The American black bear (Ursus americanus) is North America's smallest and most common species of bear. Black bears are omnivores, with their diets varying greatly depending on the season. Black bears typically live in largely forested areas, but do leave forests in search of food. Sometimes they become attracted to human communities because of the immediate availability of food. The American black bear is listed by the IUCN as Least Concern, due to the species' widespread distribution and a large global population estimated to be twice that of all other bear species combined. American Black Bears often mark trees with their claws to show dominance in an area. Dominance is determined by the highest claw mark found on the tree. This behavior is common to many species of bears found in The United States and Canada.