Click here to hear a bear roar. Natural History of Black Bears Black bears are the smallest American bears, and the most common. They are the only bears found in the wild in California. Although the grizzly bear is the state mammal, it has been extinct in California since 1922. Black bears are usually nocturnal, but can be active during the day.
Bears are strong, agile, and quick.
They swim and climb trees well. A bear can run 30 miles per hour in short bursts. Bears eat a wide variety of foods. Bears will dig up underground wasp nests to eat the insects, nest and all. They are extremely hungry when they emerge from their winter dormancy period in the spring and will often strip the bark off trees to eat the sugary cambium layer.