Photo copyright Gary Fua

It’s that exciting time of the year again, the time when bison calves are born on the prairie. On the morning of Monday, April 23, we spotted the first bison calf of the season! The calf was standing alongside her mother, nursing. With this furry little development, let’s take a moment to review some of the things we learned last year about bison…

Bison were brought to Kankakee Sands in October of 2016 to help us manage the prairie. Since that time, they have been grazing and wallowing and doing all the great things that bison do on the prairie, including breeding.

Bison typically breed in August and September. Female bison, called cows, have a gestation period of approximately nine months. So, calves are usually born in April and May. Last year, eleven calves were born at Kankakee Sands. It has been thrilling to watch the young calves grow and develop over the past year.

With 14 mature cows in the herd this year, we can expect anywhere from 1 to 14 more calves to be born this spring. (Cows typically give birth to one calf per year; twins are rare.)

When it is time to give birth, cows will often move away from the herd and settle down in the prairie. After birthing, the female will return with the calf to the herd. However, the calves routinely lie down and hide in the prairie grasses, making them difficult to see.

Bison calves are born with their eyes open and can stand within minutes of being born. Calves are able to run when they are just hours old. It’s a handy skill for a creature born onto a prairie with wolves, which historically would have been the case. (Wolves no longer roam the prairies of Newton County.)

Calves are born with fur that is red or tan in color. Due to the reddish hues of their fur, bison calves are often referred to as “red dogs” or “cinnamons.” As they get older, their fur will darken to shades of brown.

The little red dogs weigh 40 to 50 pounds at birth, ultimately reaching 800 to 1200 pounds if they are a female and 1700 to 2000 pounds if they are male.

Just like all mammals, bison calves nurse. They begin eating vegetation when they are as a young as week old. Calves are fully weaned from their mother’s milk within a few months.  

We eagerly await the other calves that will be born this spring at Kankakee Sands. These calves are the next generation of bison that will assist us in managing the prairies of Kankakee Sands.

Come celebrate the birth of the bison calves with us! Visit the Bison Viewing Area at Kankakee Sands, open from 7 am to dusk every day of the year, and share the excitement. Hoorah!


The Nature Conservancy’s Kankakee Sands is an 8,300-acre prairie and savanna habitat in Northwest Indiana, open every day of the year for public enjoyment.  For more information about Kankakee Sands, visit or call the office at 219-285-2184.