A bear canister for storing your food is required when camping in Desolation, and we came prepared with an Ursack, made of a specially designed bear-proof material that is lightweight and easier to fit in your pack than a big canister. The point of it is to hang the bag high in a tree and on a branch far enough from the main trunk so the bear can’t reach it from the ground or from on the tree. It came with instructions on tying a bear-proof knot. Wait…bears can untie knots?!