A bear box is a large bear-resistant container used to protect cached supplies from being broken into by bears or other large and determined animals in campgrounds or other outdoor environments. It serves the same purpose as a bear canister in preventing bears from gaining access to food supplies and any other items that contain smells that attract bears. More established trails in bear country may contain bear boxes at campgrounds, but many do not, which may require the use of a bear canister.
The goal in preventing bears from getting access to food is twofold, to prevent loss of food and to prevent bears from developing a taste for and becoming dependent upon human food sources. They say that a fed bear is a dead bear due to bears due to how quickly bears can crave and become dependent on human food sources.