Part of a bison herd maintained by the Blackfeet Nation on a private reserve in Montana. Madison Stevens, CC BY-NC-ND Bison are political animals. A federal decision to revoke grazing leases for bison on public lands on the rolling plains of eastern Montana is the latest manifestation of long-standing contention. The largest land animal in North America, bison are considered a “keystone” species, meaning they have high ecological and cultural importance. The May 2026 decision represents a signif