Omnivores in Yellowstone National Park include animals that eat both plant and animal matter. Their diets vary by species and may include grasses, roots, berries, seeds, insects, fish, eggs, small mammals, and carrion. This dietary flexibility allows them to use a variety of food sources across the park’s forests, grasslands, wetlands, and other habitats.
These animals obtain food in different ways, from foraging for fruits and seeds to hunting small prey and scavenging carcasses. Their diets also change with the seasons as food availability shifts throughout the year. By consuming different types of food, omnivores form important connections within Yellowstone’s food web.
Table of Contents
Quick Reference: Omnivores in Yellowstone National Park
| Omnivore | Plant Foods | Animal Foods |
|---|---|---|
| Grizzly Bear | Grasses, roots, berries, whitebark pine seeds | Insects, fish, small mammals, carrion |
| American Black Bear | Grasses, berries, roots, fruits, nuts | Insects, fish, small mammals, eggs, carrion |
| Coyote | Berries, fruits | Rodents, rabbits, insects, carrion |
| Common Raven | Berries, fruits, seeds | Carrion, insects, eggs, small animals |
| Red Fox | Berries, fruits | Mice, voles, rabbits, birds, insects, carrion |
| Striped Skunk | Fruits, berries | Insects, grubs, small rodents, eggs, frogs, carrion |
| Raccoon | Fruits, berries, nuts | Insects, crayfish, fish, eggs, frogs, carrion, small animals |
| American Marten | Berries, fruits | Small mammals, birds, insects, amphibians, reptiles, carrion |
| Trumpeter Swan | Aquatic plants, grasses | Aquatic invertebrates |
| Clark’s Nutcracker | Pine seeds, berries | Insects and other small invertebrates |
| American Robin | Berries, fruits | Earthworms, insects, other invertebrates |
| Black-Billed Magpie | Seeds, berries, fruits | Insects, eggs, small animals, carrion |
Grizzly Bear (Ursus arctos horribilis)
Grizzly bears are among the most versatile omnivores in Yellowstone National Park. Their diet includes grasses, roots, berries, pine nuts, insects, fish, and animal matter. They also consume carrion and may prey on elk calves and other vulnerable animals when opportunities arise. The proportions of these foods vary with the season, habitat, and availability of resources.
During spring, grizzly bears may feed on winter-killed animals, roots, and emerging vegetation. In summer and fall, they consume berries, grasses, army cutworm moths in high-elevation areas, and other calorie-rich foods that help them build fat reserves before winter. By feeding on both plants and animals, grizzly bears influence food webs and contribute to nutrient movement throughout Yellowstone’s ecosystems.
American Black Bear (Ursus americanus)
American black bears are omnivores found in Yellowstone National Park, where they forage across forests, meadows, and other habitats. Plant foods make up a substantial part of their diet, including grasses, roots, berries, nuts, and other seasonal vegetation. They also eat insects, fish when available, small mammals, and carrion.
Their feeding habits change throughout the year as different foods become available. In spring, black bears may feed on newly emerging plants and animal carcasses. During summer and fall, berries, nuts, and other energy-rich foods become important as bears build fat reserves before winter. Although their diet overlaps with that of grizzly bears, differences in habitat use and feeding behavior can help the two species make use of different food resources.
Coyote (Canis latrans)
Coyotes are adaptable omnivores in Yellowstone National Park, feeding on a combination of animal prey and plant material. Their diet consists mainly of voles, mice, rabbits, other small animals, and carrion. They may also consume berries and other plant material when available, making them opportunistic omnivores.
Their feeding habits shift with changes in prey abundance, weather, and seasonal food availability. During warmer months, coyotes may consume fruits and insects alongside small mammals. In winter, they rely more heavily on available animal food, including rodents and carrion. By consuming small mammals and scavenging carcasses, coyotes contribute to Yellowstone’s food web and help transfer energy between different parts of the ecosystem.
Common Raven (Corvus corax)
Common ravens are highly adaptable omnivorous birds found throughout Yellowstone National Park. Their diet includes insects, berries, seeds, eggs, small animals, and carrion. They frequently feed on the remains of animals killed by wolves and other predators, making them important scavengers in Yellowstone’s ecosystem.
Ravens take advantage of different food sources throughout the year. During winter, carcasses can provide an important source of food when other resources are limited. In warmer months, insects, eggs, and fruits add variety to their diet. Their ability to locate food and exploit feeding opportunities allows them to survive in diverse habitats, from open grasslands to forest edges and rugged mountain terrain.
Red Fox (Vulpes vulpes)
Red foxes are opportunistic omnivores that feed on a mixture of animal prey and plant foods in Yellowstone National Park. Their diet consists mainly of small mammals such as mice and voles, rabbits, birds, and insects. They also eat carrion, particularly in winter, along with berries and other plant material when available.
During warmer months, red foxes may eat insects and berries alongside small mammals. In winter, they depend more heavily on available prey, including rodents beneath the snow, as well as carrion when they encounter it. This flexible diet helps red foxes use Yellowstone’s varied habitats, including meadows, shrublands, and forest edges. By consuming small animals and seasonal plant foods, they participate in several interconnected parts of the park’s food web.
Striped Skunk (Mephitis mephitis)
Striped skunks (Mephitis mephitis) are nocturnal omnivores found in the Greater Yellowstone Ecosystem. They feed on a varied diet that includes insects, grubs, beetles, small rodents, eggs, and other small animals, as well as berries, fruits, and other plant material. Insects and other invertebrates can make up a substantial part of their diet, particularly during warmer months.
Their feeding habits change with the seasons and the availability of food. During spring and summer, striped skunks forage for insects and other invertebrates, while fruits and berries provide additional food when available. They may also consume small vertebrates and scavenge animal remains. By feeding on both plant and animal matter, striped skunks make use of a variety of food resources across the habitats they occupy.
Raccoon (Procyon lotor)
Raccoons (Procyon lotor) are adaptable omnivorous mammals found in the Greater Yellowstone Ecosystem. They feed on a wide variety of foods, including berries, fruits, nuts, insects, crayfish, fish, frogs, eggs, small mammals, and carrion. Their flexible diet allows them to take advantage of different food sources in wooded areas, wetlands, and habitats near streams and ponds.
Raccoons adjust their feeding habits according to seasonal food availability. In spring, they consume insects, crayfish, and other small animals, while fruits and berries become important during summer. In fall, nuts and seeds provide additional energy. This varied diet helps raccoons survive changing environmental conditions and makes them versatile foragers within the ecosystems they inhabit.
Marten (Martes americana)
Martens (Martes americana), also known as American martens, are small, forest-dwelling mammals in the weasel family found in Yellowstone National Park. They inhabit coniferous forests with fallen logs, tree stumps, and dense understory vegetation that provide shelter and foraging opportunities. Although they primarily eat small mammals, martens are omnivores because their diet also includes insects, berries, fruit, and other plant material.
Small mammals such as voles, mice, red squirrels, chipmunks, and shrews make up much of their diet. Martens also eat birds, eggs, amphibians, reptiles, and carrion when available. During summer, their diet may become more varied as insects, fruits, and berries become accessible. This ability to use both animal and plant food sources helps martens survive in Yellowstone’s forest ecosystems throughout the year.
Trumpeter Swan (Cygnus buccinator)
Trumpeter swans feed primarily on aquatic vegetation, including pondweeds, sedges, and other submerged or emergent plants. They may also consume small aquatic invertebrates, such as insects and their larvae, particularly while feeding in shallow water. This combination of plant material and animal foods can give them an omnivorous diet, although vegetation makes up the main part of their food intake.
Their feeding habits vary with habitat and food availability. Swans reach underwater plants by dipping their long necks beneath the surface in shallow wetlands, ponds, and lakes. Animal matter provides a supplementary food source rather than the main component of their diet.
Clark’s Nutcrackers (Nucifraga columbiana)
Clark’s nutcrackers are omnivorous birds found in Yellowstone National Park, particularly in coniferous forests and mountainous habitats. Their diet includes pine seeds, insects, berries, and other small food items. Seeds from whitebark pine are especially important when available, providing an energy-rich food source.
These birds also collect and cache seeds in the ground for later consumption. Seeds that remain uneaten may germinate, helping whitebark pines regenerate and spread. During the breeding season, Clark’s nutcrackers also feed insects and other animal matter to their young. Their combination of seed eating and insect consumption makes them an important link between Yellowstone’s plant communities and animal food webs.
American Robins (Turdus migratorius)
American robins are omnivorous birds found in Yellowstone National Park’s forests, meadows, and open areas. Their diet includes earthworms, insects, and other small invertebrates, along with berries and other fruits. The balance between animal and plant foods changes with the season and the availability of different resources.
During spring and summer, robins forage on earthworms and insects, which provide protein for adults and growing chicks. As summer progresses and into fall, berries and other fruits become increasingly important. This varied diet allows American robins to use different habitats and food sources throughout the year. By consuming fruits, they can also disperse seeds, while their feeding on invertebrates connects them to other levels of Yellowstone’s food web.
Black-Billed Magpies (Pica hudsonia)
Black-billed magpies are opportunistic omnivorous birds found in Yellowstone National Park and the surrounding Greater Yellowstone Ecosystem. Their diet includes insects, seeds, berries, eggs, small animals, and carrion. This varied diet allows them to take advantage of different food sources across open habitats, shrublands, and forest edges.
During warmer months, magpies feed on insects and other invertebrates, along with fruits and seeds when available. They also scavenge animal remains and may eat eggs or small vertebrates. In winter, carrion and other accessible food sources become particularly useful. By consuming both plant and animal matter, black-billed magpies contribute to Yellowstone’s food web as both foragers and scavengers.