The wood bison is the larges terrestrial mammal in North America and originally was scattered in small, non-migratory herds from northern Alberta to Alaska. Like the plains bison, hunting nearly eliminated the wood bison at the end of the 19th century, when the species' population reached an estimated low of 250. The bison has been an important element of the fauna of Alberta for nearly 10,000 years, providing sustenance and materials for many of Alberta's first human residents. Bison also provide an important source of food to wolves and other animals that scavenge their carcasses. Wood bison are considered obligate grazers, primarily consuming the grasses and sedges found in the small prairies of the boreal forest. Bison may be partially responsible for maintaining these habitats. Fire suppression, disruption of flood regimes and the disappearance of bison from northern Alberta have likely combined to result in forest encroachment and eventual loss of some of these boreal prairies.