Wild American bison (commonly called ‘buffalo’) once numbered in the tens of millions and roamed in herds that covered much of North America. Today, the wild population stands at just 20,000, with hundreds of thousands more fenced in on private and public lands. To keep American bison roaming free as their lands continue to disappear, the Nature Conservancy has partnered with ranchers such as Duke Phillips III to manage a wild herd at the Medano-Zapata Ranch, which extends over 100,000 acres in Colorado’s San Luis Valley. To prevent overgrazing, once a year the Medano-Zapata ranchers collect between 1,500 and 2,000 of the bison to be sold. It’s a dangerous drive – the animals are famous for their extraordinary strength and unpredictable temperament – but to the ranchers it’s worth the risk, giving them an opportunity to both protect the land and earn enough income for the rest of the year.