Bears are large, robust mammals in the Ursidae family. They have short tails and show size differences between sexes, with males being larger. Mostly solitary except during mating or when raising young, bears can be active day or night and have a strong sense of smell. Despite their size, they are skilled runners, climbers, and swimmers. They use shelters like caves or logs as dens, especially during winter hibernation, which can last up to 100 days.
Bears in northern regions, such as the American black bear and the grizzly bear, undergo hibernation during the winter. In this state, their metabolism slows significantly, body temperature drops slightly, and heart rate decreases from around 55 to just 9 beats per minute. Throughout hibernation, bears typically do not wake and can go without eating, drinking, urinating, or defecating. If they have stored enough fat, their muscles remain healthy, and they meet their protein needs by recycling waste urea. Notably, female bears give birth during hibernation and briefly awaken during the birthing process.
Bear species are divided into three subfamilies, each with distinct dietary patterns. The Ailuropodinae subfamily includes only the giant panda, which is mostly herbivorous and feeds primarily on bamboo. Tremarctinae consists of the spectacled bear, an omnivorous species that eats a mix of fruits, vegetation, and small animals. The largest subfamily, Ursinae, includes six species with varied diets. Among them, the polar bear is mostly carnivorous, relying heavily on seals and other marine life, while the brown bear, American black bear, Asiatic black bear, sloth bear, and sun bear are all omnivorous, consuming a wide range of foods depending on their environment.
Bears have long held cultural significance in art, literature, mythology, and folklore. The image of the protective mother bear was common across North America and Eurasia. In many Native American cultures, bears symbolize rebirth due to their hibernation cycle. Bears were often linked with shamans, believed to predict the future or transform into bears. Evidence of prehistoric bear worship exists, particularly in early Chinese, Ainu, Finnish, Siberian, and Korean traditions. The Celtic goddess Artio and the Greek goddess Artemis were both associated with bears. The constellations Ursa Major and Ursa Minor, named in ancient times, reflect the bear's symbolic presence in the sky and are tied to ancient myths like the Cosmic Hunt.