At the Department of Energy’s Fermi National Accelerator Laboratory, where groundbreaking particle physics research meets the pioneering spirit of the American prairie, a beloved spring tradition continues. Today, two baby bison arrived, marking the beginning of calving season at the laboratory.
The two calves were born on April 21, healthy and strong, joining Fermilab’s storied herd that has been a part of the lab since 1969. Cleo Garcia, Fermilab’s herdsman, estimates that around 20 calves will be born this season.
“Our herd is doing well,” Garcia said. “Each year, we monitor the cows closely to estimate how many calves we’ll have. It’s always exciting to see the first birth of the season.”
The herd currently consists of 23 cows, two bulls, and three yearlings born in 2024. Fermilab rotates its bulls every five to seven years to maintain genetic diversity, ensuring that the herd remains close to 100% pure American bison. Genetic testing in 2015 confirmed that the herd contains little to no cattle genes — a significant achievement.
When bison calves are born, they sport a distinctive cinnamon-colored coat, which darkens to brown as they grow. At birth, they weigh between 40 and 70 pounds, but by six months, they can reach 300 to 350 pounds. Despite their rapid growth, the young bison remain close to their protective mothers, especially in the first few weeks.
“One of the most exciting moments is when a calf takes its first steps,” Garcia said. “Sometimes, within just a few minutes of being born, they’re already up and walking around — it’s incredible to see.”
Calving season generally continues through June, however last year a calf was born in September. Visitors are encouraged to stop by to see the newest members of the herd. Fermilab’s outdoor public areas are open daily from dawn to dusk, offering a chance to witness these iconic animals in their natural habitat. Visitors 18 and older must present REAL ID-compliant identification to enter the laboratory grounds. To accommodate people unable to visit in person, the Fermilab bison cam provides a virtual view of the herd from anywhere in the world.
“Seeing new life arrive on the prairie is one of the best parts of the year,” Garcia said.
Visit Fermilab’s Hours and public access webpage for information and requirements for visiting the lab, and come celebrate the arrival of spring along with Fermilab’s newest additions.
Fermi National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
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