Black bears (Ursus americanus) can be found as far south as northern Mexico and well into Canada and Alaska. One study estimated that there were 750,000 to 900,000 black bears distributed across North America, and their numbers have been growing. A recent study in the Journal of Wildlife Management documented 59 fatal black bear attacks, resulting in 63 human deaths, in the United States and Canada from 1900 through 2009. And the scientists learned that many of our assumptions about bear dangers are wrong. The most important finding is that it is lone, hungry males—not mothers with young—who are most often the killers. Some advice from the researchers on avoiding a fatal attack:

Related Content Louisiana's Bears Are Making a Comeback

1 ) Travel in groups of three or more. Fatal attacks were more common when people traveled singly or in pairs. Larger groups are likely louder, and a bear may find them more intimidating.

2 ) Learn to recognize signs that bears are in the area.

3 ) Keep food and garbage away from bears. Food or garbage was present in 38 percent of the documented fatal black bear attacks, and the scent may have attracted the bears. In addition, the scientists speculate the presence of food may make the bears more aggressive, thus increasing the possibility of an attack.

4 ) Carry bear spray (which has capsaicin, the chemical that makes chili peppers hot) if you’re going to be in bear territory. No one who has been killed by a black bear in the past was carrying bear spray with them. That doesn’t mean that the spray is guaranteed to fight off an attacking bear, but it could help.

5 ) Learn to recognize the behavior of a black bear that is considering you for its next meal. These bears silently stalk their prey, sometimes for hours, before quickly rushing to attack.

6 ) A black bear that is stalking you may be deterred by aggressive actions, such as shouting, spraying it with bear spray or hitting it with rocks, sticks or even fists. Avoid harassing bears that are just going about their business, though; females seldom attack humans except when provoked by people or dogs.

7 ) Be extra careful in August, when hungry bears are filling up with high-energy foods in preparation for winter denning. Fatal attacks most often occur in this month.

8 ) Don’t assume that there’s less danger in Canada and Alaska simply because there are fewer encounters between black bears and humans. A greater proportion of fatal attacks occur in the northern parts of the black bear’s range, perhaps because these bears are less habituated to people or more food-stressed than southern bears.

Fatal attacks are not more likely among any age group or in response to any specific human activity. And this advice does not apply to other species of bears (among brown bears, for example, mama bears with young are responsible for more fatal attacks). But it’s a good reminder for anyone planning to take advantage of North America’s great outdoors this summer to prepare for any predators you might meet along your way.