Bear Canister Basics
"You can't count on food being safe if you put it in a nylon sack and hang it in a tree overnight. If you've never lost food by counterbalancing [suspending 2 bags of food high on a tree branch], it's only because you're lucky, no matter how well you do it."
—Harold Werner, retired wildlife biologist (31 years) at Sequoia/Kings Canyon national parks.
Hanging food in trees is the traditional method of storing food while camping in the backcountry. The better alternative is a bear canister—a portable, hard-sided food locker.
Its purpose: Make food and scented items (toiletries and trash) totally secure from bears, raccoons, rodents and other critters that are powerfully attracted to human food.
Bear Canister Pros and Cons
Upside: Canisters offer backpackers peace of mind by providing a simple, effective way to keep human food safe from animals. They can also double as a camp stool.
Downside: They are heavy (2-3 lbs.), bulky and a tight (or insufficient) fit for all the food and scented items you aim to carry on a lengthy trip.
Canisters typically hold 3-5 days’ worth of food and toiletries for 1 person.
Required Usage in Some Parks
Use of an approved canister is mandatory in some national parks and wilderness areas. This list includes:
- Yosemite National Park (entire backcountry except a few sites where food lockers are in place)
- Sequoia/Kings Canyon National Parks (selected areas; food boxes in place in numerous locations)
- Grand Teton National Park (entire backcountry except where food lockers are in place)
- Rocky Mountain National Park (all backcountry campsites below treeline)
- North Cascades National Park (selected areas)
- Olympic National Park (selected areas)
- Denali National Park (selected units)
- Glacier Bay National Park (all treeless areas)
- Gates of the Arctic National Park (most areas)
- Inyo National Forest, eastern and central Sierra Nevada, California (selected areas)
- Eastern High Peaks Wilderness Area, Adirondack Mountains, New York (between April 1 and Nov. 30, all areas)
Contact individual park and wilderness area administrators for up-to-date information. Some parks offer a canister loaner program from their backcountry offices.
SierraWild.org, a sporadically updated website jointly operated by the National Park Service, U.S. Forest Service and Bureau of Land Management, offers bear information and an overview map of where canisters are required in California's Sierra Nevada.
Why Bear Canisters Are Useful
The counterbalance method came into vogue in the 1970s: 2 bags (stuff sacks, usually) of roughly equal weight and bulk tied together and suspended on a branch 20 or more feet off the ground at least 10 feet from the trunk. It’s a time-consuming task that is rarely simple.
How do you retrieve it? Tie a loop on one bag, and use a long stick to snag it and pull both bags down. Some people tie a long strand of fishing line to one bag; fishing line dangles almost invisibly to the ground and allows a person to reel in the stash by hand.
Where permitted, counterbalancing is still the food-storage tactic of choice if no other option is available.
Bears—intelligent, resourceful and, when it comes to human food, relentless—have found ways to defeat even a superb counterbalance. Adults, for example, will send out cubs on thin limbs to chew the cord or snap the branch.
"Once bears get introduced to human food, they get hooked," says Werner. "They will go to great lengths to find more. They'll even take up residency at 11,000 feet if there's a campsite nearby that consistently attracts people and their food."
Canister Usage Tips
In 2010, the International Journal of Wilderness published a study, “Wilderness Food Storage: Are Bear-resistant Food Storage Canisters Effective?”
Citing 3 surveys on canister usage, the authors arrived at this answer: “Canisters are extremely effective when used properly and conscientiously, but there is still room for human error, and that is the root cause of most, if not all, of the problems….compliance approaching 100% is likely necessary to avoid human-bear conflicts.”
The authors noted that in Yosemite approximately 100 wilderness bear incidents are reported annually.
Once familiarized with human food, a bear’s natural food-foraging habits are altered. Bears become increasingly aggressive in their pursuit of human treats, harassing campers in scary human-bear encounters. Such events lead to a death sentence for what are now “problem bears.” Rangers are obliged to kill such bears due to safety concerns.
Kate McCurdy is a former wildlife biologist at Yosemite and was once the park's task force leader for its bear-management program. “It was my job to kill bears that become aggressive toward humans and their food," said McCurdy, now director of the Sedgwick Reserve near Santa Barbara. "That's not something I enjoyed.