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Brown Bear

Ursus arctos

Mammal · family Ursidae · order Carnivora

  1. G1
    Critically imperiled
  2. G2
    Imperiled
  3. G3
    Vulnerable
  4. G4
    Apparently secure
  5. G5
    Secure

NatureServe global rank G4: apparently secure[2].

Updated October 30, 2026. Published by Humblebee.

Brown Bear
Photo: Robert F. Tobler, CC BY-SA 4.0, via Wikimedia Commons.
Endangered Species Act
Not listed[1]
NatureServe global rank
G4 Apparently Secure[2]
Native in
5 states[3]
Longest recorded life
40 years[4]

The Brown Bear (Ursus arctos) is a large mammal in the bear family, also called the Grizzly Bear[5][6]. In the United States, NatureServe lists it as native in Alaska, Idaho, Montana, Washington and Wyoming[3].

Conservation status

The Brown Bear is not listed as endangered or threatened under the US Endangered Species Act in USFWS data[1]. NatureServe ranks it G4 (Apparently Secure) worldwide and N3 (Vulnerable) in the United States[2][7]. The IUCN Red List category recorded by NatureServe is Least concern[8]. International trade is controlled under CITES Appendix II[9].

Status Value
Endangered Species Act[1] Not listed
NatureServe global rank[2] G4 (Apparently Secure)
NatureServe US rank[7] N3 (Vulnerable)
IUCN Red List (via NatureServe)[8] Least concern
CITES (international trade)[9] Appendix II
Total population (NatureServe estimate)[10] 100,000 to 1,000,000 individuals

Where Brown Bear lives

NatureServe lists the Brown Bear as native in Alaska, Idaho, Montana, Washington and Wyoming[3]. It ranks the bear as extirpated or possibly extirpated, meaning gone or possibly gone, in Arizona, California, Colorado, Kansas, Minnesota, North Dakota, Nebraska, New Mexico, Nevada, Oklahoma, Oregon, South Dakota, Texas and Utah[11].

Alaska: native, state rank S4AKMaine: not recordedMEWisconsin: not recordedWIVermont: not recordedVTNew Hampshire: not recordedNHWashington: native, state rank S1WAIdaho: native, state rank SNRIDMontana: native, state rank S3MTNorth Dakota: extirpated or possibly extirpated, state rank SXNDMinnesota: extirpated or possibly extirpated, state rank SXMNIllinois: not recordedILMichigan: not recordedMINew York: not recordedNYMassachusetts: not recordedMAOregon: extirpated or possibly extirpated, state rank SXORNevada: extirpated or possibly extirpated, state rank SXNVWyoming: native, state rank S1WYSouth Dakota: extirpated or possibly extirpated, state rank SXSDIowa: not recordedIAIndiana: not recordedINOhio: not recordedOHPennsylvania: not recordedPANew Jersey: not recordedNJConnecticut: not recordedCTRhode Island: not recordedRICalifornia: extirpated or possibly extirpated, state rank SXCAUtah: extirpated or possibly extirpated, state rank SXUTColorado: extirpated or possibly extirpated, state rank SXCONebraska: extirpated or possibly extirpated, state rank SXNEMissouri: not recordedMOKentucky: not recordedKYWest Virginia: not recordedWVVirginia: not recordedVAMaryland: not recordedMDDelaware: not recordedDEArizona: extirpated or possibly extirpated, state rank SXAZNew Mexico: extirpated or possibly extirpated, state rank SXNMKansas: extirpated or possibly extirpated, state rank SXKSArkansas: not recordedARTennessee: not recordedTNNorth Carolina: not recordedNCSouth Carolina: not recordedSCDistrict of Columbia: not recordedDCOklahoma: extirpated or possibly extirpated, state rank SXOKLouisiana: not recordedLAMississippi: not recordedMSAlabama: not recordedALGeorgia: not recordedGAHawaii: not recordedHITexas: extirpated or possibly extirpated, state rank SXTXFlorida: not recordedFLPuerto Rico: not recordedPR
State presence as recorded by NatureServe[12].
Show state ranks (19 states)
StateRankMeaning
AlaskaS4Apparently Secure
ArizonaSXPresumed Extirpated
CaliforniaSXPresumed Extirpated
ColoradoSXPresumed Extirpated
IdahoSNRNot Ranked
KansasSXPresumed Extirpated
MinnesotaSXPresumed Extirpated
MontanaS3Vulnerable
NebraskaSXPresumed Extirpated
NevadaSXPresumed Extirpated
New MexicoSXPresumed Extirpated
North DakotaSXPresumed Extirpated
OklahomaSXPresumed Extirpated
OregonSXPresumed Extirpated
South DakotaSXPresumed Extirpated
TexasSXPresumed Extirpated
UtahSXPresumed Extirpated
WashingtonS1Critically Imperiled
WyomingS1Critically Imperiled

Habitat

Today the Brown Bear lives mainly on arctic and alpine tundra and in mountain forests[13]. In the past it also lived in open prairie, brushland and semidesert scrub[13]. NatureServe records forest, woodland, shrubland, grassland, alpine, tundra and riparian (streamside) habitat for it[14]. Most populations need very large areas[13].

Habitat types recorded by NatureServe[14]

Size, diet and lifespan

NatureServe records a typical length of 213 cm (84 in) and a typical adult weight of 680 kg (1499 lb)[15][16]. The bear eats both plants and animals. One estimate puts its diet at 60% plant material other than fruit, 20% fruit, 10% warm-blooded animals and 10% invertebrates[17]. Litters hold 1 to 4 young, with an average of 2[18]. The longest recorded lifespan is 40 years, in captivity[4].

Trait Value
Typical length[15] 213 cm (84 in)
Typical adult weight[16] 680 kg (1499 lb)
Longest recorded lifespan (AnAge)[4] 40 years (captivity)
Litter or clutch size[19] 2
Gestation or incubation[20] 103 days
Female maturity[21] 1,313 days (about 3.6 years)
Food habits[22] Carnivore, Piscivore, Invertivore, Herbivore, Granivore, Frugivore
Active[23] crepuscular, diurnal
Migration[24] non-migrant, local migrant

Estimated diet composition (EltonTraits 1.0)[17]

  • 60% other plant material
  • 20% fruit
  • 10% warm-blooded vertebrates
  • 10% invertebrates

When to look for it

The Brown Bear is often crepuscular, which means most active around dawn and dusk[25]. In winter it is dormant in a den[25]. In North America it usually enters the den in October or November and comes out in April or May[25]. Observation records on GBIF in the United States are highest in May, June and August, which shows when people report bears, not how many there are[26].

January: 33 recordsJanFebruary: 16 recordsFebMarch: 52 recordsMarApril: 217 recordsAprMay: 1,599 recordsMayJune: 1,655 recordsJunJuly: 1,557 recordsJulAugust: 1,625 recordsAugSeptember: 1,429 recordsSepOctober: 592 recordsOctNovember: 168 recordsNovDecember: 68 recordsDec
US observation records on GBIF by month, all years. The three months with the most records are highlighted. Records show when people look and report, not how many animals there are[26].
Show records by month
MonthRecords
January33
February16
March52
April217
May1,599
June1,655
July1,557
August1,625
September1,429
October592
November168
December68

Where to see it

National Park Service species lists record Brown Bear as present in 17 park units[27]. Present means the park has a confirmed record, not that sightings are common.

States with the most GBIF observation records: Alaska, Wyoming, Montana, California, Colorado[28]. These counts follow where people look and report, not population size.

Safety around this animal

These tips are quoted in summary from official agencies. We add no advice of our own. Follow local rules and the agency pages linked below.

From National Park Service

  • Stay calm and talk to the bear in a calm voice. Stand still and slowly wave your arms so it can tell you are a person.
  • If a bear follows you, stop and hold your ground. Do not run, and do not climb a tree, because both black bears and grizzly bears can climb.
  • If a grizzly or brown bear attacks, leave your pack on, lie flat on your stomach with your hands clasped behind your neck and play dead. Fight back only if the attack keeps going.
  • If a black bear attacks, do not play dead. Get into a car or building if you can, otherwise fight back, aiming at the face and muzzle.
  • Never let a bear get your food. A bear that gets food keeps coming back, which makes it dangerous for the next visitors.
  • Carry an EPA-approved bear spray made to stop aggressive bears. It is a deterrent, not a repellent, so never spray it on yourself or your gear.

Source: National Park Service[29]

From National Park Service (Yellowstone)

  • In Yellowstone, the National Park Service asks visitors to stay at least 100 yards (91 m) from bears, wolves and cougars.
  • If the animal moves closer, back away. Approaching wildlife close enough to disturb or displace it is illegal in the park.
  • Never feed wildlife. Use binoculars or a long camera lens instead of moving closer.

Source: National Park Service (Yellowstone)[30]

Questions people ask

Is the Brown Bear endangered?
It is not listed as endangered or threatened under the US Endangered Species Act in USFWS data[1]. NatureServe ranks it N3 (Vulnerable) in the United States[7].
Where does the Brown Bear live in the United States?
NatureServe lists it as native in Alaska, Idaho, Montana, Washington and Wyoming[3].
What does the Brown Bear eat?
It eats plants, fruit, fish, insects and mammals, and plant matter is a large part of its diet[31]. One estimate gives 60% other plant material, 20% fruit, 10% warm-blooded animals and 10% invertebrates[17].
How big is a Brown Bear?
NatureServe records a typical length of 213 cm (84 in) and a typical adult weight of 680 kg (1499 lb)[15][16].
How long does a Brown Bear live?
The longest recorded lifespan is 40 years, in captivity[4].

Facts and sources

  1. Brown Bear is not listed as endangered or threatened under the US Endangered Species Act in USFWS ECOS data (checked 2026-10-30). USFWS ECOS
  2. NatureServe global conservation status rank for Brown Bear: G4 (Apparently Secure). NatureServe Explorer
  3. NatureServe lists Brown Bear as native in 5 US states and territories: Alaska, Idaho, Montana, Washington, Wyoming. NatureServe Explorer
  4. Maximum recorded lifespan in AnAge: 40 years in captivity. This is a record, not a typical lifespan. AnAge
  5. Brown Bear (Ursus arctos) is a mammal in the family Ursidae, order Carnivora. NatureServe Explorer
  6. Other English names listed by NatureServe for Brown Bear: Grizzly Bear, Mexican Grizzly Bear. NatureServe Explorer
  7. NatureServe national rank in the United States: N3 (Vulnerable). NatureServe Explorer
  8. IUCN Red List category as recorded by NatureServe: Least concern. NatureServe Explorer
  9. CITES listing recorded by NatureServe: Appendix II (controls on international trade). NatureServe Explorer
  10. NatureServe estimate of total adult population (global, as a range): 100,000 to 1,000,000 individuals. NatureServe Explorer
  11. NatureServe ranks Brown Bear as extirpated or possibly extirpated (SX or SH) in: Arizona, California, Colorado, Kansas, Minnesota, North Dakota, Nebraska, New Mexico, Nevada, Oklahoma, Oregon, South Dakota, Texas, Utah. NatureServe Explorer
  12. NatureServe state ranks for Brown Bear (map and table on this page). NatureServe Explorer
  13. NatureServe notes on habitat for Brown Bear. NatureServe Explorer
  14. Habitat types NatureServe records for Brown Bear: Forest - hardwood, Forest - conifer, Forest - mixed, Woodland - hardwood, Woodland - conifer, Woodland - mixed, Shrubland/chaparral, Grassland/herbaceous, Alpine, Tundra, Riparian, Medium river, Creek,... NatureServe Explorer
  15. Typical length recorded by NatureServe: 213 cm (84 in). NatureServe Explorer
  16. Typical adult weight recorded by NatureServe: 680 kg (1499 lb). NatureServe Explorer
  17. Estimated diet composition in EltonTraits 1.0: 60% other plant material, 20% fruit, 10% warm-blooded vertebrates, 10% invertebrates. EltonTraits 1.0
  18. NatureServe notes on reproduction for Brown Bear. NatureServe Explorer
  19. Typical litter or clutch size in AnAge: 2. AnAge
  20. Gestation or incubation period in AnAge: 103 days. AnAge
  21. Age at female sexual maturity in AnAge: 1,313 days (about 3.6 years). AnAge
  22. Adult food habits recorded by NatureServe: Carnivore, Piscivore, Invertivore, Herbivore, Granivore, Frugivore. NatureServe Explorer
  23. Activity time in EltonTraits 1.0: crepuscular, diurnal. EltonTraits 1.0
  24. NatureServe migration category for Brown Bear: non-migrant, local migrant (populations can differ). NatureServe Explorer
  25. NatureServe notes on phenology for Brown Bear. NatureServe Explorer
  26. GBIF observation records of Brown Bear in the US by month (chart on this page). GBIF
  27. NPSpecies park lists recording Brown Bear as present (list on this page). NPS NPSpecies
  28. US states with the most GBIF observation records of Brown Bear: Alaska, Wyoming, Montana, California, Colorado. Record counts follow observer effort, not population size. GBIF
  29. Safety guidance from National Park Service. National Park Service
  30. Safety guidance from National Park Service (Yellowstone). National Park Service
  31. NatureServe notes on food for Brown Bear. NatureServe Explorer

Status, range and habitat come from NatureServe Explorer (CC BY 4.0) and USFWS ECOS at the snapshot date. Listings change by federal rule. State lists are where NatureServe records the species, not a promise that you will see it there. Never name a place smaller than a state. GBIF and park records count observations and checklists. They show where and when people report the species, not how many animals live there.

NatureServe. 2026. NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org. (Accessed: October 30, 2026). Licensed under CC BY 4.0; SpeciesFacts selected and summarized it.

Photo: Robert F. Tobler, CC BY-SA 4.0, via Wikimedia Commons.