American Bison

The American bison (Bison bison) is the largest land animal in North America and one of the most powerful symbols of the continent's natural heritage. Standing up to 1.9 meters at the shoulder and weighing up to 900 kg, bison once roamed the Great Plains in staggering numbers estimated at 30 to 60 million animals, forming one of the greatest wildlife spectacles on Earth. Hunted to near extinction in the 19th century, with fewer than 1,000 individuals remaining by 1889, the bison has become an extraordinary conservation success story, with populations now numbering around 500,000, though most are in commercial herds rather than truly wild populations. In 2016, the bison was designated the national mammal of the United States, recognizing its ecological and cultural importance.

Bison are massive, barrel-chested animals with a distinctive large head, massive shoulders, and a pronounced hump over the front quarters — unlike cattle, where fat is distributed more evenly. Both males and females carry short, curved horns that curve upward and outward from the head. Males are significantly larger than females, and both sexes have a thick, shaggy coat on the head, neck, shoulders, and forelegs that is darker and more pronounced in winter, serving as insulation against harsh prairie weather. Their hindquarters are noticeably lighter and more slender than their powerful forequarters.

Bison are highly gregarious and historically formed enormous migratory herds that followed seasonal grass growth across the plains. Modern herds are smaller but still exhibit strong herd cohesion, with females and calves forming core groups and bulls living separately or on the periphery except during the mating season. The rut occurs in July and August, when bulls engage in bellowing contests, rolling in dirt wallows, and violent clashes of heads and horns. Bison are known for their unpredictable temperament, capable of sudden explosive charges, and should never be approached in the wild.

Bison are selective grazers that preferentially consume grasses and sedges, choosing the most nutritious plant parts available. In summer, they graze on lush green grasses and forbs in meadows and along river valleys. In winter, they use their massive heads as snow plows, sweeping snow aside with side-to-side motions to expose dried grasses beneath the snow pack. A large bison can consume approximately 25 kg of plant material per day, and their digestive system, like cattle, involves rumination to extract maximum nutrition from tough grasses.

The bison rut occurs in July and August, when bulls compete intensely for mating rights through bellowing, wallowing, and direct combat. After a gestation period of approximately 285 days, cows give birth to a single calf, typically in April or May. Calves are born with a reddish-orange coat that earns them the nickname 'red dogs,' which darkens to the characteristic brown of adults within a few months. Calves are highly precocial and can stand and run within hours of birth, essential for keeping pace with the herd. They nurse for 7 to 8 months and remain with their mothers for about a year.

No animal is more deeply woven into the cultural and spiritual fabric of the Great Plains peoples than the bison. For thousands of years, Indigenous nations such as the Lakota, Comanche, Blackfoot, and dozens of others relied on bison for food, clothing, shelter, tools, and spiritual sustenance — virtually every part of the animal was used. The systematic slaughter of bison between 1870 and 1890 was a deliberate act of cultural genocide aimed at destroying this foundation. Today, tribal nations are at the forefront of bison restoration, reconnecting both the animal and the people to the prairie landscape. Bison ranching has also grown significantly, providing a sustainable meat industry.