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American BisonBison bison

Every figure, record and mechanism on the American Bison profile was written from a source, and this is the working table behind it: 61 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

Smithsonian's National Zoo and Conservation Biology Institute

American bison. Smithsonian's National Zoo and Conservation Biology Institute.

The page saysNorth America's largest land animal
The source saysAmerican bison are North America's largest terrestrial animals.
The page saysup to 2,400 pounds of it
The source saysBison can weigh 1,800 to 2,400 pounds (816 to 1,088 kilograms).
The page saysGrasslands and prairie of North America
The source saysOriginally, bison were found primarily in the grasslands and prairie of North America.
The page saysnow in fragmented conservation herds across parts of Canada and the United States
The source saysToday, herds can be found in parts of Alberta ... in Canada, as well as Arizona ... in the United States. Modern conservation herds are substantially fragmented.
The page saysMainly grasses year-round, plus flowering plants, lichens, and woody plant leaves when available
The source saysBison are year round grazers. They feed primarily on grasses, but will also consume flowering plants, lichens and woody plant leaves depending upon availability.
The page saysA shaggy, heavily insulated head built to face straight into a blizzard and sweep snow off buried grass
The source saysThe shaggy head is the most heavily insulated part of their body, which has adapted as such to withstand blizzards as the animal stands facing into the wind. ... To find grass in winter they sweep their heads from side to side to clear the snow.
The page saysbacked by a 30 mph top speed
The source saysThey can reach speeds of 30 miles per hour (48 kilometers per hour).
The page saysAbout 30 miles per hour (48 km/h)
The source saysThey can reach speeds of 30 miles per hour (48 kilometers per hour).
The page saysBison also have excellent hearing and smell but poor eyesight, so an entire herd can stampede if it is startled
The source saysThey have an excellent sense of hearing and smell, but cannot see very well, so an entire herd can stampede if it is startled.
The page saysA bison's shaggy head is the most heavily insulated part of its body, adapted to withstand blizzards while the animal stands facing into the wind
The source saysThe shaggy head is the most heavily insulated part of their body, which has adapted as such to withstand blizzards as the animal stands facing into the wind.
The page saysa bison also sweeps its head side to side to clear snow off the grass buried underneath
The source saysTo find grass in winter they sweep their heads from side to side to clear the snow.
The page saysBison are North America's largest terrestrial animals
The source saysAmerican bison are North America's largest terrestrial animals.
The page saysA mature bull can reach 5.5 to 6.5 feet high at the shoulder hump and nine to 12.5 feet in length
The source saysbison are characterized by a hump over the front shoulders ... A mature bull can reach 5.5 to 6.5 feet (1.9 meters) high at the hump and nine to 12.5 feet (2.7 to 3.8 meters) in length.
The page sayscows run smaller, at about 5 feet high and 7 to 10 feet long
The source saysFemales are normally smaller, at 7 to 10 feet in length (2.2 to 3.2 meters) and 5 feet high at the hump (1.5 meters).
The page saysBison can weigh 1,800 to 2,400 pounds
The source saysBison can weigh 1,800 to 2,400 pounds (816 to 1,088 kilograms).Note: ADW (2003) gives 318 to 900 kg (700 to 1,982 lb); the current Smithsonian page wins, and the page keeps its 'can weigh'.
The page saysA bison can hit 30 miles per hour despite that bulk
The source saysThey can reach speeds of 30 miles per hour (48 kilometers per hour).Note: ADW (2003) gives 62 km/h; the current Smithsonian page wins.
The page saysits life expectancy is 15 to 20 years
The source saysThe life expectancy of American bison is 15 to 20 years
The page saysBison were once widespread from Alaska to northern Mexico
The source saysAt one time, bison were widespread from Alaska to northern Mexico
The page saysBefore 1800, bison roamed the Great Plains in vast numbers, with estimates ranging from 30 to 100 million
The source saysBefore 1800, bison roamed the Great Plains in vast numbers; estimates range from 30 to 100 million.
The page saysBy the 1890s, fewer than 1,000 were left on the continent
The source saysby the 1890s, there were fewer than 1,000 of these animals left on the continent.
The page saysThe U.S. government slaughtered many bison in an organized effort to destroy the livelihood of the Plains Indians
The source saysThe U.S. government slaughtered many bison in an organized effort to destroy the livelihood of Plains Indians.
The page saysToday around 30,000 bison live in conservation herds
The source saysconservation herds are comprised of around 30,000 individuals
The page sayswhich occupy about one percent of the original range
The source saysthe current range occupied by conservation herds has diminished to one percent of its original status.
The page saysAbout 500,000 more are raised commercially as livestock
The source saysapproximately 500,000 individuals are managed as livestock by private commercial ventures
The page saysa bison is mainly a grazer, eating mostly grasses but also flowering plants, lichens, and woody leaves when they're available
The source saysBison are year round grazers. They feed primarily on grasses, but will also consume flowering plants, lichens and woody plant leaves depending upon availability.
The page saysworking through about 1.6% of its own body weight in dry plant matter every day
The source saysOn the average, bison ingest 1.6 percent of their body mass per day of dry vegetation.
The page saysA bison's shaggy head is the most heavily insulated part of its body, and it's built to face straight into a blizzard
The source saysThe shaggy head is the most heavily insulated part of their body, which has adapted as such to withstand blizzards as the animal stands facing into the wind.
The page saysit sweeps its head side to side to clear snow off the grass buried underneath
The source saysTo find grass in winter they sweep their heads from side to side to clear the snow.
The page saysAfter a few days, the calf can keep up with the herd
The source saysAfter a few days, the calf can keep up with the herd
The page saysCalves are nursed for seven to eight months and are fully weaned by the end of their first year
The source saysCalves are nursed for seven to eight months and are fully weaned by the end of the first year.
The page saysFrom Millions to Fewer Than a Thousand
The source saysby the 1890s, there were fewer than 1,000 of these animals left on the continent.
The page saysan animal of up to 2,400 pounds
The source saysBison can weigh 1,800 to 2,400 pounds (816 to 1,088 kilograms).Note: vibe.reason; replaces 'unstoppable 2,000-pound prairie momentum', an unclaimed figure and a mood (#180)
The page saysthat can still hit 30 miles per hour
The source saysThey can reach speeds of 30 miles per hour (48 kilometers per hour).Note: vibe.reason
The page sayswhose bulls prove their fitness by charging and butting heads
The source saysMale bison display their fitness by charging and butting heads with other bulls.Note: vibe.reason

Source
02

Aune, Jørgensen & Gates 2017

Aune, Jørgensen & Gates (2017). Bison bison. The IUCN Red List of Threatened Species 2017: e.T2815A123789863.

The page saysNear Threatened
The source saysIUCN Red List category: Near Threatened (NT).

Source
03

MacNulty et al. 2014

MacNulty et al. (2014). Influence of Group Size on the Success of Wolves Hunting Bison. PLoS ONE.

The page saysa lone wolf that attacks an adult catches it only about once in 100 tries
The source saysthe very low capture rate of a single hunter (1%; Fig. 2b)Note: 1% converted to once in 100. 'Capturing' is the attack-to-capture transition, so the denominator is attacks; a capture is biting and restraining, not a kill, hence 'catches'. The adult scope is its own claim.
The page saysa lone wolf that attacks an adult
The source saysWe limited our analyses of capturing to adult bisonNote: Scope: the capture analysis, and so the 1% figure, covers adult bison only.
The page saysResearchers studying Yellowstone's wolves describe bison as the most difficult prey for wolves to kill in North America
The source sayswe use a unique dataset of observations of wolves hunting bison ... in Yellowstone National Park (YNP) ... Bison are the most difficult prey for wolves to kill in North AmericaNote: The paper states this in its introduction, citing earlier work, so the page attributes it ('describe') rather than calling it the study's finding.
The page saysthree times more difficult to kill there than elk
The source saysin YNP they are 3 times more difficult to kill than elk
The page saysbigger, more aggressive, and more likely to injure or kill a wolf that attacks it
The source saysBison are more difficult to kill than elk because they are larger, more aggressive, and more likely to injure or kill wolves that attack them
The page saysA lone wolf attacking an adult bison captures it only about 1% of the time
The source saysthe very low capture rate of a single hunter (1%; Fig. 2b)
The page saysA lone wolf attacking an adult bison
The source saysWe limited our analyses of capturing to adult bisonNote: Scope: the capture analysis covers adult bison only (FAQ 2 and body).
The page saysa bison that wolves bite and hold often escapes anyway
The source sayscapturing was not necessarily killing because bison that were bit and physically restrained by wolves often escaped
The page saysEach extra wolf in the hunting group improves its odds of a capture, up to a group of about nine to thirteen
The source saysthe threshold group size was 3–6 wolves for attacking and 9–13 wolves for capturing ... Beyond each threshold, groups size had no significant effect on success ... below these thresholds, each additional wolf improved group success by 67% ... and 40% (OR = 1.40±0.13, P <0.001) in attacking and capturing, respectively
The page saysElk are the main year-round prey for Yellowstone's wolves
The source saysin YNP they are 3 times more difficult to kill than elk ... which are the main year-round prey for Yellowstone wolves
The page saysResearchers studying those wolves describe bison as the most difficult prey for wolves to kill in North America
The source sayswe use a unique dataset of observations of wolves hunting bison ... in Yellowstone National Park (YNP) ... Bison are the most difficult prey for wolves to kill in North America
The page saysin Yellowstone they are three times harder to kill than elk
The source saysin YNP they are 3 times more difficult to kill than elk
The page saysa bison is larger, more aggressive, and more likely to injure or kill a wolf that attacks it
The source saysBison are more difficult to kill than elk because they are larger, more aggressive, and more likely to injure or kill wolves that attack them
The page saysA lone wolf attacking an adult bison manages to bite and restrain it only about 1% of the time
The source saysthe very low capture rate of a single hunter (1%; Fig. 2b)
The page saysmanages to bite and restrain it
The source saysCapture Biting and restraining prey.Note: Table 1 ethogram: the study's definition of a capture.
The page says93% less often than a lone wolf hunting elk
The source sayssolo bison capture success (0.01) was 93% less than solo elk capture success (0.14
The page saysA capture is not necessarily a kill, because bison that wolves bite and restrain often escape
The source sayscapturing was not necessarily killing because bison that were bit and physically restrained by wolves often escaped
The page saysEach extra wolf in the hunting group raises its odds of a capture, up to about nine to thirteen wolves
The source saysthe threshold group size was 3–6 wolves for attacking and 9–13 wolves for capturing ... below these thresholds, each additional wolf improved group success by 67% ... and 40% (OR = 1.40±0.13, P <0.001) in attacking and capturing, respectively
The page saysOne Wolf, One Percent
The source saysthe very low capture rate of a single hunter (1%; Fig. 2b)

Source
04

Fuhlendorf et al. 2009

Fuhlendorf et al. (2009). Pyric Herbivory: Rewilding Landscapes through the Recoupling of Fire and Grazing. Conservation Biology.

The page saysResearch at the Tallgrass Prairie Preserve in the southern Great Plains found that free-roaming bison and random fires interact across the landscape in a shifting pattern scientists call pyric herbivory, literally "grazing driven by fire," and that this interaction provides the foundation for biological diversity in North American grasslands
The source saysWe call this spatiotemporal interaction pyric herbivory (literal interpretation means grazing driven by fire). Pyric herbivory is the spatial and temporal interaction of fire and grazing, where positive and negative feedbacks promote a shifting pattern of disturbance across the landscape. We present data we collected from the Tallgrass Prairie Preserve in the southern Great Plains of North America that demonstrates that the interaction between free-roaming bison (Bison bison) and random fires promotes heterogeneity and provides the foundation for biological diversity and ecosystem function of North American and African grasslands.
The page saysFire and free-roaming bison interact across the landscape in a pattern researchers call pyric herbivory, literally "grazing driven by fire," and at the Tallgrass Prairie Preserve in the southern Great Plains that pattern was found to provide the foundation for biological diversity in North American grasslands
The source saysWe call this spatiotemporal interaction pyric herbivory (literal interpretation means grazing driven by fire). Pyric herbivory is the spatial and temporal interaction of fire and grazing, where positive and negative feedbacks promote a shifting pattern of disturbance across the landscape. We present data we collected from the Tallgrass Prairie Preserve in the southern Great Plains of North America that demonstrates that the interaction between free-roaming bison (Bison bison) and random fires promotes heterogeneity and provides the foundation for biological diversity and ecosystem function of North American and African grasslands.

Source
05

National Park Service

Bison Bellows: Birth of K-selected Species. National Park Service.

The page saysA newborn bison can stand and nurse within 30 minutes of being born, and within a couple of hours it begins to travel with the rest of the group
The source saysWithin 30 minutes of birth, newborns can stand and nurse, and within a couple of hours, they will begin to travel with the rest of the group.
The page saysby which point a calf can weigh 350 to 425 pounds
The source saysBy the time they are completely weaned of their mother's milk around 7 to 12 months, bison calves can weigh between 350 to 425 pounds (160-190 kg)

Source
06

Yellowstone National Park, U.S. National Park Service 2026

Safety. Yellowstone National Park, U.S. National Park Service, 2026.

The page saysIn Yellowstone, bison have injured more people than any other animal
The source saysBison may appear tranquil, but these large animals have injured more people in Yellowstone than any other animal.Note: body; the sentence stats.dangerLevel: High rests on (injuries, none stated fatal, so High, not Deadly) (#180)
The page saysThe park tells visitors to stay at least 25 yards (23 meters) away
The source saysKeep at least 25 yards (23 meters) from bison at all times and never approach a bison to take a photo.Note: body; stats.dangerLevel
The page saysa bison approached too closely may bluff-charge
The source saysIf approached too closely, bison may respond by bluff chargingNote: body; stats.dangerLevel ('Dangerous when cornered or provoked')

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.