Bear-resistant food storage container
Encyclopedia
Backpacking (wilderness)
Backpacking combines the activities of hiking and camping for an overnight stay in backcountry wilderness...
to protect their food from theft by bear
Bear
Bears are mammals of the family Ursidae. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern...
s. Bear canisters are seeing increased popularity in areas where bears have become habituated
Habituation
Habituation can be defined as a process or as a procedure. As a process it is defined as a decrease in an elicited behavior resulting from the repeated presentation of an eliciting stimulus...
to human presence, and are required in some regions such as Yosemite National Park
Yosemite National Park
Yosemite National Park is a United States National Park spanning eastern portions of Tuolumne, Mariposa and Madera counties in east central California, United States. The park covers an area of and reaches across the western slopes of the Sierra Nevada mountain chain...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
A bear canister typically weighs between 2-4 lb (1-2 kg), and has a storage capacity of 400 - 900 in³ (6 - 15 liters). The actual capacity in number of days of hiking
Hiking
Hiking is an outdoor activity which consists of walking in natural environments, often in mountainous or other scenic terrain. People often hike on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide. The health benefits of different types of hiking...
food stored will vary with the appetite of the hiker
Hiking
Hiking is an outdoor activity which consists of walking in natural environments, often in mountainous or other scenic terrain. People often hike on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide. The health benefits of different types of hiking...
, the selection of food, and the skill in which it is packed, but a 700 in³ canister will likely hold up to a week's worth of food for the average hiker.
Construction
Hard-sided bear cans employ such materials as polycarbonatePolycarbonate
PolycarbonatePhysical PropertiesDensity 1.20–1.22 g/cm3Abbe number 34.0Refractive index 1.584–1.586FlammabilityV0-V2Limiting oxygen index25–27%Water absorption – Equilibrium0.16–0.35%Water absorption – over 24 hours0.1%...
, ABS
Acrylonitrile butadiene styrene
Acrylonitrile butadiene styrene is a common thermoplastic. Its melting point is approximately 105 °C ....
plastic, carbon fiber
Carbon fiber
Carbon fiber, alternatively graphite fiber, carbon graphite or CF, is a material consisting of fibers about 5–10 μm in diameter and composed mostly of carbon atoms. The carbon atoms are bonded together in crystals that are more or less aligned parallel to the long axis of the fiber...
, and aluminum in their construction. An effective canister must resist both the tremendous strength and high intelligence of an attacking animal. Most containers are too large for a bear to simply pick up and carry away.
The lid
Lid (container)
A lid, also known as a cap, is part of a container, and serves as the cover or seal, usually one that completely closes the object.-History:...
of a canister is usually recessed in order to prevent it getting pried off, and tool
Tool
A tool is a device that can be used to produce an item or achieve a task, but that is not consumed in the process. Informally the word is also used to describe a procedure or process with a specific purpose. Tools that are used in particular fields or activities may have different designations such...
use, or at least an advanced degree of motor skill
Motor skill
A motor skill is a learned sequence of movements that combine to produce a smooth, efficient action in order to master a particular task. The development of motor skill occurs in the motor cortex, the region of the cerebral cortex that controls voluntary muscle groups.- Development of motor skills...
s, is required to remove it. Contrary to some beliefs, many bear canisters do not contain 'o' rings that block the scent from escaping the container.
At least one model of soft-sided "bear bag" is made from Spectra (UHMWPE) fabric. While a soft-sided container may prevent a bear from eating
Eating
Eating is the ingestion of food to provide for all organisms their nutritional needs, particularly for energy and growth. Animals and other heterotrophs must eat in order to survive: carnivores eat other animals, herbivores eat plants, omnivores consume a mixture of both plant and animal matter,...
its contents, the food inside is likely to be reduced to purée
Purée
Purée and mash are general terms for cooked food, usually vegetables or legumes, that have been ground, pressed, blended, and/or sieved to the consistency of a soft creamy paste or thick liquid. Purées of specific foods are often known by specific names, e.g., mashed potatoes or apple sauce...
in the attempt. A newer model comes with an aluminum stiffener that protects the contents more effectively than the bag alone.
Regulations
A small number of national parkNational park
A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...
s and national forests require backcountry
Wilderness
Wilderness or wildland is a natural environment on Earth that has not been significantly modified by human activity. It may also be defined as: "The most intact, undisturbed wild natural areas left on our planet—those last truly wild places that humans do not control and have not developed with...
visitors to carry approved food storage containers. Backpackers who ignore this policy may face fines, property impoundment, or eviction from the wilderness. Ranger
Park ranger
A park ranger or forest ranger is a person entrusted with protecting and preserving parklands – national, state, provincial, or local parks. Different countries use different names for the position. Ranger is the favored term in the United States, Canada, and the United Kingdom. Within the United...
s may stop hikers and require them to produce their containers for inspection.
Approval
The Sierra Interagency Black Bear Group (SIBBG) and the Interagency Grizzly Bear Committee regulate the approval of food storage containers in the parts of the western United States. Containers effective against the American black bearAmerican black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...
s in the Sierra Nevada may not be effective against the grizzly bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...
s found elsewhere.
The SIBBG first conducts visual inspection and various structural tests, then containers are filled with food and left in the cages of captive black bears in a zoo
Zoo
A zoological garden, zoological park, menagerie, or zoo is a facility in which animals are confined within enclosures, displayed to the public, and in which they may also be bred....
in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. If the canister survives the zoo test, it is then conditionally approved. Full approval is only given after three months of successful field tests by users.
Bear bagging
A common alternative method is bear bagging, wherein items attractive to a bear such as foodFood
Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals...
or other perishables are placed in a bag and then raised into the air using a rope — out of reach of a bear. The rationale is that bears, being unable to reach the food, will be less drawn to campsites and pose less of a threat to campers
Camping
Camping is an outdoor recreational activity. The participants leave urban areas, their home region, or civilization and enjoy nature while spending one or several nights outdoors, usually at a campsite. Camping may involve the use of a tent, caravan, motorhome, cabin, a primitive structure, or no...
and their equipment.
Lightweight nylon stuff sacks are often used for bear bags, but they can be made simply of a large enough square or rectangular piece of cloth or tarp
Tarpaulin
A tarpaulin, colloquially tarp, is a large sheet of strong, flexible, water-resistant or waterproof material, often cloth such as canvas or polyester coated with urethane, or made of plastics such as polyethylene. In some places such as Australia, and in military slang, a tarp may be known as a...
with the food items placed in the center of the tarp and the corners brought up and tied around with rope
Rope
A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...
. The rope is then used to tie the bag in the air where it cannot be reached from the ground or from a tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
by a bear. Often this is done by tying another length of rope tightly between two trees or other tall objects. In problem areas, a bear bag should be at least 12 feet (3.5 m) high and 10 feet (3 m) from any vertical support. The counterbalance method, Marrison system, and the Pacific Crest Trail method are a few different techniques to use when hanging a bear bag.
In areas where trash cannot be burned (much of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and especially during dry seasons) and no fortified trash
Waste
Waste is unwanted or useless materials. In biology, waste is any of the many unwanted substances or toxins that are expelled from living organisms, metabolic waste; such as urea, sweat or feces. Litter is waste which has been disposed of improperly...
containers are available, trash may also be raised in a separate bear bag to keep the food smells from attracting bears.
In severe problem areas for bears, such as a majority of Yosemite National Park, bear bagging is ineffective and has been banned.
Product failure
Yellow-Yellow, a wild 125-pound black bearAmerican black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...
in the Adirondacks near North Elba, New York
North Elba, New York
North Elba is a town in Essex County, New York, United States. The population was 8,661 at the 2000 census. The town is named after the island of Elba.North Elba is on the western edge of the county...
, has figured out how to open several models of the BearVault, an approved container. Other bears there have reportedly also learned the skill. As a result, the manufacturer discourages use of the BearVault in the bears' territory, hence defeating its purpose.