A grizzly bear at the Bronx Zoo has put a bear-proof canister through a grueling half-hour of battering and prying. The canister, designed to hold food for backpackers, was filled with treats before it was sealed and placed in the bear enclosure. There, the canister was clawed, beaten, and stomped-on by a 700-pound bear. Fortunately, the canister stood up to the assault and remained intact despite the bears' strenuous attempts to get at the goodies inside.

Such canisters, if impenetrable to bears, are an important part of efforts to discourage bears from foraging for food around campsites and other areas inhabited by humans. Similar bear-proofing of garbage bins and dumpsters is equally important and has improved safety for humans and bears alike.

Why is it so important to minimize the chance of bears getting at food? The reasons become clear if we look at what was happening in Yellowstone National Park in the early 1960s.

Historically, Yellowstone's bears (which include both black bears and grizzly bears) fed on roots, fruit, insects, small mammals, fish, and carcasses of larger mammals killed during the cold winter months. But when human populations started visiting the Yellowstone area, garbage came with them.

The lure of waste bins and refuse dumps around park hotels was an easy temptation for the bears. They visited them with increasing regularity and in increasing numbers. At first, it was a novelty. Visitors enjoyed the opportunity to see bears up-close. But problems soon surfaced. Bear-human conflicts ever more common and there was a sharp increase in the number of property damages caused by bears. Bears even resorted to begging for food handouts along roadsides. The situation was spiraling out of control:

"Between 1931 and 1959, an average of 48 park visitors were injured by bears and an average of 138 cases of bear-caused property damage were reported each year. The high incidence of bear-caused human injuries was thought to be due to changes in bear behavior caused by the availability of human food and garbage. In short, bears were not behaving like wild bears, and the consequences to humans as well as to bears were unacceptable." ~ National Park Service Press Release.

In 1970, drastic measures were put in place, dumps within the park were closed and garbage cans were re-engineered into impenetrable bear-proof tanks. Most importantly, a strictly-enforced ban on bear feeding was put in place. It was cold-turkey for the bears that had grown used to the all-you-can-eat open dumpster culture of Yellowstone in the 1960s. But the changes proved to be a great success. Bear-human conflicts dropped significantly and the animals returned to their normal diet. Bear populations retreated from the car parks and busy roads and returned to the back country and to their proper food sources.

Find out more:

• Bear-Tested, Bear-Approved (Wildlife Conservation Society)
• View Video Clip of Bear Testing Canister (Wildlife Conservation Society)
• Yellowstone Bear History (Yellowstone Travel Guide)
• Why Use a Bear Resistant Canister? (New York Department of Environmental Conservation)