Is Killing Yellowstone's Bison Necessary?

Yellowstone National Park is expected to kill nearly 900 of its bison this winter, marking the largest cull since 2008. Although laws state that culls are needed to manage growing populations and protect Montana's livestock for infectious diseases bison may be carrying, conservationists argue this large-scale slaughter is unnecessary and brutal -- they have filed a lawsuit claiming that the public has a right to witness this year's controversial cull.