The Rationale
As we open the 2025 Isle Royale backpacking season, new food storage regulations are in place for the park. These new rules were precipitated by the presence of a lone wolf or wolves in the eastern campgrounds and in Rock Harbor itself, apparently drawn by available human food.
Anytime wildlife become acclimated to human food, they risk (1) malnourishment because human food does not provide required nutrients for non-human species and (2) starvation during the months when humans are not present to willfully or unintentionally serve as a food source for these predators.
To prevent acclimation of wolves to humans and any potentially negative interactions, the park service must act to disrupt scavenging by wolves and prevent opportunities for wolves to engage in scavenging by removing the possibilities of available human food sources. This initiative is done in the best interest of keeping the island and its inhabitants in natural balance.
Further, with wolves coming into high-use areas of the island and expecting humans to serve as sources of food, these wild animals may become aggressive in their attempts to acquire human food when it is not readily available. Any altercation between wolves and humans could be a disaster for both.
The new food storage rule is one of the several measures the park service is taking to reduce the potential for wolves lingering in high-traffic areas where their natural predation behaviors would be disrupted and supplanted with scavenging behaviors.
The Food Storage Rules
In a nutshell and according to the new rules, food and trash should be stored in a Bear -Resistant container, whether that is a bear cannister or a bear bag. You may not leave food unattended, and you must secure food against animals in the food storage lockers or by hanging it in an approved container when you are not present to monitor your food supply.
Any bear-resistant storage system you use must be on the list of containers approved by the Interagency Grizzley Bear Committee (IGBC) to guarantee compliance with the ISRO 2025 regulations.
There are pros and cons of each type of storage in light of their properties and with regard to the storage requirements. Regardless of which storage system you choose, within the container, food and trash need to be segregated into separate storage bags to prevent cross contamination.
A common choice, bear cannisters are heavier than bear bags and difficult to hang. They will likely need to be secured to a tree trunk or log in lieu of hanging. Small canisters will weigh in at about 2 lbs. and can be sufficient for short excursions, perhaps up to five days. For excursions of a week or ten days, a larger canister is needed or two canisters may be carried, which adds up to an additional 2 lbs. Also the bear canisters do not collapse as their contents is used up, so it will always take the same amount of space in the pack.
A bear-resistant bear bag will adjust for shorter and longer hikes by virtue of its ability to collapse. Bear bags can be hung or attached to a tree trunk, depending on the needs of the environment and the nature of the predator. For black bears, for example, a bag hung over a branch and away from the trunk of a tree is important as black bears climb trees. Grizzly bears do not, so hanging the bag high enough against the trunk and out of reach of a grizzly is sufficient. Given that wolves don’t climb, the height of the hang would seem the salient point.
To be effective against bears, wolves, foxes, pine martins, and the like, the bear bags need to be scent proof. If the animals can’t smell the food, they don’t know that it’s in the bag (unless you contaminate the outside by touching food and then touching the bag without washing your hands). To keep the trash and the food stored separately, you will need two scent-proof bags to use inside the bear bag, just as you do with the bear canister.
Not all bear bags are the same either. Bear bags that are not interwoven with Kevlar or another reinforcing fiber will not be able to resist small teeth, like those of pine martins and fox, even while they will resist large teeth, such as those of bears or wolves. In areas such as Isle Royale, you will want to protect your food against small and large predators.
The rules say that you should not keep your food storage device in your tent, so you must put your food outside where critters are active in the night. If you must store your food outside the food storage lockers located in most campsites this year, you will need the Kevlar-reinforced type bag, for pine martins and squirrels climb trees and down the rope that you use to hang your bear-resistant bag.
There are many choices and brands of bear sacks and canisters, with the canisters at the heavier weight. The other IGBC-approved bags we researched were similar in price and weight to the brand we have chosen. As per that manufacturer’s website, they were out of stock so we could not test the product or make them available.
Our Choices
We choose the UrSak Major (7.6 oz.) which holds 10 liters or the Kelvar reinforced UrSak AllMitey which holds 10 liters, both with the OpSak liners. When we know we are hiking only on the east end or in well-used campsites, we choose the UrSak Major XL (8.8 oz.) which holds 15 liters and is a few ounces lighter than the AllMitey (9.5 oz.)–ounces are everything in backpacking. This bag is sufficient for 10-day excursions for one person.
Evaluated by the IGBC, UrSak is approved for use on Isle Royale National Park, an approval visible on the UrSak website.
Where there is no food storage locker at the campsite, we recommend the UrSak AllMitey at 10 liters for short excursions or when a resupply is possible and the UrSak Grizzly (13.8 oz.) which holds 20 liters for longer excursions where a resupply cannot be arranged.
The manufacturer provides a printable guide to ensure proper usage, including how to tie and secure the bags and do’s and don’ts to keep your food secure.
The UrSak is broadly approved at National parks across the US. There are restrictions in some areas, where aluminum liners are needed for approval. They are not required for use on Isle Royale National Park.
At our shop in Copper Harbor, we rent the UrSak AllMitey and the UrSak Grizzly because of the overall protection each provides, preventing any concerns for critters or wolves making off with or getting into your food. Of course, the OpSak liners are necessary, too, to contain odors. We also offer the bear-resistant UrSak Major 10 liters and Major XL and the bear- and critter-resistant UrSak AllMitey and AllMitey Grizzly for sale along with the OpSaks to contain odors.