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  • Sara Thompson

Where Big, Beautiful Bison Roam

By Sara Thompson

Special to the Enterprise

Image credit: Yellowstone National Park, obtained from Wikimedia Commons

The American bison is not only the United States’ national mammal, they are also North America’s largest mammal. They grow over six feet tall and can be over eleven feet long, weighing in between 900-2500 lbs. when fully grown. Bison almost went extinct in the late 19th century from hunting and mass slaughters, but conservation efforts have risen the population and bison can be found in national parks, wildlife refuges, Native American lands, and private ranches in all 50 states.

Bison are herbivores, grazing on grasses and leafy plants for up to eleven hours in a day. During the winter, their large heads and necks allow them to clear snow for foraging. Despite their size, bison can sprint up to 35 miles per hour and are very agile, being able to spin quickly and jump fences, and are considered powerful swimmers. Being the largest mammal, their predators are also large. Preyed upon by cougars, grizzly bears, coyotes, grey wolves, and humans, the latter two are more likely to hunt healthy adults, where the former three hunts primarily calves, sick or wounded individuals, or scavenge from other animals. A bison’s best defense is its herd by working together to fend off predators, but when alone its size and pointed horns are also formidable weapons.

The bison’s earliest relative is believed to have evolved in Asia between 2-3 million years ago. Migration to North America can be traced around 400,000 years ago by a now extinct species of bison whose horns measured nearly nine feet from tip to tip! The horns of extant bison measure around two feet in length. Bison can live between 10-20 years. Bison females, or cows, only birth one calf per year, between the months of March and May. At birth, bison calves can weigh up to 70lbs, with larger females birthing larger calves. The hair on bison calves is a reddish orange. As they grow, their hair changes into the better known dark brown color.

Even though they are related to cattle and can hybridize, bison are wild animals and can be unpredictable. Despite multiple warnings people are injured each year in national parks by getting too close to the animals. As with all wild animals, appreciate these large, majestic beasts from a safe distance.

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