Origins of the Bison at Tallgrass Prairie Preserve

The Tallgrass Prairie bison herd was started with 300 animals donated by the Ken-Ada Ranch north of Bartlesville in the fall of 1993, and christened the Christina Adams Bison Herd (for the daughter of the Ken-Ada Ranch owners, Kenneth and Dianna Adams). The herd has since grown, more or less according to schedule. The target size is a summer herd of 2,600, including calves, with an over-wintering herd of 1,950, in a 23,000 acre fiire-bison unit.

All heifer calves are vaccinated against brucellosis and all incoming animals are tested for brucellosis and tuberculosis and quarantined before admission to the herd. Even though there is no substantiated evidence of bison to cattle transmission of brucellosis, great pains are taken to ensure the herd remains brucellosis free. During the annual roundup all keeper animals are vaccinated for several bovine diseases and treated for external and internal parasites.

Genetic mixing is controlled by the importation and culling of breeding bulls. Bulls have been obtained from a number of sources, including: Custer State Park, SD; Cross Ranch Preserve, ND (TNC); Fort Niobrara NWR, NE; Fort Robinson State Park, NE; KS Parks & Wildlife, Garden City Herd, KS; Ken-Ada Ranch, OK; Maxwell Game Refuge, KS; National Bison Range, MT; Niobrara Valley Preserve, NE (TNC), Samuel H. Ordway Memorial Prairie, SD (TNC); Sedgwick County Zoo, KS; and Wichita Mountains NWR, OK.

Bulls are sold at 6-7 years of age, since after this they tend to become more aggressive and dangerous. Cows are sold at 10-12 years of age. They are still productive through their early twenties but their sale value is higher as teenagers. Also, the older cows are less physically fit for withstanding the rigors of roundup.

The herd receives no supplemental feeding, but, because the animals are in a restricted range, salt with trace minerals is provided. Water is available in creeks and ponds.

For research and record-keeping purposes, each individual bison in the herd is identified with an ear-tag transponder. This tag is read by holding a wand near the animal's head; the wand transmits the tag's data to a portable computer. Each transponder transmits a unique number, which is then assigned to that particular animal. Some of the information tracked includes the animal's sex, origin, age, weight, pregnancy status, and general health. Due to the lack of a 'standard tag', the tags have been changed several times. Recently the International Standards Organization (ISO) published a standard for herd animal tags. During the 2002 roundup the tags were replaced with ISO-standard e-tags, which should simplify this aspect of the herd management.

More About Bison

A Historical Perspective
Great herds of bison once roamed North America between the Appalachian Mountains and the Rocky Mountains.

Tallgrass Bison Herd Size
The original herd of 300 bison at Tallgrass Prairie Preserve has grown to the optimum over-wintered size of about 2,100, which is based on the available range.

Bison Vital Statistics
Bison can weigh as much as 2000 pounds, stand over six feet tall and live as long a 40 years.

Bison Behavior
Bison are grazers who prefer grasses to other prairie plants, such as wildflowers.

Bison Personality
Bison are ordinarily mild-mannered, even dull, animals but can be aggressive.

Bison Facts



Stay Updated

Learn about the places you love and find out how you can help by signing up for Nature eNews.

I'm already on the list Read our privacy policy

Thank you for joining our online community!

We'll be in touch soon with more Nature Conservancy news, updates, and exciting stories.