The North American Bison

What It Covers

North American bison evolved from Pleistocene megafauna, shaped Great Plains ecosystems for millennia, were reduced from 60 million to under 1,000 by the 1880s, and recovered to roughly 400,000 through coordinated conservation efforts.

Key Questions Answered

• •Ecological engineering: Bison reshape prairie landscapes through four distinct mechanisms — plowing snow with their heads, aerating soil with hooves, dispersing wildflower seeds via their coats, and creating 10–15 foot wallows that become micro-ecosystems supporting germination and biodiversity across the Great Plains.
• •Grazing selectivity: Unlike cattle, bison graze grass to several inches rather than the root, then migrate away for months, allowing full recovery. This selective pattern increases photosynthesis by improving light availability and reducing plant competition, creating measurable quilt-like patterns visible across the plains.
• •Deliberate extermination: The 19th-century bison collapse was partly a calculated federal policy. Eliminating bison destroyed the foundation of Plains tribes' nomadic existence — food, shelter, tools, and spiritual life — accelerating forced relocation onto reservations without requiring direct military confrontation.
• •Conservation blueprint: Taxidermist William Hornaday and Theodore Roosevelt rebuilt bison from 85 free-range individuals in 1905 by combining zoo protection, federal land designation, state laws, and reintroduction to Yellowstone, where 25 genetically pure bison became the nucleus of today's wild herds.