What do grizzly bears eat?
Grizzly bears (Ursus arctos horribilis) are opportunistic omnivores. Their annual diet is roughly 70 to 85 percent plant matter (roots, berries, bulbs, pine nuts, sedges) and 15 to 30 percent animal matter (salmon, ungulate calves, moths, carrion, rodents), although coastal populations flip this ratio during salmon runs and consume more than 40 kg of fish per day.
An Omnivore Built for Every Menu
A grizzly bear walks along a Yellowstone meadow in late May. The ground is still patched with snow. The bear stops every few meters, sniffs, and then plunges its forepaw into the turf to rip up the corm of a glacier lily. Forty kilometers away, a cow elk is dying of winterkill in a deadfall. Within three days, a different grizzly will find that carcass and eat 45 kg of putrefying flesh in a single sitting.
Six hundred kilometers west, on a gravel shoal of the Brooks River in Katmai National Park, another grizzly is standing belly-deep in moving water. A sockeye salmon, red-bodied and spawning, tries to push upstream past her. She drops her jaw in a single blur of motion and pins the fish, crushing its skull with a bite force near 1,250 PSI. She eats the skin, brain, and eggs first, leaves the rest for gulls, and wades back into position to catch the next one.
These three bears are the same species. They are all doing the same job, which is to convert whatever calorie source the landscape offers into fat that will carry them through a five to seven month winter fast. Understanding the grizzly bear as a North American predator starts with understanding that its menu is the most flexible of any large mammal on the continent.
"Grizzlies are the ultimate opportunists. Their diet shifts weekly with what is available. A bear on the Flathead River in June eats glacier lily corms; in August, the same bear is high on a talus slope turning over rocks for army cutworm moths; in October, it is killing elk calves in the aspen basins. No other large carnivore in North America moves between these food sources with such ease."
-- Chris Servheen, former Grizzly Bear Recovery Coordinator, U.S. Fish and Wildlife Service, in interview for High Country News (2016)
The Annual Diet by the Numbers
Across the grizzly's range, the mean composition of the diet varies more than in any other North American carnivore. The difference between a coastal Alaskan brown bear and an interior Yellowstone grizzly is the difference between an obligate fish specialist and a mostly vegetarian omnivore that occasionally kills. Both are Ursus arctos. Both are doing the same metabolic arithmetic. They just have different sources.
Mean annual diet composition (interior grizzly, Northern Rockies)
| Food category | Share of annual calories | Peak season |
|---|---|---|
| Roots, corms, bulbs (glacier lily, sweetvetch, biscuitroot) | 18 to 25% | April to June |
| Berries (buffaloberry, huckleberry, serviceberry, grouseberry) | 20 to 30% | July to September |
| Whitebark pine seeds (raided from red squirrel middens) | 10 to 30% (variable, mast cycle) | September to October |
| Army cutworm moths (Euxoa auxiliaris) | 5 to 15% (high elevation bears only) | July to August |
| Ungulate meat (elk calves, moose calves, adult carcasses, bison) | 10 to 25% | Year-round, peaking April to June |
| Salmon (coastal and interior salmon-bearing streams only) | 0 to 80% (population dependent) | July to October |
| Insects (ants, wasps, beetle larvae) | 2 to 5% | May to August |
| Rodents (voles, ground squirrels, marmots) | 2 to 5% | Year-round |
| Grasses, sedges, horsetails | 5 to 10% | May to July |
| Carrion (winter-killed ungulates, wolf kills, hunter gutpiles) | 5 to 15% | April to November |
| Human food and garbage (in conflict zones) | <5% (but causes most mortality) | Year-round |
Coastal populations (Katmai, Admiralty Island, Kodiak, Khutzeymateen, Kamchatka) replace the first three categories almost entirely with salmon during the run and with intertidal invertebrates, sedges, and berries during the rest of the year. Interior populations (Yellowstone, Northern Continental Divide, Selkirks, Cabinet-Yaak) have no meaningful fish component and rely on the plant, moth, and ungulate combination above.
Spring: Carcasses, Corms, and Calves
Grizzlies emerge from their dens between late March and early May depending on latitude, elevation, and sex. Males tend to emerge first and pregnant females last, because females with new cubs remain in the den to finish nursing. A bear leaves its den 15 to 30 percent lighter than when it entered, and the first priority on the outside is finding food that is already available before the plant growing season has begun.
Winter-killed ungulates
The single highest-calorie food of the spring is carrion. Elk, bison, moose, and deer that starved, fell through ice, or were swept away by avalanches over the winter emerge from snowmelt as semi-preserved 200 to 500 kg protein parcels. A grizzly that finds a fresh winter-kill can feed for three to five days, cache what it cannot eat under logs and dirt, and defend the cache from wolves, ravens, and other bears.
"Spring carrion is the single most important energy source for grizzlies coming out of hibernation in Yellowstone. A bear that locates two or three winter-killed bull elk in April is essentially guaranteed to make it to green-up in good condition. A bear that finds none has to work much harder to stay alive on roots and early grass."
-- Kerry Gunther and the Interagency Grizzly Bear Study Team, Yellowstone Science 22(1):19-29 (2014)
Ungulate calves
By late May the elk and moose calves begin to drop. For roughly six weeks, a grizzly can walk into a calving meadow and take newborn ungulates that are too weak to outrun it. Studies in the Greater Yellowstone Ecosystem show that grizzlies kill 20 to 50 elk calves per bear per spring, with the most efficient predators accounting for far more. Moose calves, particularly in the Gallatin and Madison ranges, are similarly vulnerable.
This spring meat pulse is the main reason adult grizzlies are considered effective ungulate predators rather than primary ones. They cannot catch healthy adult elk in a straight chase (elk run 70 km/h, grizzlies peak at 55 km/h for short bursts), but they do not need to. They only need to find the calves.
Roots and bulbs
Where meat is absent, grizzlies dig. Their 10 cm foreclaws, which evolved for exactly this purpose, turn over meadows in excavations that can be mistaken for tractor work. Key spring root foods include:
- Glacier lily corms (Erythronium grandiflorum): starchy, abundant on moist north-facing slopes, dug in enormous craters
- Sweetvetch roots (Hedysarum sulphurescens, H. alpinum): the "bear root" of Alaskan and Yukon grizzlies, a key pre-berry food
- Biscuitroot (Lomatium spp.): dry-slope corms, important in Idaho and Montana
- Spring beauty (Claytonia lanceolata) tubers: small but densely packed in subalpine meadows
- Cow parsnip (Heracleum maximum) shoots: eaten aboveground before the plant toughens
A single grizzly can dig dozens of square meters of meadow in a single afternoon.
Grasses and sedges
Before berries ripen and after roots become fibrous, grizzlies graze. A grizzly feeding on green grass looks like a shaggy brown cow. In late May and early June, grass and sedge can account for 50 percent of daily intake for brief periods. The calories are low per gram, but the vegetation is abundant and easy to digest, and it gets the bear through the weeks between winter-kill scavenging and the ripening of the first berries.
Summer: Moths, Berries, and the First Salmon
Army cutworm moths on talus slopes
One of the most striking grizzly feeding behaviors in North America happens between 3,000 and 3,700 m elevation in the Absaroka, Wind River, and Beartooth ranges of Wyoming and Montana. Between late July and early September, adult army cutworm moths (Euxoa auxiliaris) migrate upslope from lowland prairies and spend the warm months sheltering by day in the spaces between talus rocks. Grizzlies climb to the talus, roll rocks aside, and lick up the moths.
Each moth weighs about 0.4 g and contains roughly 0.2 kcal, most of which is fat laid down from nectar feeding on alpine wildflowers. A grizzly can eat 20,000 to 40,000 moths per day, yielding 4,000 to 8,000 kcal. In good moth years on good talus, a bear can build its fall reserves largely on insects.
"When we first documented bears eating moths on the Mirror Plateau, it was considered unusual. Now we understand it is a major energy source for a specific subset of high-country grizzlies. In certain years, cutworm moth sites may deliver up to 40 percent of a bear's late summer calories. These talus sites are essentially alpine grocery stores."
-- Tom Smith, Brigham Young University, Ursus 16(2):167-180 (2005)
Berries
No single food defines the summer grizzly better than berries. Starting with early buffaloberry (Shepherdia canadensis) and serviceberry (Amelanchier alnifolia) in July, progressing through huckleberries (Vaccinium membranaceum, V. globulare) in August, and finishing with grouseberry (V. scoparium) and low-bush cranberry in September, grizzlies gorge on fruit for weeks at a time.
A single grizzly may consume 200,000 berries in a single day during peak season. Buffaloberry alone can comprise 50 percent of late-July diet in the Yellowstone and Flathead ecosystems. The berries are low in fat but high in sugar, which the bear converts to fat through a hyperinsulinemic metabolism that would be diabetic in a human.
Ungulates in summer
Summer ungulate predation drops relative to spring, because calves can now run. Grizzlies continue to take elk, moose, and deer calves opportunistically, and in some regions they prey on weakened or injured adults. Yellowstone bears occasionally kill adult cow elk. Alaskan grizzlies take caribou calves and, rarely, adult caribou. This sits alongside the broader question of how grizzly bears compare to black bears, because black bears are far less effective ungulate predators than grizzlies at any season.
Fish
Interior grizzlies may eat cutthroat trout from small streams or spawning kokanee from alpine lakes, but the calories are marginal compared to salmon. Only coastal populations treat fish as a staple. For the full coastal feeding ecology see the section below on the salmon run.
Fall: Hyperphagia and the 20,000-Calorie Day
Between mid-August and mid-October, a grizzly's metabolic priority changes. The animal enters a physiological state called hyperphagia, from the Greek for "excessive eating." During hyperphagia, the bear spends 20 to 22 hours a day actively feeding and ingests up to 20,000 kcal. Body mass can increase by a kilogram per day. Fat deposition becomes the single organizing principle of the animal's behavior.
Why 20,000 calories matter
A hibernating grizzly loses 20 to 40 percent of its body mass over the winter. A 250 kg female enters her den in November and emerges in April weighing 150 to 200 kg. If she is pregnant, she births her cubs inside the den in January and nurses them on milk manufactured entirely from her own fat stores. By the time she leaves the den with newborn cubs, she may have burned 30 kg of her own body through lactation alone, in addition to the 40 to 60 kg burned through basal metabolism during the fast.
Every gram of fall fat is insurance against that winter loss. A bear that fails to reach target weight in fall will either not den successfully, will abort a pregnancy in utero, or will emerge too weak to hunt and feed herself. This is why grizzly bear hibernation works the way it does, and why fall food abundance is the single strongest predictor of population growth rate in any grizzly study ever conducted.
Key fall foods
| Food | Region | Kcal per 100 g | Notes |
|---|---|---|---|
| Whitebark pine seeds | Greater Yellowstone, Selkirks, Cabinets | 680 | Raided from red squirrel middens, high fat, rare in blister-rust-killed forests |
| Sockeye, coho, chum salmon | Coastal BC, Alaska | 200 | Whole fish with eggs; bears eat skin, brain, roe preferentially |
| Huckleberry | Northern Rockies, Cascades | 60 | Densely concentrated patches, 200,000 berries per day possible |
| Red huckleberry, kinnikinnick | Pacific Northwest | 55 | Bulk foods, low fat |
| Serviceberry | Interior West | 75 | August peak |
| Mountain ash berries | Cascades, Rockies | 65 | Late fall backup when preferred berries fail |
| Rosehips | Throughout range | 160 | High vitamin C, tough skins |
| Elk and deer carcasses (hunter gutpiles) | Multistate, Oct-Nov | 250 (mean) | Significant but also a major conflict and poaching risk |
| Chokecherry | Mountain West | 70 | Eaten whole, pits and all |
| Army cutworm moth (late aggregation) | High Rockies | 500 (dry) | Tapering from August peak |
Whitebark pine and the squirrel midden economy
In the Greater Yellowstone Ecosystem, whitebark pine seeds have historically been one of the three most important fall foods. Grizzlies do not harvest the cones directly. Red squirrels (Tamiasciurus hudsonicus) cut the cones from the trees in late summer and cache them in giant sub-shrub middens, sometimes containing 2,000 cones in a single heap. Grizzlies excavate these middens with their claws, crush the cones, and extract the seeds.
A single midden can provide a grizzly with 50,000 kcal in one sitting. In good mast years, whitebark pine seeds can make up 30 percent or more of fall calories. In poor mast years, they make up almost none, and bears compensate by eating more meat, more garbage, and more carrion, which drives them into conflict with humans. Mountain pine beetle outbreaks and white pine blister rust have killed enormous stands of whitebark pine since the 1990s, and the knock-on effects on grizzly fall diet are still being measured.
"In years when whitebark pine fails, Yellowstone grizzlies range farther, take more ungulates, and more frequently enter human-use areas. Food failure is not just an ecological statistic. It is a bear-human conflict statistic. Every poor pine year correlates with elevated bear mortality the following season."
-- Interagency Grizzly Bear Study Team, Monitoring Report 2019, p. 14
Coastal Grizzlies and the Salmon Run
Where salmon are abundant, everything changes. Coastal brown bears can grow twice as large as interior grizzlies not because they are a different species (they are not) but because they have access to a protein and fat source that interior bears simply do not. Understanding where grizzly bears live and the habitats available explains most of the size difference.
40 kg of salmon per day
In peak years on rivers like the Brooks, the Chilkoot, the Khutzeymateen, or the Karluk, an adult male brown bear can consume more than 40 kg of salmon in a 24-hour period. That is roughly 80,000 kcal, or enough to cover four days of hyperphagia demand in a single feeding bout. The bear catches a fish, eats the brain, skin, and eggs, drops the rest, and catches another.
This selective feeding is not wasteful. It is optimal. The brain and eggs carry the highest lipid concentration of any tissue in the salmon. When salmon are superabundant, eating only the most energy-dense portions maximizes caloric intake per hour of fishing. When the run tapers off, bears shift to eating the whole fish and eventually scavenge carcasses left by gulls, eagles, and other bears.
Salmon as an ecosystem engine
Coastal grizzlies move nitrogen from ocean to forest. A single large brown bear drags dozens of salmon per day from the stream into the adjacent forest to eat in cover. The carcasses and their nutrient content fertilize the soil. Isotope studies on western red cedars and Sitka spruce within 200 m of salmon streams show marine-derived nitrogen accounting for up to 40 percent of the trees' total nitrogen budget. The bears are, functionally, the ecosystem's circulatory system.
"Grizzlies on salmon rivers are not simply feeding. They are redistributing marine nutrients across kilometers of rainforest. Without the bears, the forests along these rivers would be measurably poorer. The trees themselves carry an isotopic signature that says: a bear ate a fish here, and the fish fed the forest."
-- Charlie Robbins, Washington State University, Canadian Journal of Zoology 81:1021-1030 (2003)
Comparison to interior populations
| Metric | Coastal brown bear (Katmai) | Interior grizzly (Yellowstone) |
|---|---|---|
| Adult male mass | 400 to 680 kg | 200 to 300 kg |
| Protein share of diet | 70 to 80% | 15 to 25% |
| Salmon share of annual calories | 50 to 80% | 0% |
| Berry share of annual calories | 10 to 20% | 25 to 40% |
| Whitebark pine contribution | 0% | 0 to 30% |
| Ungulate calf predation | Low to moderate | Moderate to high |
| Population density | Up to 500 per 1,000 km² | 10 to 30 per 1,000 km² |
Both of these are Ursus arctos. The larger form is called the brown bear in most of the scientific and conservation literature, although the subspecific naming (Kodiak, peninsular, coastal brown, grizzly) is a matter of geography more than biology. The overall species hub for the grizzly bear as a North American predator covers the taxonomy in detail.
Small Prey and the Invertebrate Menu
Alongside the headline foods, grizzlies eat a great deal of what most people would not recognize as bear food.
Rodents and small mammals:
- Ground squirrels (Urocitellus columbianus, U. parryii): dug from burrows, especially in Yukon and Alaskan alpine
- Marmots (Marmota caligata, M. flaviventris): targeted in late summer when fat
- Voles and mice (Microtus, Myodes): dug from meadow runways
- Pikas (Ochotona princeps): occasional, in talus
Insects:
- Ants (Formica and Camponotus spp.): colonies torn open from rotten logs, a staple summer protein source
- Wasps and hornets: nests excavated, bears eat adults, larvae, and honey
- Beetle grubs: inside rotting wood, extracted with teeth and claws
- Army cutworm moth adults: on talus slopes, as described above
A 200 kg grizzly that tears apart an ant log eats 20,000 to 40,000 ants in a sitting, which is thousands of kilocalories of pure protein. Anting behavior can account for 5 percent of a summer bear's annual calories.
Carrion, Ungulate Predation, and the Meat Question
"Do grizzlies eat meat?" is one of the most common reader queries, and the answer is yes, substantially, but less than many people assume.
How much meat?
In most interior populations, animal matter totals 15 to 30 percent of annual calories. In coastal populations with salmon, animal matter is 70 to 85 percent. In Yellowstone specifically, the Interagency Grizzly Bear Study Team's long-term monitoring puts ungulate meat at roughly 15 to 25 percent of adult male calories and 10 to 20 percent of adult female calories.
How grizzlies take adult ungulates
Grizzlies rarely run down healthy adult elk or moose. When they do take adults, it usually happens through one of the following:
- Ambush in deep snow, when the ungulate cannot outrun the bear
- Pursuit of wounded animals injured by other predators, hunters, or vehicle collision
- Kleptoparasitism from wolf kills, where the grizzly arrives after the wolves have already downed the animal
- Opportunistic predation on old, sick, or birthing females too compromised to escape
- Defense-turned-predation during unexpected close-range encounters in dense cover
Wolves and grizzlies have a complicated relationship on landscapes where both occur. Wolves do the killing, grizzlies arrive, and the wolves typically yield the carcass to the larger bear. Studies in Yellowstone found that grizzlies displaced wolves from their kills about 80 percent of the time when both species were present at the carcass.
Carrion
Beyond fresh kills, grizzlies are opportunistic scavengers. They will eat carcasses ranging from weeks-old roadkill to beached marine mammals. Their digestive tract tolerates bacterial loads that would sicken a human many times over. During hunting season, gutpiles left by elk and deer hunters in the fall mountains represent a significant (and dangerous to bears) food source.
Human Food, Garbage, and Bear Mortality
The darkest chapter of the grizzly diet story is what happens when bears discover human food. Garbage, unsecured food at campsites, livestock grain, beehives, and fruit trees in rural yards all provide calorie-dense, effort-free nutrition. A bear that learns to associate humans with food rarely stops.
The Yellowstone garbage dumps
Through the 1950s and 1960s, the National Park Service operated open garbage dumps at Yellowstone hotels. Grizzlies fed at these dumps nightly. When the dumps were closed in 1968 to 1971 to reduce habituation, dozens of displaced bears moved into campgrounds and developed areas searching for replacement calories, and many were killed as a result. The closure itself was ecologically correct, but it caused a spike in bear mortality that echoed through the population for a decade.
"The Yellowstone dump closures taught us that bears with a learned association to human food cannot be 'un-taught' in the wild. The only long-term answer is to prevent the association from forming in the first place. Every unsecured food storage box, every open dumpster, every left-out dog bowl is a future dead bear."
-- Yellowstone Interagency Grizzly Bear Study Team, cited in Craighead et al., The Grizzly Bears of Yellowstone (1995)
The lesson transfers to every modern bear country. Bear-resistant food storage containers, electric fencing around orchards and beehives, and community cleanup of attractants are now the standard toolkit for reducing conflict-related bear mortality. For the full picture of human-bear interaction and risk management, see are grizzly bears dangerous to humans.
Seasonal Diet at a Glance
The grizzly's year breaks into four functional phases, each with its own dominant food class.
Spring (late March to early June): Emerging from den at 70 to 85 percent of pre-denning mass. Targets winter-killed ungulates, newborn elk and moose calves, early corms (glacier lily, sweetvetch), grass, and sedge. Meat share is high relative to annual average.
Early summer (June to mid-July): Meat pulse tapers as calves mature. Bears shift to grasses, horsetails, cow parsnip, insect colonies, and rodents. Berries begin to ripen at lower elevations.
Late summer (mid-July to late August): Peak berry feeding. Buffaloberry and huckleberry dominate. Army cutworm moths active on high talus. Salmon begin running in coastal systems.
Fall hyperphagia (late August to October): The caloric sprint. Whitebark pine mast (in good years), continued berry feeding, peak salmon run in coastal populations, hunter gutpiles in late October. Bears can eat 20,000 kcal per day and gain 1 kg of mass daily.
Winter (November to March): Hibernation. Food intake effectively zero. Bears survive on stored fat and produce cubs during the fast. See grizzly bear cubs and family life for the denning biology of mothers and cubs.
Diet Differences by Ecosystem
Not all grizzlies eat the same things, because not all habitats offer the same foods. Here is how the menu differs across the main populations.
Katmai and the Alaska Peninsula
Dominated by salmon from June through October. Sedges and intertidal clams in spring. Berries in late summer. Moose and caribou calves taken seasonally. Adult males are the heaviest grizzlies in the world, routinely exceeding 500 kg.
Kodiak Island
A subspecies (U. a. middendorffi) isolated on salmon-rich islands. Diet is roughly half salmon and half plant and berry material. Extremely high bear densities.
Coastal British Columbia (Khutzeymateen, Great Bear Rainforest)
Salmon in fall, crabs and mussels on intertidal flats, sedges in spring meadows. Spirit bears (white-phase black bears) share the ecosystem but not the diet profile.
Northern Continental Divide Ecosystem (Montana)
No salmon. Berries, whitebark pine seeds (declining due to blister rust), glacier lily, cutworm moths, ungulate calves, carrion. Largest contiguous US population south of Canada.
Greater Yellowstone Ecosystem
No salmon. Heavily reliant on whitebark pine in good mast years, cutworm moths in summer, bison and elk meat year-round, berries in limited supply compared to more northerly ranges. Genetically isolated from other populations.
Selkirk, Cabinet-Yaak, North Cascades
Small, fragmented populations. Berries, roots, carrion, limited ungulate predation. Recovery efforts ongoing.
Barren-Ground grizzlies (Yukon, NWT, Nunavut)
Tundra-adapted. Ground squirrels and caribou calves become disproportionately important. Berries in late summer. No salmon in most areas. Smaller average body size.
For an overview of population distribution across these ecosystems, see where do grizzly bears live.
Comparison with Other Bears
Grizzlies are the most dietarily flexible bear species on Earth. A quick look at the other seven bears puts the grizzly's menu in context:
- Polar bears are near-obligate seal predators, 90+ percent carnivorous. See what polar bears eat for the full breakdown.
- Black bears are 75 to 85 percent plant-based, with some carrion and small mammals. Smaller ungulate predation than grizzlies.
- Giant pandas are 99 percent bamboo specialists.
- Sun bears, spectacled bears, sloth bears focus on fruit, insects, and tree nectar.
- Asiatic black bears are omnivores similar to American black bears.
No other bear species consistently moves between 80 percent plant and 80 percent meat within a single twelve-month cycle. That capacity for trophic flexibility is why grizzlies historically occupied every biome from Mexican deserts to the Arctic tundra.
Feeding Anatomy: The Dentition of an Omnivore
A grizzly's skull is the skull of an animal that has made no evolutionary commitment to one food type. Both carnivore and herbivore features are present.
Canines: Large, conical, 5 to 8 cm exposed length. Built for piercing hide and flesh. Comparable to a lion's canines in size and function.
Molars: Broad, flat, with heavy enamel. Built for crushing and grinding. Similar in structure to the molars of a pig or a human, not those of a true carnivore. The carnassial shear characteristic of cats and canids has been largely lost.
Jaw musculature: Massive temporalis and masseter muscles anchored to a prominent sagittal crest. Bite force near 1,250 PSI. Capable of crushing elk femurs to reach the marrow.
Claws: 8 to 10 cm, non-retractable, slightly curved. Used as digging tools as much as weapons. Separates grizzlies from the straight-clawed, smaller-clawed black bear instantly in track identification.
This skeletal layout means a grizzly can switch in seconds from peeling bark for ants to crushing a salmon skull to excavating a whitebark pine midden to grinding down a kilo of serviceberry. The dentition is a metabolic passport.
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References
- Hilderbrand, G. V., Schwartz, C. C., Robbins, C. T., Jacoby, M. E., Hanley, T. A., Arthur, S. M., & Servheen, C. (1999). The importance of meat, particularly salmon, to body size, population productivity, and conservation of North American brown bears. Canadian Journal of Zoology, 77(1), 132-138. https://doi.org/10.1139/z98-195
- Mattson, D. J., Blanchard, B. M., & Knight, R. R. (1991). Food habits of Yellowstone grizzly bears, 1977-1987. Canadian Journal of Zoology, 69(6), 1619-1629. https://doi.org/10.1139/z91-226
- Robbins, C. T., Schwartz, C. C., & Felicetti, L. A. (2004). Nutritional ecology of ursids: A review of newer methods and management implications. Ursus, 15(2), 161-171. https://doi.org/10.2192/1537-6176(2004)015<0161:NEOUAR>2.0.CO;2
- French, S. P., French, M. G., & Knight, R. R. (1994). Grizzly bear use of army cutworm moths in the Yellowstone ecosystem. Bears: Their Biology and Management, 9(1), 389-399. https://doi.org/10.2307/3872728
- Gunther, K. A., Shoemaker, R. R., Frey, K. L., Haroldson, M. A., Cain, S. L., van Manen, F. T., & Fortin, J. K. (2014). Dietary breadth of grizzly bears in the Greater Yellowstone Ecosystem. Ursus, 25(1), 60-72. https://doi.org/10.2192/URSUS-D-13-00008.1
- Schwartz, C. C., Fortin, J. K., Teisberg, J. E., Haroldson, M. A., Servheen, C., Robbins, C. T., & van Manen, F. T. (2014). Body and diet composition of sympatric black and grizzly bears in the Greater Yellowstone Ecosystem. Journal of Wildlife Management, 78(1), 68-78. https://doi.org/10.1002/jwmg.633
- Nelson, R. A., Folk, G. E., Pfeiffer, E. W., Craighead, J. J., Jonkel, C. J., & Steiger, D. L. (1983). Behavior, biochemistry, and hibernation in black, grizzly, and polar bears. Bears: Their Biology and Management, 5, 284-290. https://doi.org/10.2307/3872551
- Fortin, J. K., Schwartz, C. C., Gunther, K. A., Teisberg, J. E., Haroldson, M. A., Evans, M. A., & Robbins, C. T. (2013). Dietary opportunism of grizzly bears in the Greater Yellowstone Ecosystem. Journal of Wildlife Management, 77(2), 270-281. https://doi.org/10.1002/jwmg.483