Each summer, the crowds return. In the midst of this traffic and work, nature continues. Usually, somebody will throw the critters something to eat. They do not normally attack people, but park officials warn people not to allow their children to stray without an adult nearby. Mountain lions, which are marvelous stealth hunters, prefer to strike prey that is smaller and represents an easier kill.
Campers sometimes wake up in the morning with a doe browsing through nearby vegetation.
The Miwok tribes also ate from the natural food around the valley, including mushrooms, berries, bulbs, insects, and some 40 different plants. Exotic species of plants and grasses are found throughout the valley, so don't be surprised to see the apple orchard on the east end where bears often go to feed. Park officials have begun meadow-burning projects to clear the land of invasive exotic species and allow natural grasslands to return in many places. Such burns either allow native plants more room to grow or they eliminate excess brush that would only fuel a much larger fire and endanger large trees. In general, avoid Yosemite Valley on Memorial Day, the Fourth of July, and Labor Day weekends.