Bear canister at a glance
- Typical capacity
- About 5 to 7 days of food, solo
- Store
- All food, trash and scented items
- Place
- About 100 ft from camp, untethered
What the design has to defeat
The design problem is that bears are strong, dextrous and extremely motivated. A canister answers it with hard-sided walls, smooth rounded sides that give no purchase for teeth or claws, and a lid that needs a coin, a tool or a specific sequence of moves that bear paws can't perform.
Where they are mandatory
Where they're required, they're required. Several national parks and wilderness areas mandate an approved canister for overnight trips, and the approved list is set by the individual unit, not by the canister maker. Rangers do check, and in some places you can be turned around at the trailhead. Always check the specific park or forest you're visiting before you go, because the rules differ between neighbouring units and they change.
Why they are worth carrying anyway
They're also just effective, which is worth remembering where they aren't required. Hanging food properly is genuinely difficult, needs the right tree, and fails often enough that many land managers stopped recommending it. A canister works every time, on any ground, including above treeline where hanging isn't an option at all.
How much food fits in one
Roughly 100 cubic inches per person per day is the working figure, so a common 700 cubic inch canister holds about six or seven days for one person. That assumes reasonably dense food and some effort in packing; the same days of bulky food will not fit.
Everything scented goes in, not just food: toothpaste, sunscreen, lip balm, wrappers, the ziplock the salami was in. Planning canister space around meals alone is how people end up with toiletries in the tent, which is exactly the habit the regulation exists to break.
Packing and placing one
Repackage out of boxes and into bags before you leave, which typically doubles what fits. Put the days you will eat last at the bottom. Anything with sharp corners goes in the middle so it does not stop the lid closing.
At night, set it on flat ground well away from your tent, commonly a hundred feet or more, and away from water and from any slope or cliff a bear could roll it down. Do not tie anything to it: a rope gives a bear a handle, and it is the one modification that reliably defeats the design.
What this means when you're choosing
- Whether the specific park approves that exact model, checked on the park's own site
- Volume against your trip length, since a week of food for two is a lot of canister
- How the lid opens, because a fiddly one is much worse at 6am than it is in the shop
Bear canister vs Ursack
| Bear canister | Ursack | |
|---|---|---|
| Weight | Typically 2 to 3 lb | Around 8 oz |
| Where it is accepted | Widely, and often mandated | Only where explicitly listed, which is far fewer places |
| Packing | Rigid, awkward, and doubles as a seat | Packs flat empty, moulds to the load |
| Contents afterwards | Intact | Crushed, even when the bag holds |
Which to pick: A canister wherever one is required, which is not negotiable. An Ursack where it is explicitly allowed and the two and a half pounds matter to you.
The common mistake
Tying it to a tree
Canisters are meant to be left loose on flat ground. Tethering one gives a bear leverage to smash it against rock, and some land managers explicitly prohibit attaching anything to them.
Common questions
Where do I have to use a bear canister?
That depends entirely on the unit you're visiting. Several national parks and wilderness areas require them for overnight trips, and each publishes its own approved list, so check the specific park or forest before your trip.
What goes in a bear canister?
Food, trash, and anything with a scent, which includes toothpaste, sunscreen, lip balm, medication and the wrappers you've already emptied. If it smells like anything at all, it goes in.
Where this is defined
- Certified bear-resistant products list, Interagency Grizzly Bear Committee