A permit is required to hike the JMT, which can be obtained from the national park or forest where the hiker begins the hike, and is available 168 days in advance. This single permit is valid for the entire hike. Permit reservations can be hard to obtain for JMT thru-hikers, but a portion of permits are reserved for walk-ins. The Whitney Portal end of the JMT has a lottery for wilderness permits, and hikers starting in Yosemite face competition with other backpackers simply wanting to camp overnight while hiking Half Dome or to Tuolumne Meadows. Backpackers entering the Sierra backcountry on multi-day trips are generally required to carry their food in approved hard-sided storage containers known as bear canisters to protect their food and other scented items from theft by black bears, which are common in the region.