Bears or Humans more Dangerous in Yellowstone Back Country?

Image of bear by Troy Nemitz

A few years ago, I held the widespread belief that in the wild, humans were far more dangerous than bears. Humans are the top predator on the planet. They routinely prey on their own. Far more humans are killed by humans than by bears.

The reality is more complex. As I researched bear attacks and the effectiveness of using handguns to stop those attacks, I found I was mistaken about the comparative danger of humans. Comparing how many people are killed by humans against how many are killed by bears is a misleading metric. There are hundreds of millions of people in North America, and somewhat less than a million bears.  About six percent of those are grizzly bears. There are about ten to fifteen thousand polar bears associated with North America. The danger of something is not represented by how many people are killed or hurt, out of the entire human population. Rather, the danger of something is more reliably measured by how many people are killed or hurt per the item in question in relation to exposure to humans.

Very few people die of drowning in the Sahara desert. To be in danger of being killed by a bear, you have to be where the bears are. It can happen in New York City, if you break into the zoo. In 1982, a man was killed by a polar bear when he climbed a series of fences to get into the bear cage after hours. An eleven year old boy was killed by bears in New York City when he sneaked into the polar bear enclosure at night, in 1987. Most of the time, most people are not in contact with bears. Lack of opportunity does not mean bears are not dangerous.

To consider how dangerous bears are, you must consider the danger level where the bears are. Fortunately, the National Park Service has kept records of  injuries and  fatalities inflicted by grizzly bears and the number of visitor days in Yellowstone park. The National Park Service site had these helpful numbers for the risk of being injured or killed by bears in the park.

Type of Recreational Activity:

Risk of Grizzly Bear Attack
Remain in developed areas, roadsides, and boardwalks: 1 in 25.1 million visits

Camp in roadside campgrounds: 1 in 22.8 million overnight stays

Camp in the backcountry: 1 in 1.4 million overnight stays

Travel in the backcountry: 1 in 232,000 person travel days

All park activities combined: 1 in 2.7 million visits

If you stay away from bears (in developed areas) the risk of injury by bear is only 1 in 25.1 million visits.

If you go where the bears are (travel in the back country), the risks increase 100 fold to 1 in 232,000 travel days. If you were in the back country for 1,000 days, or about five years (bears are only active about 200 days a year), your risk of injury by bear increases to 1 in 232! Deaths were about 15% of the injuries, or about 1 in 1600.

Make it a career, or about 30 years, the risk of injury by bear is roughly 1 in 39, with the chance of a fatality 1 in 265.  Increase the years to 78, the typical life expectancy in the United States, and the chances of being injured becomes 1 in 16, with chances of a fatality 1 in 102.

To put the risk in perspective, the lifetime risk of death by car accident in the United States is about 1 in 114.

The time you spend traveling in the back country in Yellowstone park, you have about the same chance of dying from bear attack, as you have of dying in a car accident, if you spend the time in the rest of the United States.

Bear attacks in bear country are a significant risk; about the same as car accidents in the rest of the United States.  The risk can be reduced through preventative measures and the use of safety equipment.

Wearing a personal firearm in bear country is similar to buckling your seat belt while driving.

Many bears are prevented from injuring humans, because the human was armed.

Timothy Treadwell spent a lot of time with bears. He did not consider bears a serious threat. He and his girlfriend, Amie Hugenard, were killed and eaten.

Phil Shoemaker guided people in Alaska for 33 years. For years he disparaged people who carried pistols to defend against bear attacks. In July, 2016, he used a 9 mm Smith & Wesson  pistol to defend his clients from a serious bear attack. He no longer derides people for carrying pistols to defend against bears.

The United States Geological Survey maintains an interesting collection of data on grizzly bear mortality in the Greater Yellowstone Ecological system (GYE).

I looked at the data for 2017. In 2017, there were 56 grizzly bear deaths recorded, out of a population of 690.  The grizzly bear population has been growing steadily since 1975, when they were listed as endangered. There were about 136 bears in the GYE in 1975. No fatal bear attacks on humans were recorded in the GYE in 2017.

In 2017, Of the approximate population of 690 grizzly bears, 56 died. Of the 56 recorded bear mortalities, 19 were killed in self defense by humans. 16 were killed by government bear management because they had proven to be a threat to humans and human property. 35 bears out of a population of 690, for one year, were a threat to human lives and human property. That is over five percent of grizzly bears in 2017.

Three bears were killed in road accidents and two were killed because of mistaken identity during black bear hunts. Natural causes (non human) accounted for seven bear deaths. Two of those were from other bears. Six bears died of unknown causes; three bear deaths were still under investigation.  Of the known causes of bear deaths (47) 35 were caused by bear-human conflicts, of which 19 were self defense killings  by humans.

Grizzly bears are an extremely dangerous species to humans. Humans are extremely dangerous to bears, if the human is attacked.

The indications are that numerous bears are killed in self defense for every person killed by a bear.

From the national park service nps.org:

5. Reducing conflicts with people is the key to grizzly conservation. Employing best practices for safety in bear country doesn’t just protect people, but the welfare of animals as well. When bears kill people or damage property, bears lose.

The aggravated assault rate plus the murder rate for humans would be the comparable number to grizzly bear attacks. In 2016, for the United States, the aggravated assault rate was 248 per 100,000. The homicide rate was about 5 per hundred thousand. That would be a comparable rate of 253 per hundred thousand, or about .253%.  On an individual basis, the grizzly bears in the GYE are more than 20 times as dangerous as humans. One in 20 is involved in a serious assault in a given year. Roughly 1 in 400 humans is victimized in a serious assault in a given year in the United States.  Humans are far less dangerous in Yellowstone National Park. Career criminals don’t seen to spend much time in Yellowstone. If they do, they are on vacation and seldom attack other people.

If you encounter a human stranger far from police or other humans, you should be wary. If you encounter a bear under the same circumstances, you should be many times as wary. If the bear does not run, prepare to defend yourself.

If you encounter a bear in the wild, your chances of injury or death have multiplied by orders of magnitude. They have become much, much higher than being struck by lightning. There have been only two deaths from lightning in Yellowstone park in the last hundred years, to compare with the seven deaths caused by bears. Neither of the lightning deaths occurred in the back country.