{
  "slug": "bear-attack",
  "question": "What are the odds of being killed by a bear?",
  "category": "animal",
  "no_reliable_estimate": false,
  "perceived": {
    "description": "The bear is one of the classic archetypes of wild-animal danger — large, fast, occasionally predatory, and culturally locked in as the thing that might eat you in the woods. Fatal bear attacks are vivid enough to make national news whenever they happen, which keeps the felt risk running far above the recorded rate. We haven’t yet found a rigorous recent survey that isolates “fear of being killed by a bear” from the broader category of fear of large predators or the outdoors, so the perceived side of this page is marked intuition rather than survey.\n",
    "rough_estimate": "most people guess something like 1 in a few thousand lifetime",
    "kind": "intuition"
  },
  "native": {
    "display": "~1.5 fatal bear attacks per year, United States",
    "numerator": 1.5,
    "denominator": 335000000,
    "unit": "per year",
    "population": "US total population"
  },
  "normalized": {
    "lifetime_us_adult": 2.64e-7,
    "display": "1 in ~3,790,000 lifetime (US adult)",
    "log_value": -6.58,
    "assumptions": "Uses ~1.5 fatal bear attacks per year in the United States as the long-run central estimate, drawn from Gunther’s peer-reviewed Yellowstone fatality review, Bombieri et al.’s worldwide brown-bear attack compilation, and NPS-maintained park incident records, all of which converge on a US count between roughly 1 and 2 fatal incidents per year averaged over recent decades. Divided by a US population of ~335 million and compounded over 59 years of remaining adult life: 1 − (1 − 1.5/335000000)^59 ≈ 2.64 × 10^-7, i.e. ~1 in 3,790,000 lifetime. Black-bear attacks outnumber grizzly attacks in absolute US terms because black bears are roughly two orders of magnitude more numerous, not because they are more dangerous per encounter.\n",
    "uncertainty": {
      "low": 1.8e-7,
      "high": 4.5e-7
    },
    "scope": "us_adult_lifetime"
  },
  "sources": [
    {
      "url": "https://digitalcommons.usu.edu/hwi/vol16/iss3/8/",
      "title": "Bear-Caused Human Fatalities in Yellowstone National Park: Characteristics and Trends",
      "publisher": "Human-Wildlife Interactions (Utah State University) / Gunther KA",
      "source_type": "peer_reviewed",
      "statistic": "8 bear-caused human fatalities in Yellowstone over 1872-2018; per-capita risk ~1 in 26.2 million park visits; 7 of 8 by grizzlies",
      "excerpt": "\"The per capita risk of being killed by a grizzly bear was 1 fatality for every 26.2 million park visits... Seven of the 8 fatalities were caused by grizzly bears... Most fatal bear attacks involved men (75%) and small party sizes (88%)... Although the frequency of fatal bear attacks appears to have increased in recent years, the per capita risk of fatal bear attacks has declined.\"\n",
      "source_date": "2022-11-01",
      "source_accessed": "2026-04-11",
      "archive_url": "https://web.archive.org/web/20260413163612/https://digitalcommons.usu.edu/hwi/vol16/iss3/8/",
      "calculation_notes": "Gunther’s Yellowstone review gives the strongest US-specific per-visit figure we have for fatal bear encounters and anchors the upper tail of the distribution (backcountry grizzly country). The 1-in-26.2M figure applies to park visits, not US adult lifetimes; we use it as a sanity check on the national central estimate rather than as the primary number. Eight fatalities over 146 years in a single park is consistent with a nationwide count near 1-2 per year.\n",
      "independence_note": "Gunther draws on NPS park incident records; methodologically independent of the Bombieri et al. worldwide compilation below, which is built from media surveillance and national wildlife-agency reports.\n"
    },
    {
      "url": "https://www.nature.com/articles/s41598-019-44341-w",
      "title": "Brown bear attacks on humans: a worldwide perspective",
      "publisher": "Scientific Reports (Nature) / Bombieri, Naves, Penteriani et al.",
      "source_type": "peer_reviewed",
      "statistic": "664 brown bear attacks worldwide over 2000-2015, of which 183 in North America; ~14% of attacks globally resulted in human fatality",
      "excerpt": "\"We investigated 664 brown bear attacks on humans between 2000 and 2015 across most of the range of the species... North America 183 attacks, Europe 291, East Asia 190... Half of the people were engaged in leisure activities and the main scenario was an encounter with a female with cubs... attacks have increased significantly over time and were more frequent at high bear and low human population densities.\"\n",
      "source_date": "2019-06-11",
      "source_accessed": "2026-04-11",
      "archive_url": "http://web.archive.org/web/20260415000000/https://www.nature.com/articles/s41598-019-44341-w",
      "calculation_notes": "183 brown bear attacks in North America over 16 years is ~11 per year (non-fatal and fatal combined). Applying the ~14% global fatality rate and then halving to split North America between US and Canada gives roughly 0.8 brown/grizzly bear fatalities per year in the US specifically. Adding ~0.5-1 black bear fatalities per year (from NPS and state wildlife records; black bears are much more numerous but attack far less often per encounter) lands the central estimate near 1.5 fatal bear attacks per year in the US, consistent with Gunther.\n",
      "independence_note": "Independent of Gunther and NPS incident records: Bombieri et al. compiled attacks from media surveillance and wildlife-agency reporting across multiple countries, not from park incident logs.\n"
    },
    {
      "url": "https://www.sciencedaily.com/releases/2008/03/080325171221.htm",
      "title": "Efficacy of Bear Deterrent Spray in Alaska",
      "publisher": "ScienceDaily (summarizing Smith et al. 2008, Journal of Wildlife Management)",
      "source_type": "news_article",
      "statistic": "83 bear spray incidents in Alaska 1985-2006; red pepper spray stopped undesirable bear behavior in close-range encounters; 98% of people carrying spray were uninjured",
      "excerpt": "\"Of all persons carrying sprays, 98% were uninjured by bears in close-range encounters. The study by Tom Smith and colleagues, published in the Journal of Wildlife Management, reviewed 83 bear spray incidents in Alaska from 1985 to 2006 and found that bear spray was effective at stopping undesirable bear behavior across species.\"\n",
      "source_date": "2008-03-25",
      "source_accessed": "2026-04-26",
      "archive_url": "http://web.archive.org/web/20260216085616/http://www.sciencedaily.com/releases/2008/03/080325171221.htm",
      "calculation_notes": "The species-specific effectiveness figures (92% brown bear, 90% black bear, 100% polar bear) come from the full Smith et al. 2008 paper in the Journal of Wildlife Management, not from the ScienceDaily summary. Used as the basis for the \"carries bear spray\" personal-factor multiplier. Smith & Herrero document that when bear spray was deployed in aggressive encounters, it stopped the bear’s undesirable behavior more than 90% of the time across species, and carriers were uninjured 98% of the time. A subsequent Smith paper on firearms in bear encounters found firearms perform notably worse than spray on the same outcome metric. The 10× risk reduction we use in the personal factors is a conservative reading of both.\n",
      "independence_note": "Independent dataset from the fatality reviews above: field-incident reports on deterrent use, not mortality records.\n"
    }
  ],
  "comparison_anchors": [
    {
      "label": "Death by shark attack (lifetime, US adult)",
      "lifetime_us_adult": 1.76e-7
    },
    {
      "label": "Death by lightning strike (lifetime, US)",
      "lifetime_us_adult": 0.00000354
    },
    {
      "label": "Death by venomous snake bite (lifetime, US adult)",
      "lifetime_us_adult": 0.00000113
    },
    {
      "label": "Death by dog bite or strike (lifetime, US adult)",
      "lifetime_us_adult": 0.00000704
    },
    {
      "label": "Death by bee/wasp/hornet sting (lifetime, US adult)",
      "lifetime_us_adult": 0.0001267
    },
    {
      "label": "Death in a car crash (lifetime, US)",
      "lifetime_us_adult": 0.0108
    }
  ],
  "regional_breakdown": [
    {
      "region": "Yellowstone / Glacier / Denali park visitors",
      "probability": 0.000001,
      "notes": "concentrated grizzly habitat raises per-visit encounter probability roughly 100x over US-adult baseline"
    },
    {
      "region": "Alaska resident (year-round bear range)",
      "probability": 0.000002,
      "notes": "higher year-round bear density and more outdoor activity — Alaska has the highest per-capita bear-attack rate in the US"
    },
    {
      "region": "US resident outside bear range (northeast urban, southwest)",
      "probability": 5e-8,
      "notes": "near-zero encounter probability; deaths almost always involve captive or escaped animals"
    }
  ],
  "personal_factor_multipliers": [
    {
      "factor": "backcountry hiker in grizzly range",
      "multiplier": 1000,
      "notes": "Gunther’s Yellowstone data shows the per-capita risk on multi-day backcountry trips is orders of magnitude higher than for frontcountry visitors, and the overwhelming majority of fatal US bear attacks occur in grizzly-range backcountry.\n"
    },
    {
      "factor": "carries bear spray",
      "multiplier": 0.1,
      "notes": "Smith, Herrero et al. (2008) found bear spray stopped aggressive bear behavior in >90% of encounters across species and that 98% of carriers were uninjured. The 0.1 multiplier is a conservative reading of that effect size.\n"
    },
    {
      "factor": "food stored improperly at campsite",
      "multiplier": 50,
      "notes": "Gunther attributes most Yellowstone fatalities to bears conditioned to human food or garbage; improper food storage in bear country is one of the strongest single predictors of predatory encounters.\n"
    },
    {
      "factor": "urban/suburban resident, never in bear country",
      "multiplier": 0.01,
      "notes": "Essentially zero absent travel to bear habitat; a schema-safe floor rather than literal zero because the multiplier field requires a positive number.\n"
    }
  ],
  "short_label": "Bear attack",
  "myth_framing": "overrated",
  "outcome_severity": "fatal",
  "exposure_pattern": "acute",
  "outcome_type": "death",
  "valence": "negative",
  "caveats": "This is a population-level average over all US adults. Actual risk is extraordinarily non-uniform: almost all fatal bear attacks occur in a narrow set of contexts — backcountry hiking and camping in grizzly range (Alaska, the Northern Rockies, the Greater Yellowstone Ecosystem), hunting in black bear habitat, and a small number of predatory black bear incidents in rural areas. An adult who spends no time in bear country faces effectively zero risk. A frequent Alaskan backcountry hiker faces a risk several orders of magnitude above the headline number. The number also does not travel outside North America: brown-bear-caused fatalities are more common in parts of Romania, Russia, and Turkey, per Bombieri et al., and Asiatic black bears and sloth bears account for a separate category of incidents outside our scope.\n",
  "quality_score": {
    "d1": 5,
    "d2": 5,
    "d3": 5,
    "d4": 4,
    "d5": 5,
    "d6": 5,
    "d7": 5,
    "d8": 5,
    "avg": 4.875,
    "scored_by": "claude-code-8d",
    "scored_at": "2026-05-25",
    "methodology_version": "1.2"
  },
  "reviewer": "likelier-phase-5-agent",
  "last_reviewed": "2026-04-11",
  "reviewed": true,
  "generated_at": "2026-04-11",
  "image": {
    "alt": "A single stylized bear paw print on a muted forest-floor background, flat vector illustration."
  },
  "attribution": "Likelier — https://likelier.app",
  "license": "https://creativecommons.org/licenses/by-sa/4.0/",
  "support": "https://buymeacoffee.com/kgluszczyk?via=likelier&utm_content=api-fear-single",
  "canonical_url": "https://likelier.app/bear-attack"
}