An up-close look at our national
mammal: the American bison

An up-close look at our national mammal: the American bison
By Tim Spitzack | Editor | July 2023

For the first time in nearly 150 years, American bison are once again roaming the prairie along the Mississippi river. Our nation’s national mammal was reintroduced to Spring Lake Park Reserve in northern Dakota County last fall and the 8-head herd has already expanded by 50% – four calves were born this spring. Today, the herd allows us to get a glimpse of what the natural prairie looked like in ages past and to observe first-hand how bison benefit the landscape.

Over the past decade, Dakota County has been working to restore about 150 acres of the reserve to its native habitat by removing invasive species and doing controlled burns to promote the growth of wildflowers and other plants. Today, the bison are lending a hand – or a hoof, as it were. They boost the ecosystem by grazing on grasses, thus giving wildflowers the chance to flourish. Their hooves embed wildflower seeds into the soil, helping promote plant growth. As wildflowers increase, they attract more pollinators, which in turn help create a healthy habitat that supports other insects and animals.

Dakota County worked with the Minnesota Bison Conservation Herd Partnership to bring the bison to Spring Lake Park Reserve last October. The partnership, which includes the Minnesota Department of Natural Resources, the Minnesota Zoo and the Zollman Zoo, seeks to establish a herd of 500 bison around the state that have no cattle genes. The Spring Lake Park project was made possible by a $560,000 Minnesota Environment and Natural Resources Trust Fund grant and about $851,000 in state bonding.

As Dakota County developed its reintroduction project, it received support from the Tribal Historical Preservation Office of the Upper Sioux Community. Bison were instrumental in the lives of Indigenous communities, who used them for food, clothing, fuel, tools and shelter. They also hold spiritual significance for Indigenous people. Millions of bison once roamed North America but were decimated by Westward Expansion. As European settlers pushed west, the bison population lost grazing ground and was hunted nearly to extinction. By the late 1880s, only a few hundred remained in the U.S.

The bison at Spring Lake Park Reserve roam free within three large fenced-in paddocks, and are periodically moved between the paddocks. The public may view the bison by hiking or biking along the Mississippi River Greenway trail through the lower park reserve at the western side of the park. Parking is available at the Fahey Trailhead at 13690 Pine Bend Trail, Rosemount.

Facts about the American bison from the U.S. Department of the Interior:

• The American bison was named the national mammal on May 9, 2016.
• Bison are the largest mammal in North America. Male bison (bulls) weigh up to 2,000 pounds and stand 6 feet tall, while females (cows) weigh up to 1,000 pounds and reach a height of 4-5 feet.
• Cows begin breeding at the age of two and have just one calf at a time. For males, the prime breeding age is six to 10 years. Bison calves weigh 30-70 pounds at birth. Most are born from late March through May and are orange-red in color, earning them the nickname “red dogs.” After a few months, their hair starts to change to dark brown and their characteristic shoulder hump and horns begin to grow.
• Bison can live up to 20 years. The average lifespan is 10-20 years.
• You can judge a bison’s mood by its tail. When it hangs down and switches naturally, the bison is calm. If the tail is standing straight up, watch out, it may be ready to charge! No matter what a bison’s tail is doing, remember that they are unpredictable and can charge at any moment.
• Bison are fast. They can run up to 35 miles per hour and are extremely agile and can spin around quickly. They can jump high fences and are strong swimmers.
• Bison wallow in the dirt to deter biting flies and help shed fur. Male bison also wallow during mating season to leave behind their scent and display their strength.
• Bison have poor eyesight but excellent senses of smell and hearing.
• Cows and calves communicate using pig-like grunts. During mating season, bulls can be heard bellowing across long distances.
• Yellowstone National Park is the only place in the U.S. where bison have lived continuously since prehistoric times. In 2021, Yellowstone’s bison population was estimated at 5,450, making it the largest bison population on public lands.