Bison were killed with such success that they came close to extinction by the early part of the 20th century. The species was saved from being wiped out by wildlife managers in Yellowstone, who protected a small herd and allowed them to repopulate at the Buffalo Ranch in Yellowstone’s Lamar Valley. There are now some 4,600 free-roaming bison in the Greater Yellowstone region. The American bison was named our country’s national mammal in 2016.