ROCKY MOUNTAIN NATIONAL PARK, Colo. -- People camping overnight in Rocky Mountain National Park's backcountry will have to carry bear-proof food canisters starting Friday, May 1.

Over the past five years, park staff have seen an increase in bears seeking and accessing human food. Bear-proof trash containers have been placed in many areas of the park, particularly in frontcountry campgrounds.

Backcountry efforts have not been as successful because of non-compliance with hanging food and in some cases, difficulty for campers to hang food due to the type and availability of trees nearby, according to a statement from park officials.

In 2003, two men were seriously injured by a black bear at a designated backcountry camping site near Fern Lake in the Bear Lake area. They appeared to have followed all food storage requirements but it was likely that others who had camped in the area before were careless with their food storage. Video footage taken by a visitor in a nearby campsite on the same morning as the incident showed the same bear batting around a food canister container. He was unable to open the canister. That bear was extremely aggressive, had associated humans with food and was later killed by a park ranger.

Over the last five years, backcountry campsites in the Wild Basin area have had increased bear activity. For two summers, specific sites were closed so bears would not be successful at getting food. Last year, food canisters were required at those particular sites.

The park has a relatively small bear population. Recent research suggests there are 20 to 25 bears in the park.

“We have seen an increase in bears seeking and acquiring food. We’ve seen an increase in tents being shredded and cabins and vehicles being broken in to. We feel that this requirement is important and necessary to protect the bear population and protect visitors, without closing more backcountry campsites. The last thing park staff want to do is remove a problem bear. We feel this is a small step to take to protect the park’s vulnerable bear population; we are being proactive before it gets worse” said Mark Magnuson, chief ranger.

In the summer of 2008, backcountry users were strongly encouraged to carry food canisters and informed that the regulation would be changing in 2009 requiring the use of food canisters. The majority of backcountry campers supported the upcoming change.

The park has 267 backcountry camping sites. This new regulation will be in effect from May 1 through Oct. 31 and will be for campsites below treeline, which is the majority of sites in the park. Campers will need to supply their own canisters. They are available for rent or purchase at many sporting good shops, including shops in Estes Park and Grand Lake.

Backcountry camping in Rocky Mountain National Park requires a permit.