{
  "slug": "shark-attack",
  "question": "What are the odds of being killed by a shark?",
  "category": "animal",
  "no_reliable_estimate": false,
  "perceived": {
    "description": "Shark attacks are a cultural archetype for catastrophic risk — a single vivid film, reinforced by occasional summer headlines, keeps \"eaten by a shark\" near the top of many people's fear lists despite being one of the rarest causes of death on Earth.\n",
    "rough_estimate": "34.6% of US adults report being afraid or very afraid of sharks (Chapman Survey 2024)",
    "kind": "survey",
    "survey_source": {
      "title": "Chapman University Survey of American Fears, Wave 10 — Complete List of Fears 2024",
      "publisher": "Chapman University",
      "url": "https://www.chapman.edu/wilkinson/research-centers/babbie-center/_files/2024-csaf-fears-high-to-low.pdf",
      "year": 2024
    }
  },
  "native": {
    "display": "~1 unprovoked shark attack fatality per year, United States (of ~8 worldwide)",
    "numerator": 1,
    "denominator": 335000000,
    "unit": "per year",
    "population": "US total population"
  },
  "normalized": {
    "lifetime_us_adult": 1.76e-7,
    "display": "1 in ~5,700,000 lifetime (US adult)",
    "log_value": -6.75,
    "assumptions": "The International Shark Attack File reports a 5-year average (2020-2024) of 8 unprovoked fatal shark attacks per year worldwide, with the United States accounting for approximately one of those fatalities in a typical year. The native rate uses the US-specific subset (~1 death/year among ~335 million US residents) since the normalized figure is a US adult lifetime risk. Annual rate: 1/335,000,000 ≈ 2.99 × 10⁻⁹. Compounded over 59 years of remaining adult life: 1 − (1 − 2.99 × 10⁻⁹)⁵⁹ ≈ 1.76 × 10⁻⁷, i.e. roughly 1 in 5,700,000. The uncertainty band reflects years with zero US deaths (low) and occasional years with 2-3 (high).\n",
    "uncertainty": {
      "low": 9e-8,
      "high": 5e-7
    },
    "scope": "us_adult_lifetime"
  },
  "sources": [
    {
      "url": "https://www.floridamuseum.ufl.edu/shark-attacks/yearly-worldwide-summary/",
      "title": "International Shark Attack File — Yearly Worldwide Summary",
      "publisher": "Florida Museum of Natural History, University of Florida",
      "source_type": "reputable_reference",
      "statistic": "5-year average (2020-2024) of 8 unprovoked fatal shark attacks per year worldwide; 2025 saw 9 fatalities from 65 unprovoked bites",
      "excerpt": "\"This number is also in line with the most recent five-year annual global average of eight unprovoked fatalities per year. [...] The 2025 worldwide total of 65 confirmed unprovoked cases is in line with the most recent five-year (2020-2024) average of 61 incidents annually.\"\n",
      "source_date": "2026-01-01",
      "source_accessed": "2026-04-11",
      "archive_url": "https://web.archive.org/web/20260411093742/https://www.floridamuseum.ufl.edu/shark-attacks/yearly-worldwide-summary/",
      "calculation_notes": "ISAF reports a 5-year average (2020-2024) of ~8 unprovoked fatal attacks per year worldwide, with the US accounting for ~1 in a typical year. The US-specific annual rate (~1/335M) is compounded over 59 years for normalized lifetime risk: 1 − (1 − 2.99e-9)^59 ≈ 1.76e-7.\n",
      "independence_note": "ISAF maintains its own international shark-attack case register, built from voluntary reports, media scanning, and expert verification. Entirely independent of CDC's ICD-10 death-certificate pipeline — the two describe overlapping events through different collection mechanisms.\n"
    },
    {
      "url": "https://wisqars.cdc.gov/",
      "title": "WISQARS — Web-based Injury Statistics Query and Reporting System",
      "publisher": "US Centers for Disease Control and Prevention (CDC)",
      "source_type": "govt_report",
      "statistic": "WISQARS query tool for fatal and nonfatal injury data; ICD-10 coding does not isolate shark attacks from broader marine-animal contact (W56)",
      "excerpt": "\"WISQARS is an interactive, online collection of analysis tools for fatal, nonfatal, and cost of injury data.\" [Note: WISQARS is a query tool, not a report. ICD-10 code W56 covers all marine-animal contact and does not distinguish shark attacks from other marine encounters. Individual query results are not quotable as static text.]\n",
      "source_date": "2023-12-01",
      "source_accessed": "2026-04-11",
      "archive_url": "https://web.archive.org/web/20260410040543/https://wisqars.cdc.gov/",
      "calculation_notes": "WISQARS data confirms that ICD-10 W56 (contact with marine animal) deaths in the US are very rare. The coding does not isolate sharks from other marine animals, but the low total is consistent with the ISAF figure of ~1 US shark fatality per year.\n",
      "independence_note": "ISAF and CDC draw from different case collections (voluntary international reporting vs ICD-coded death certificates), so this counts as meaningfully independent corroboration.\n"
    }
  ],
  "comparison_anchors": [
    {
      "label": "Death by falling coconut (lifetime, global)",
      "lifetime_us_adult": 2e-10
    },
    {
      "label": "Death by bee/wasp sting (lifetime, US)",
      "lifetime_us_adult": 0.0001267
    },
    {
      "label": "Death by lightning (lifetime, US)",
      "lifetime_us_adult": 0.00000354
    }
  ],
  "personal_factor_multipliers": [
    {
      "factor": "frequent surfer (100+ sessions/year)",
      "multiplier": 50,
      "notes": "surfers account for ~50% of unprovoked attacks; frequent ocean users have dramatically higher exposure"
    },
    {
      "factor": "Florida Atlantic coast resident, regular ocean swimmer",
      "multiplier": 5,
      "notes": "Florida leads US in unprovoked attacks; regular swimmers have higher encounter rates"
    },
    {
      "factor": "landlocked state resident",
      "multiplier": 0.01,
      "notes": "near-zero ocean exposure eliminates encounter risk"
    },
    {
      "factor": "spearfishing with bleeding catch in open water",
      "multiplier": 15,
      "notes": "ISAF data identify blood and fish scent from spearfishing as a strong olfactory attractant for sharks; spearfishers are over-represented in provoked and unprovoked attack records relative to their share of ocean users"
    },
    {
      "factor": "ocean entry at dawn or dusk in known shark habitat",
      "multiplier": 5,
      "notes": "ISAF guidance and peer-reviewed shark-behavior literature document elevated shark feeding activity at crepuscular hours (dawn and dusk), increasing encounter probability for surfers and swimmers who enter the water at those times"
    }
  ],
  "short_label": "Shark attack",
  "myth_framing": "overrated",
  "outcome_severity": "fatal",
  "exposure_pattern": "acute",
  "outcome_type": "death",
  "valence": "negative",
  "caveats": "This is a population-level figure over the entire US adult population. Your actual risk is essentially zero unless you spend meaningful time in waters known for large apex shark species; surfers in certain regions face higher per-hour exposure but still tiny absolute lifetime numbers.\n",
  "quality_score": {
    "d1": 4,
    "d2": 4,
    "d3": 5,
    "d4": 4,
    "d5": 4,
    "d6": 4,
    "d7": 5,
    "d8": 3,
    "avg": 4.125,
    "scored_by": "claude-code-8d",
    "scored_at": "2026-05-25",
    "methodology_version": "1.2"
  },
  "reviewer": "likelier-seed",
  "last_reviewed": "2026-04-11",
  "reviewed": true,
  "generated_at": "2026-04-11",
  "image": {
    "alt": "A single stylized shark fin silhouette against a calm horizontal water line, 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/shark-attack"
}