Before they used canisters, campers often stored food in bags, typically hung from cables slung between trees, which inadvertently made for one-stop shopping for bears.

“They had learned that when they saw a bag in the air, there had to be a rope someplace and they learned to bite or slice the line,” said Neil Woodworth, executive director of the Adirondack Mountain Club, a conservation and recreation group.

The number of “negative human-bear interactions,” according to the Department of Environmental Conservation  mainly incidents in which bears approached people looking for food  dropped to 61 last year in the eastern High Peaks from 374 in 2005. But, of course, there was a problem with the solution.

BearVaults, one of several canister brands, are favored by many backpackers because they are light and can be opened with bare hands; most others require a coin or screwdriver. Like other brands, BearVaults must pass the zoo test, in which bears are given a certain amount of time to try to break into a canister filled with food.

Similar to a childproof medicine bottle, the BearVault 350 and 400 models can be opened by pressing a tab that allows the camper to screw off the lid. But reports began coming in from campers a few years ago that BearVaults were being broken into. State wildlife officials began suspecting Yellow-Yellow, one of a number of bears they have tagged and tracked as a way of studying the behavior of the more than 5,000 bears roaming the Adirondacks.

In most BearVault break-ins, Yellow-Yellow’s radio collar indicated she had been in the area. Eventually, campers began spotting her from afar rifling canisters. There have been no reports of her threatening anyone.

Image Campers in the Adirondacks are warned to beware of bears. Credit... Nathaniel Brooks for The New York Times

So last year Mr. Hogan introduced the 450, a two-pound cylinder costing about $60, and a larger version, the 500, each with a second tab. On them, a camper must press in one tab, turn the lid partway, then press the second tab to remove the lid. “We thought, ‘O.K., well, one bump didn’t work so maybe two bumps will thwart her,’ ” he said.