CHEYENNE, Wyo. (WKOW) -- Wild plains bison are no longer listed as a threatened species under the Endangered Species Act.
The U.S. Fish and Wildlife Service announced Wednesday that two people who petitioned to protect the bison in 2009 did not provide sufficient data to support the continuation of the study of threats to bison.
Bison were once North America's largest terrestrial mammal, numbering in the tens of millions. By the late 1800s, people had killed off almost all of them.
Bison now number about 400,000, with 20,500 of them protected and maintained for conservation.
The conservation herds are present in 10 states, including Arizona, Kansas, Minnesota, Missouri, Nebraska, South Dakota, Texas, Utah, Wisconsin and Wyoming.