eats both plant and animal foods. Being flexible helps omnivores survive when one kind of food runs short, which is why many of them, such as raccoons, foxes and crows, live comfortably near people. Their teeth are usually a mix of sharp front teeth and flatter back teeth for chewing.

12 examples of omnivores

• Brown bear: a brown bear eats mostly grasses, roots, berries and nuts, plus insects, salmon, rodents and carrion.
• American black bear: eats mostly grasses, berries, nuts and acorns, plus insects, fish and carrion.
• Red fox: eats voles, mice and rabbits, plus beetles, earthworms, berries and fruit.
• Raccoon: eats crayfish, frogs, eggs, fruit, nuts and food waste.
• Wild boar: roots up bulbs, acorns and worms, and eats eggs and small animals.
• Chimpanzee: eats mostly fruit and leaves, but groups also hunt monkeys.
• Humans: eat a wide range of plant and animal foods.
• Common raven and crows: eat carrion, insects, seeds, grain and fruit.
• European badger: earthworms are its main food, along with insects, fruit and bulbs.
• Virginia opossum: eats insects, carrion, fruit, eggs and small animals.
• Red junglefowl: the wild ancestor of the chicken scratches the ground for seeds and insects.
• Eastern box turtle: eats worms, slugs, insects, berries and mushrooms.

Insectivores, scavengers and filter feeders

Insectivores eat mainly insects and other small invertebrates. The aardvark, giant anteater and pangolins lap up ants and termites with long, sticky tongues, while most bats in Europe and North America catch moths and other insects in flight. Hedgehogs, swallows, swifts, chameleons and most adult frogs are insectivores too.

Scavengers eat animals that are already dead. Vultures are the only vertebrates that rely almost entirely on carrion, soaring for hours to find it. Tasmanian devils both hunt and scavenge, and burying beetles bury small dead animals to feed their larvae. Spotted hyenas have a reputation as scavengers, but they actually kill most of their own food.

Filter feeders strain small food from water. The blue whale gulps huge mouthfuls of seawater and pushes it out through its baleen plates, trapping tiny shrimp-like krill. Whale sharks, basking sharks, manta rays, flamingos, mussels, oysters and sponges all filter feed in their own way.

Surprising diets that break the rules

• Giant panda: a member of the order Carnivora that has become a herbivore. Bamboo makes up about 99% of its diet, but the giant panda still has a meat-eater’s short gut, so it must eat for 10–16 hours a day. Read more in What do pandas eat?
• A vegetarian spider: Bagheera kiplingi, a jumping spider from Mexico and Central America, eats mostly protein-rich tips of acacia leaves that the trees produce for ants, according to a 2009 study.
• Hippos and deer: these herbivores have occasionally been seen eating meat. Hippos sometimes scavenge carcasses, and deer have been recorded eating bird eggs and nestlings, possibly for extra minerals.
• Sea turtles and frogs: young green sea turtles eat jellyfish and other small animals before switching to plants, while frogs do the opposite: many tadpoles graze on algae, but adult frogs are carnivores.

Where herbivores, carnivores and omnivores fit in a food chain

A food chain shows who eats whom. It starts with producers, such as plants and algae, which make their own food from sunlight. Herbivores are primary consumers because they eat the producers. Carnivores and omnivores that eat herbivores are secondary consumers, and predators that eat other predators are tertiary consumers. Apex predators, such as orcas and lions, sit at the top with no natural enemies as adults.

Two simple examples are grass, zebra and lion on the African savanna, and microscopic algae, krill, Adélie penguin and leopard seal in the Southern Ocean. Decomposers such as fungi, bacteria and earthworms break down dead plants and animals at every level and return nutrients to the soil.

Only about 10% of the energy at one level is passed on to the next; the rest is used for living or lost as heat. That is why there are always far more plants than herbivores and far more herbivores than predators. Because omnivores feed at several levels at once, real ecosystems are tangled food webs rather than neat chains.