How burly bison bear the winter

Bison, or American buffalo, have evolved to be able to withstand harsh winters. Photo: Reidar Hahn

Amidst the backdrop of some of the world’s leading technology in particle physics, a herd of bison stand against the winter winds and falling snow at Fermilab. Although Fermilab is renowned for its scientific research, the bison—also known as American buffalo—are one of the laboratory’s main tourist attractions, and they rarely disappoint.

Even on the coldest days, when temperatures drop well below freezing, the bison will be out and about for any tourists who wish to brave the Illinois winter for a look at the 2,000-pound animals. While humans require layers of clothing to keep warm, bison evolved to withstand the cold with little more than their thick, winter fur coats.

In fact, bison have 10 times more hair per square inch than many breeds of cattle, which keeps them warm throughout the winter. They also have short eyelashes to prevent ice buildup. Such features are fitting for a wild animal that ruled the American Midwest for thousands of years, challenged only by brown bears and wolves.

Although a double row of fences keeps the Fermilab bison to certain areas, they are still wild animals, said Cleo Garcia who has helped for the last 11 years with what little maintenance the herd needs.

“On rare occasions young calves have used the barn, but the adult bison never enter because their wild nature won’t tolerate such a confined space,” Garcia said.

Obtaining liquid water and sufficient food are what Fermilab bison might fret over most during these winter months. However, Garcia provides supplemental food and keeps the herd well fed with grain and hay, and he consistently checks the heated water tanks to ensure there is a steady supply of liquid water.

At present, Fermilab is home to 23 bison. Robert Wilson, the laboratory’s first director, purchased the first animals for the grounds in 1969, and the laboratory manages the herd to maintain its population size from year to year and to ensure diversification of the gene pool. Wilson wanted to honor the heritage of the laboratory and preserve the iconic image of American prairies at Fermilab, and the bison are just one symbol that upholds his wish. They also have become a symbol for the pioneering research that takes place at the laboratory.

Learn more about the Fermilab bison.

Jessica Orwig