Prehistoric bears, such as the short-faced bear and Arctodus simus, roamed North America during the Pleistocene epoch. These bears were significantly larger than modern species, with some standing over 12 feet tall when on their hind legs. They adapted to various environments, from forests to open grasslands, and were omnivorous, feeding on plants, fruits, and small animals. The cave bear, another notable prehistoric species, lived in Europe and Asia. It primarily inhabited caves, which provided shelter and protection. Fossil evidence suggests that these bears went extinct around 24,000 years ago, likely due to climate change and competition with early humans for resources.