Black Bear Attacks in the USA/Data

Exposure

Exposure Level	Number of Days	Daily Encounter Rate	Injury Given Encounter	Fatality Given Injury
1 day	1	0.00000955	0.012	0.025
10 days	10	0.00000955	0.012	0.025
100 days	100	0.00000955	0.012	0.025

The number of days represents the exposure duration in black bear country. The daily encounter rate (0.00000955 or 9.55e-6) is calculated as 1010 close encounters (estimated using similar proportion as grizzlies for black bear interactions) divided by 105.6 million visits in Yellowstone from 1991-2022, adjusted for higher black bear interactions (10,081 total). Injury given encounter (0.012) is 5 injuries divided by estimated 410 close encounters. Fatality given injury (0.025) is based on 2-2.5% mortality rate in black bear attacks. These values are constant across rows as they represent base rates.

• Grizzly bear and American black bear interactions with people in Yellowstone National Park
• A review of upper limb injuries in bear maul victims

Location

Location	Odds Ratio
Alaska	3.0
Appalachian Trail States	1.4
Other Bear-Populated States	1.0
Non-Bear Area	0.0

Odds ratios are scaled relative to other bear-populated states (baseline = 1.0) based on attack frequency and population exposure. Alaska has higher odds (3.0) due to high black bear density and 3.5 times more fatal attacks than lower 48 states. Appalachian states have moderate odds based on documented attacks.

• Fatal Black Bear Attacks in North America Over the Last 20 Years
• Bear Attacks (U.S. National Park Service)

Activity

Activity	Odds Ratio
Hiking/Camping with Dog	2.0
Hiking/Camping without Dog	1.0
Other Outdoor Activities	0.8
Indoor Activities	0.2

Odds ratios are scaled relative to hiking/camping without dog (baseline = 1.0). Hiking/camping with dog has higher odds (2.0) as over 50% of 92 black bear attacks involved dogs. Other activities have lower odds.

• Bear Attacks | Wise About Bears

Season

Season	Percentage of Attacks	Number of Months
Summer	50	3
Other Active Months	50	6
Hibernation Season	0	3

Percentage of attacks by season is estimated from North American data, with summer peak. Number of months for normalization, assuming 9 active months.

• Map Show US States With Most Bear Attacks

Precautionary Measures

Precautionary Measures	Risk Reduction Multiplier
Bear Spray and Food Storage	0.02
Bear Spray Only	0.08
Food Storage Only	0.5
No Precautions	1.0

Risk reduction multiplier represents the remaining risk after precautions. Bear spray alone reduces risk to 0.08 (92% effectiveness). Combined with food storage assumes near-complete reduction (0.02). Food storage alone reduces to 0.5.

• Bear Attacks (U.S. National Park Service)
• How Dangerous Are Black Bears?

  RiskModel: Black Bear Attacks in the USA/Data:encounter_risk
Calculation: daily_encounter_rate * exposure_days * location_odds_ratio * activity_odds_ratio * (season_percentage_attacks / season_months) / (100 / 9) * precautions_risk_reduction
    Content: Your chance of having a dangerous, close encounter with a black bear is {{One_In_X|{result}}}

  RiskModel: Black Bear Attacks in the USA/Data:injury_risk
Calculation: daily_encounter_rate * exposure_days * location_odds_ratio * activity_odds_ratio * (season_percentage_attacks / season_months) / (100 / 9) * precautions_risk_reduction * injury_given_encounter
    Content: Your chance of being injured in a black bear attack is {{One_In_X|{result}}}

  RiskModel: Black Bear Attacks in the USA/Data:fatality_risk
Calculation: daily_encounter_rate * exposure_days * location_odds_ratio * activity_odds_ratio * (season_percentage_attacks / season_months) / (100 / 9) * precautions_risk_reduction * injury_given_encounter * fatality_given_injury
    Content: Your chance of being killed in a black bear attack is {{One_In_X|{result}}}

Note that risks are averages and vary by subgroup, geography, or circumstance.

Generated by an AI assistant.