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• Position: Your Life - Plains bison's cross breeding with cattle

Plains bison are an iconic symbol of the U.S. on everything from coins to state flags. Scientists are exploring how their cross-breeding with domestic cattle in the late 1800s still may have unwanted effects on modern populations of the species. The plains bison are an iconic symbol of rugged individualism and the will to survive," notes James Derr, professor of veterinary pathology at Texas A&M University, College Station. "The population crash and the spectacular recovery over the last 125 years is a classic example of the resilience of this species and the success of science-based wildlife conservation."

Plains bison once numbered in the tens of millions, but were driven to the brink of extinction in the late 1880s during the U.S.'s westward expansion. A small population of wild bison survived in Yellowstone National Park, while five herds remained in the hands of private ranchers. It is estimated that less than 100 surviving bison became the common ancestors of today's herds.

In some of these privately held herds, bison were crossed with domesticated cattle in an attempt to introduce the hardy bison traits into beef-producing animals. While this effort failed to produce new and improved beef breeds, some hybrids...