Bison

Bison at a glance

Need to know

• Bison are the heaviest land animals in both North America and Europe.
• The American bison population rebounded from fewer than 600 individuals in 1900 to over half a million today.
• Both American and European bison once ranged from the United States to the far reaches of Eurasia.
• Bison can run at speeds up to 56 km/h (35 mph).
• European bison, or wisent, went extinct in the wild after World War I and have been reintroduced entirely from captive populations.
• Bison wallowing creates microhabitats that benefit many prairie species.

About the Bison

Bison are iconic large herbivores that once roamed in vast herds across the grasslands, woodlands, and steppes of the Northern Hemisphere. Renowned for their massive size, muscular frames, and rugged, humped shoulders, they are the heaviest land mammals in both North America and Europe. Two species survive today: the American bison and the European bison, both having narrowly escaped extinction due to overhunting and habitat loss in the last two centuries.

Despite their recovery through conservation efforts, wild bison remain threatened by genetic bottlenecks, disease, habitat fragmentation, and hybridization with domestic cattle. They play a critical ecological role as keystone species, influencing plant diversity, soil health, and the habitats of countless other animals through their grazing and wallowing behaviors.

Physical characteristics

Size: 2.1 to 3.5 meters in length; 1.5 to 2 meters high at the shoulder. Weight: 450 to 1270 kg (varies by species and sex). Lifespan: 15-20 years in the wild, up to 25 years in captivity.

• Massive humped shoulders
• Large head with short, curved horns
• Dense, dark brown to black shaggy fur (especially on the forequarters)
• Short, slender tails with tufted ends
• Sharp, black hooves

Notable species

• American Bison (Bison bison) — Near Threatened. Grasslands, prairies, open savannas, and lightly wooded areas Regions: Great Plains, Rocky Mountains, Canadian Prairies, Yellowstone region, Alaska, Midwestern United States.
• European Bison (Bison bonasus) — Near Threatened. Mixed woodlands and temperate broadleaf forests Regions: Białowieża Forest, Carpathian Mountains, Caucasus Mountains, Poland, Belarus, Ukraine.
• Steppe Bison (Extinct) (Bison priscus) — Extinct. Pleistocene steppe-tundra Regions: Siberia, Alaska, Yukon, Northern Eurasia.
• Wood Bison (subspecies) (Bison bison athabascae) — Near Threatened. Boreal forests, meadows, and peatlands Regions: Northwest Territories, Northern Alberta, British Columbia, Yukon, Alaska.

Habitat and range

Original range: Great Plains and woodlands of North America (American bison); temperate forests and open woodlands of Europe (European bison); steppe-tundra for extinct steppe bison

Current distribution: Wild American bison are now mainly limited to protected parks, reserves, and private lands in North America; European bison have been reintroduced to select forests in Europe; wood bison inhabit northern boreal wilderness; small introduced populations exist elsewhere for conservation.

Preferred environments: Prairies, Open grasslands, Wooded meadows, Boreal forest edges, Temperate broadleaf forests

Regions: Great Plains, Yellowstone region, Canadian Prairies, Northern Alberta, Northwest Territories, Białowieża Forest, Carpathian Mountains, Caucasus Mountains, Eastern Europe, Yukon, Midwestern United States

Where to see Bison

• Yellowstone National Park (USA) — May to September. Easiest to spot where herds graze along roads and valleys, but always observe from a safe distance.
• Białowieża National Park (Poland) — Late winter through early spring. Best chance to see free-ranging European bison, particularly in snowy clearings.
• Wood Buffalo National Park (Canada) — Summer months. Protected wood bison populations congregate near wetlands and meadows.

Behavior and diet

Diet: Grazers feeding mainly on grasses, sedges, and forbs; occasionally eat twigs, leaves, and bark, especially in winter.

Social structure: Highly social, forming herds led by dominant females (matriarchs); males may form bachelor groups or roam singly, especially during the rut.

Communication: Communicate via grunts, bellows, snorts, and body language including pawing, head shakes, and posturing.

• Wallowing in dust or mud for parasite removal and temperature regulation
• Seasonal migrations in search of fresh grazing grounds
• Head-to-head sparring between bulls during breeding season
• Using their heads to sweep snow aside while foraging in winter

Interactions with other animals

• Gray wolf (predator): Wolves prey on bison calves and occasionally adults, especially in winter or when herds are weakened.
• Cattle (competitive): Compete for grazing land; risk of hybridization and transmission of diseases like brucellosis.
• Grassland birds (symbiotic): Benefit from habitat created by bison wallows and grazing patterns.

Conservation

IUCN Red List status: Near Threatened

Threats

• Habitat loss and fragmentation
• Historical overhunting
• Genetic bottleneck and low genetic diversity
• Hybridization with domestic cattle
• Diseases such as brucellosis and bovine tuberculosis

Conservation efforts

• Reintroduction projects in national parks and reserves
• Strict legal protection and anti-poaching enforcement
• Conservation breeding programs
• Genetic monitoring to prevent hybridization

How to help

• Support bison conservation organizations
• Visit parks and reserves that protect wild bison
• Advocate for prairie and woodland habitat preservation
• Learn and share accurate information about bison ecology and history
• Participate in citizen science projects monitoring bison movements

Bison facts for kids

Bison are giant, furry animals with big humps on their backs and two sharp horns. They travel in herds and used to roam in huge groups across prairies and forests, but now need our help to survive. You can see bison in places like Yellowstone Park and wild forests in Europe.

• Bison are so strong, they can run as fast as a car in the city—up to 56 km/h!
• Baby bison are called calves, and they have reddish fur when born.
• Bison roll in dirt to get rid of itching and keep themselves cool.
• A group of bison is called a herd.
• Bison can jump over fences that are more than two meters tall!

Did you know? Did you know? Bison are North America's largest land animal, and their giant herds once made the ground shake when they ran!

Watch & learn

• Yellowstone Bison: Icon of the American West — National Geographic. This documentary explores the life cycle, behavior, and ecological importance of wild Bison in Yellowstone National Park, offering stunning footage and expert insights into their role in North America.
• The Winter Struggle: Bison’s Survival Story — BBC Earth. BBC Earth's high-quality feature showcases how Bison endure brutal winters, follow migratory instincts, and shape the prairie ecosystem, with mesmerizing close-ups and natural history commentary.
• Bison: The Giants of the Grassland — Smithsonian Channel. Smithsonian Channel’s documentary delivers a detailed look at Bison herds, their social behaviors, and historic comeback from near extinction, with authoritative narration and unique footage.
• Battle of the Bison: Epic Showdowns on the Prairie — PBS Nature. This captivating PBS Nature segment focuses on dramatic bison fights during the rutting season, and the crucial role these mammals play in prairie restoration and ecosystem balance.
• American Bison: The Untold Comeback Story — Wildlife Conservation Society. Follow the American Bison’s journey from near extinction to their reintroduction into the wild, supported by the Wildlife Conservation Society, with a focus on conservation and science.