The Bison: An Iconic Species of the West

Bison vs. Buffalo: What’s in a Name?

In the United States, "bison" and "buffalo" are used interchangeably to describe the same iconic animal: the North American Bison. While both terms are widely accepted, they carry different historical and scientific meanings.

The Cultural History

The term "buffalo" dates back to the early 1600s. French fur trappers, upon seeing these massive herds, called them les boeufs (meaning "oxen" or "beef"). Over time, the name evolved into "buffalo." The term stuck because the animals shared a passing resemblance to the Asian Water Buffalo and African Cape Buffalo—species the Europeans had previously encountered.

The Scientific Reality

In 1758, the species was formally classified as Bison bison. Because "buffalo" had already been the common name for over a century, the term "American Buffalo" was adopted to distinguish our native species from those on other continents.

Today, bison remains the precise scientific and industry name, while buffalo remains a cherished term deeply rooted in American history, culture, and tradition. At the Rocky Mountain Bison Association, we utilize both terms to honor both scientific clarity and our Western heritage.

Fast Facts: The Power of the Bison

As North America's largest land mammal, the bison is a marvel of biological engineering and resilience.

  • Family: Member of the bovine family (related to wild oxen and cattle).

  • Dietary Habits: Obligate herbivores and ruminants (animals that "chew cud" to efficiently process grasses).

  • Surprising Agility: Despite their size, they are elite athletes—able to jump 6-foot fences from a standstill and reach speeds of 40 mph.

  • Social Structure: Highly social animals that live in organized family groups.

  • Winter Resilience: They possess incredibly thick hides and grow a dense, woolly coat that allows them to thrive in sub-zero Rocky Mountain winters.

  • Strong Swimmers: Bison are naturally buoyant and capable of swimming across large rivers.

  • Keystone Species: Their grazing habits and movement are essential for maintaining healthy, diverse grassland ecosystems.

Buffalo, Bison rolling in dirt, walking in a pasture, mom and calf together.

Understanding the Species

There are two recognized subspecies of the American Bison: the Plains Bison (Bison bison bison) and the Wood Bison (Bison bison athabascae). While they share a close genetic lineage, they have evolved distinct physical characteristics:

  • Wood Bison: Typically found at higher latitudes (such as Canada and Alaska), they are the larger of the two. They are characterized by a darker coat, a higher body weight, and a pronounced hump located further forward—directly above the front legs.

  • Plains Bison: The subspecies most common in the Rocky Mountain region, they are slightly smaller with a hump positioned directly over the shoulders.

Lifespan & Characteristics

In the wild, bison typically live to be 15 to 20 years old, though individuals in managed herds have been known to exceed 30 years. A unique characteristic of the species is their permanent horns. Unlike deer or elk that shed antlers, both bulls and cows grow a single set of horns that remain for their entire lives. If a horn is broken, it will not grow back, though the remaining horn structure will continue to thicken as the animal matures.

The Great American Recovery

Prior to 1830, an estimated 30 million bison roamed the North American continent, serving as the keystone species of the vast grasslands. However, following westward expansion and the reports of explorers like Lewis and Clark, unregulated hunting nearly led to their extinction. By the late 1800s, fewer than 1,000 bison remained in all of North America.

The Rebirth of the Herd

Today, the population has rebounded to nearly 500,000 head in North America, and that number continues to climb. This remarkable recovery—one of the greatest in conservation history—is largely due to the efforts of private ranchers. By creating a sustainable market for bison meat, ranchers have provided the economic incentive to return these animals to their native landscapes.

Bison Today

Significant private holdings, such as those managed by Ted Turner— one of the largest individual landholder in North America with over 50,000 bison—work alongside public herds in national parks and tribal lands to ensure the species' future. In recognition of its cultural and ecological importance, the bison was officially named the National Mammal of the United States in 2016.

A mature North American bison bull showcasing the distinctive shoulder hump and dark wooly coat.

Bulls (Males)

Bison bulls are massive animals, standing up to 6 feet at the shoulder. During the 'rut' (breeding season), their deep, guttural bellows can be heard for miles.

An adult bison cow in a grassland setting, demonstrating the permanent horn structure common to the species.

Cows (Females)

Bison cows are fiercely protective mothers. While smaller than bulls, they are remarkably agile and lead the herd's daily movements.

A young bison calf, commonly known as a 'red calf,' standing in a pasture shortly after birth.

Calf (Baby)

Known affectionately as 'red calves' due to their bright orange coats at birth, bison calves are born ready to move, often standing and walking within minutes.