The leaves and stems have fine hollow hairs on them. If you touch these hairs, they inject formic acid, which causes irritation and stinging. The discomfort goes away after a few hours, but the plant can be avoided if you know what it looks like and where it grows. There are bears in the park. All the bears you will find in the wild in California are black bears.
Black bears have many color variations, including brown and cinnamon colored coats.
Black bears have a keen sense of smell. Although the park does not have a bear problem, it is always wise when camping in bear country to properly store food. Food should be stored out of sight in your vehicle at night. Rolling up the windows will minimize enticing food odors. Mountain Lions Mountain lions, or cougars, inhabit some areas of the park.