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Species Profile

Wood Bison

Bison bison athabascae

Boreal muscle, northern resilience.
EQRoy/Shutterstock.com

Wood Bison Distribution

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Endemic Species
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Size Comparison

Human 5'8"
Wood Bison 5 ft 9 in

Wood Bison is 1.0x the height of an average human.

A wood bison (Bison Athabascae) in Alaska

At a Glance

Wild Species
Also Known As Woods bison, Woodland bison, American bison, Bison, Buffalo, American buffalo
Diet Herbivore
Activity Cathemeral+
Lifespan 15 years
Weight 1100 lbs
Status Not Evaluated
Did You Know?

Wood bison are North America's largest land mammals; adult bulls commonly 800-1,100 kg (COSEWIC 2013; Parks Canada).

Scientific Classification

The wood bison is the largest living terrestrial mammal in North America and a northern subspecies of the American bison. It is generally larger and darker than plains bison, with a taller shoulder hump and more massive forequarters. Historically widespread in boreal regions, it now persists in managed and wild populations.

Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Artiodactyla
Family
Bovidae
Genus
Bison
Species
Bison bison

Distinguishing Features

  • Larger body and taller shoulder hump
  • More robust forequarters than hindquarters
  • Darker coat with pronounced shoulder shag
  • Typically less prominent beard than plains bison

Physical Measurements

Males and females differ in size

Height
♂ 6 ft 3 in (5 ft 11 in – 6 ft 7 in)
♀ 4 ft 12 in (4 ft 7 in – 5 ft 5 in)
Length
♂ 10 ft 2 in (9 ft 2 in – 11 ft 2 in)
♀ 9 ft 2 in (8 ft 2 in – 10 ft 2 in)
Weight
♂ 1,874 lbs (1,543 lbs – 1.1 tons)
♀ 1,003 lbs (772 lbs – 1,190 lbs)
Tail Length
♂ 1 ft 6 in (12 in – 1 ft 12 in)
♀ 1 ft 4 in (12 in – 1 ft 8 in)
Top Speed
35 mph
running

Appearance

Primary Colors
Secondary Colors
Skin Type Shaggy fur
Distinctive Features
  • Tall, forward-set shoulder hump higher than plains bison (Reynolds et al. 2003).
  • Dense wool undercoat and long guard hairs for boreal winters.
  • Dark forequarters with lighter hindquarters; strong front-to-rear contrast.
  • Less prominent beard and leg chaps than plains bison (Banfield 1974).
  • Large head and broad muzzle; pronounced dewlap under throat.
  • Short, curved horns; tips commonly turn inward toward midline.
  • Seasonal molt produces patchy shedding, especially late spring and early summer.

Sexual Dimorphism

Males are substantially larger and more massively muscled in the forequarters, with taller humps and thicker horn bases. Females are smaller and more lightly built; coloration is similar but typically less visually imposing.

♂
  • Mass 700-1,000 kg; shoulder height 1.8-2.0 m (COSEWIC 2013).
  • Broader chest and more pronounced shoulder hump than females.
  • Horn bases thicker; head appears proportionally larger and blockier.
♀
  • Mass 400-600 kg; shoulder height 1.6-1.8 m (COSEWIC 2013).
  • More slender neck and forequarters; hump less prominent.
  • Horn bases narrower; overall head profile finer than males.

Did You Know?

Wood bison are North America's largest land mammals; adult bulls commonly 800-1,100 kg (COSEWIC 2013; Parks Canada).

Shoulder height reaches about 2.0 m in large bulls, with a taller, more forward hump than plains bison (COSEWIC 2013).

Calves are born mainly May-June after ~264 days gestation; most cows first calve around age 3 (Meagher 1986; Gates et al. 2010).

Typical wild longevity is about 15-20 years; individuals can exceed 20 years under protection (Nowak 1999; COSEWIC 2013).

They specialize in boreal sedge-grass meadows and willow flats, often using forests mainly for shelter and travel (Gates et al. 2010).

A key management issue is disease risk: bovine tuberculosis and brucellosis persist in parts of the Wood Buffalo region (Nishi et al. 2006).

Unique Adaptations

  • Massive forequarters and a high shoulder hump power snow-clearing and dominance fighting during the rut (COSEWIC 2013).
  • Longer legs and a narrower, taller build than plains bison improve movement through deep boreal snow and wetlands (COSEWIC 2013).
  • Dense winter coat with insulating underfur reduces heat loss during prolonged subzero temperatures (Nowak 1999).
  • A large rumen and efficient fermentation let them extract energy from low-quality sedges, grasses, and winter-cured forage (Nowak 1999).

Interesting Behaviors

  • Rut peaks July-August: bulls bellow, wallow, and engage in head-to-head pushing contests for mating access (Gates et al. 2010).
  • Cows form nursery groups; calves "hide" briefly then follow, nursing frequently during the first weeks (Meagher 1986).
  • Winter foraging includes cratering-sweeping snow aside with head and forequarters to reach sedges and grasses (Gates et al. 2010).
  • Seasonal habitat shifts track forage: open meadows in summer, then more wooded areas for windbreaks and reduced snow exposure (Gates et al. 2010).

Cultural Significance

For many Indigenous Nations, bison are a food, hide, and tool source and a powerful symbol of reciprocity. Modern wood bison recovery often uses Indigenous-led stewardship and co-management across the boreal north.

Myths & Legends

Lakota tradition tells of White Buffalo Calf Woman, who brought the sacred pipe and teachings, linking bison with renewal and right living.

Blackfoot stories and ceremony feature the iniskim (buffalo stone), used in rituals to call bison and ensure successful communal hunts.

Niitsitapi (Blackfoot) oral histories around buffalo jumps describe luring herds over cliffs, emphasizing respect, sharing, and consequences of greed.

Pueblo Buffalo Dance traditions invoke bison as a sacred provider, performed as a prayer for rain, fertility, and community well-being.

Conservation Status

NE Not Evaluated

Has not yet been evaluated against the criteria.

Population Increasing

Protected Under

  • SARA

Life Cycle

Birth 1 calf
Lifespan 15 years

Lifespan

In the Wild
10–20 years
In Captivity
15–30 years

Reproduction

Mating System Polygyny
Social Structure Transient
Breeding Season Late July through September (rut)
Breeding Pattern Transient
Fertilization Internal Fertilization
Birth Type Internal_fertilization

During the summer rut (typically July-September), dominant bulls compete and temporarily guard ("tend") estrous cows, mating with multiple females; cow-bull associations last hours to a few days. Calves follow ~270-285 days gestation (Lott 2002; Reynolds et al.).

Behavior & Ecology

Social Herd Group: 12
Activity Cathemeral, Crepuscular
Diet Herbivore Carex sedges

Temperament

Gregarious
Wary
Maternal
Rut-aggressive

Communication

grunts
snorts
bellows
roars
scent marking
flehmen response
body postures
horning displays
wallows

Habitat

Coniferous Forest Deciduous Forest Woodland Grassland Wetland Marsh Bog River/Stream Lake +3
Terrain:
Plains Riverine Valley Hilly
Elevation: Up to 4921 ft 3 in

Ecological Role

Keystone megaherbivore maintaining boreal meadows and sedge wetlands through grazing and trampling

habitat maintenance nutrient cycling seed dispersal wetland meadow creation fuel-load reduction

Diet Details

Other Foods:
Carex sedge Graminoids Forbs Willow leaves Horsetail Aquatic plants Lichen +1

Human Interaction

Domestication Status

Wild

Never domesticated. Managed via captive breeding and translocations (e.g., Wood Buffalo NP protection, 1920s). Adult males typically 800-1,000 kg and 1.6-1.9 m at shoulder; lifespan ~15-20 years wild (COSEWIC; Govt. of Canada).

Danger Level

High
  • Charge at close range
  • Goring with horns
  • Rut aggression (Aug-Sep)
  • Maternal defense (May-Jun)
  • Vehicle collisions on roads
  • Zoonoses: brucellosis, anthrax

As a Pet

Not Suitable as Pet

Legality: Usually illegal; permits only for licensed facilities.

Care Level: Expert Only

Purchase Cost: $1,000 - $20,000
Lifetime Cost: $60,000 - $200,000

Economic Value

Uses:
Conservation Tourism Research Ranching Indigenous
Products:
  • meat
  • hides
  • viewing
  • education
  • genetics

Relationships

Ecological Equivalents 5

Animals that fill a similar ecological role in their ecosystem

Moose
Moose Alces alces Boreal megaherbivore that overlaps in riparian willow use and the use of winter yards.
Woodland caribou Rangifer tarandus caribou Northern boreal resident. Shares predator guild and winter range constraints.
Elk
Elk Cervus canadensis Large grazer-browser that uses meadows and edge habitats seasonally.
Muskox
Muskox Ovibos moschatus Cold-adapted bovid that forages on sedges and grasses and exhibits group anti-predator behavior.
Plains bison Bison bison bison Same species. Large grazer that exhibits rutting behavior, wallowing, and herd dynamics.

The Wood Bison is the Largest living, native terrestrial North American Mammal.

In March 2011, the first wood bison roamed free on American soil again for the first time in over 100 years. These animals that are the largest North American mammal, weigh about 350 pounds more than the plains bison. Wood bison live in grass and sedge meadows across British Columbia, Alberta, Manitoba, the Yukon, and Northwest Territories. A herd has been reestablished on Alaska’s Inoko Flats along the lower Yukon River. These animals are greatly affected by cold weather and significant snowfalls, which makes grazing extremely difficult.

5 Incredible Wood Bison Facts!

  • Wood bison are the largest native terrestrial land mammal in North America.
  • Wood bison may all come from 11 animals that survived in Canada.
  • A wood bison calf is red when it is born.
  • Wood bison have a distinctive upward hump at the base of their necks.
  • Wood bison form herds by sex.

Wood Bison Scientific Name

The scientific name of the wood bison is Bison bison athabascae. That is different than the plains bison that is called the Bison bison bison. There is an excellent chance that both subspecies are descended from the Bison priscus, called the steppe bison. Furthermore, around 1920 when the Canadian government moved large herds of woods and plains bison to Wood Bison National Park, the two subspecies may have interbred dramatically.

Buffalo and bison are only distantly related, even though the terms are often used interchangeably. Buffalo live in Asia and Africa while bison live in North America and Europe. Buffalo does not have humps.

Wood Bison Appearance

The wood bison is the larger of the two bison species that live in North America. This species stands about 6-feet tall and is about 10-feet long. Males weigh about 2,000 pounds when mature while females weigh about 1,200 pounds.

Wood bison have a hairy coat that gets longer in the winter. They also have longer hair on their chins, resembling a beard. These adaptations help the wood bison stay warmer in the winter.

They are much wider in the front quarter than in the back quarter. This is one of the adaptations that help the animal use its front legs to remove snow easier to get to the grass under it. They have a large hump starting at the base of their necks and sloping downward through the front quarter. This adaptation helps them move their massive head through the snow in the wintertime to graze. The head has large horns that grow straight upward.

Mature wood bison have dark-brown-to-black hair along their legs and lower body. The hair is a lighter color over the rest of their bodies, including the hump. Calves are born with red hair that turns darker as they age. Red hair is one of the adaptations that help calves blend in better to their environment before they are old enough to defend themselves.

These bison has a short tail that is usually about 3-feet long. The tail ends in strands of dark hair.

Two wild wood bison grazing in Alaska national park.

Two wild wood bison grazing in Alaska national park.

What is the Difference Between a Wood Bison and a Plains Bison?

There are many differences between a wood bison and a plains bison. The plains bison is a smaller animal. It is about 250 pounds lighter. While male wood bison stand almost 7-feet tall at their withers, male plain bison stand about a foot shorter. Additionally, wood bison grow to be about 10 feet long while plains bison is about a foot shorter. Not only is the plains bison smaller than the wood bison, but it also has a stockier appearance.

Another difference between a wood bison and a plains bison is the head. The plains bison has a rounder head with fuzzy hair on it. By comparison, the woods bison has a more pointed head with long, straight hair draping down its forehead.

Yet, another difference between the two subspecies is that the woods bison’s hump is more pointed than the plain’s bison. Furthermore, when you look at the two species from the front, you will see long strands of hair on the plain’s front legs that are missing or much less prominent on the wood bison.

When examined from the side, the cape on the plain’s bison looks like an addition to its body, similar to a little child wearing a Superman cape. Meanwhile, on the woods bison, the cape looks like part of the natural hair process. The woods bison is also a darker color than the plains bison.

Wood Bison Behavior

Females and their calves live in groups of up to 60 animals throughout the year. Bulls live in smaller herds. Bison are opportunity eaters who will cover a large territory in search of food. When the food is gone from one area, they roam to another one to find ample food. Herd size often goes up or down depending on the availability of food.

Wood Bison Habitat

Most of these bison live in captive herds. There is one captive herd in Alaska, one in Sakha Republic, Russia, and the rest are in Canada. The Canadian government considers the herds living in its country to be wild animals. The government, however, has placed restrictions on where these animals can live, so 97.4% of their original habitat is not available to them.

One herd is near Aishihik Lake, Canada. Conservation efforts in this region of the Yukon are underway to return the habitat to its original arboreal forest state.

Another herd is along the Alaska Highway Corridor near the Aline Lake area east of Liard Hotsprings in northern British Columbia. This herd tends to move along the highway while grazing on the grass along the highways’ edges.

Another herd location is near Nahanni Butte in Southwestern Northwest Territory, Canada. This is an extremely isolated area, and this herd has more water access than many of the other herds. Therefore, researchers do not believe that it moves as often or as far as many of the other herds.

A final herd was established in Canada along the Etthithun River in northeastern British Columbia. This herd has about 5,000 square acres that it moves across regularly.

Wood Bison Diet

These bison are herbivores who dine on a variety of plant life throughout the year. In the winter, about 97% of their diet is sedges. In the spring and summer months, they eat sedges and willows. The bison include lichens in their autumn diet.

Overall, these bison prefer to live in moist sedge meadows during the winter months because it is easier to secure food there. They will use their large heads and neck muscles to move snow to get tasty things to eat. During the summer months, mountain bison often move to willow savannas, where the plants provide a higher amount of crude protein. In the fall, they often live in more wooded areas where lichen is regularly available.

Especially during extremely harsh winters, it is not unusual for up to 20% of mountain bison to starve to death.

Wood Bison Predators and Threats

Man is the largest threat faced by these bison. Canada still has laws in place allowing animals who are considered nuisances to be killed.

Additionally, the proximity of the bison to domestic cattle has allowed some cattle diseases to be passed into herds. In particular, anthrax was responsible for several mountain bison deaths in Wood Bison National Park and other Northern Canada locations. In about 1963, the government killed almost 600 healthy bison to prevent the spread of the disease further, and you can still see ramifications of that act in the present herd.

Wood Bison Reproduction and Life Cycle

Most mating in these bison occurs between July and September. The female gives birth about nine months later. Calves can walk from about the time that they are born.

While females become sexually mature at about 12 months, they often wait until after 18 months to breed. Then, they give birth to one calf every 1-to-3 years. Bulls mature a little slower and often do not reach sexual maturity until they are about 24 months old. They usually do not have a chance to breed until they are about 8 years old because they must wait for stronger and older bison to die or become injured.

These bison are polygamous, with each bull often impregnating numerous cows. Often during the breeding season, a mature bull will protect young cows until they are ready to breed. Then, he will impregnate them.

Wood Bison Population

There are about 4,400 of these bison left in the world. The majority of them live in herds in Canada.

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Sources

  1. Alaska Wildlife Conservation Center / Accessed June 1, 2021
  2. Discover / Accessed June 1, 2021
  3. Alaska Public Media / Accessed June 1, 2021
  4. Canadian Science Publishing / Accessed June 1, 2021
  5. Animal Spot / Accessed June 1, 2021
  6. Alaska Department of Fish and Game / Accessed June 1, 2021
  7. Anchorage Daily News / Accessed June 1, 2021
  8. Plains Bison and the Wood Bison in Canada / Accessed June 1, 2021
  9. Northern Public Affairs / Accessed June 1, 2021
A-Z Animals Staff

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Wood Bison FAQs (Frequently Asked Questions)

There are about 4,400 wood bison left in the world. One herd of them live in Alaska and another herd lives in Russia. The remaining mountain bison live in Canada. All are in herds are managed by various governments. Many of those herds have been left to go as wild as possible while steps are still taken for supplemental feeding, medication, and herd size limiting at times.