Bison Biology- Facts About Bison

Bison Anatomy

Bison Ecology

Did you know?

Are Bison and Buffalo the same?


Bison or American Bison often called ‘buffalo” or American Buffalo. Although it’s not correct, it’s an old habit formed from the first explorers seeing them and referring to them as an Ox type animal.
See: Did you know?   

“Buffalo” is a completely different animal than Bison, people are thinking of the Water Buffalo, also called domestic water buffalo or Asian water buffalo, as a large bovid originating in the Indian subcontinent, Southeast Asia, and China. Today, it is also found in Europe, Australia, North America, South America, and some African countries.  They are known for their milk.

WE DO NOT MILK AMERICAN BISON. Water buffalo don’t have wool, they are not native here, they are usually black and have skin more like an elephant. They like the waters, where they can be the “Water Buffalo”. 


Are bison native to North America?  Yes!! Our only native grazer.

American Bison are the largest land mammal in North America. As a native species, they play a unique role in the health and diversity of the ecosystem. Bison Ecology


How many bones does a bison have? 
A bison has 213 bones and 32 teeth.  (A Beef Cow has 207 bones) Bison Anatomy


What’s the average weight of bison?

Males or bulls can weigh up to 3,000 pounds, some have weighed more, while the more common range is 1500 – 2000lbs and measure up to 6 ½ feet at the shoulder. They can easily be 9 to 11 feet long. Extremely fast and agile animals. They can run 35 miles an hour and jump a 5-foot fence flat-footed. I saw a 4-month-old calf ‘almost’ clear a 5-foot fence. Just think what they can do with all that size and speed, that with being highly intelligent. Nothing to mess with.

Females or cows are much smaller than their male counterparts. Usually weighing in at 800 to 1200lbs. Some have hit 1400lbs.  They still have horns, chaps, and capes, just not as large as the bulls. They reach a height of 4 to 5 1/2 feet at the shoulder and can be 8 feet long.

Colonel Dodge’s take on Wood or Mountain Buffalo


Wood Bison vs Plains Bison

Plains vs Woods Bison by Wes Olson
“artwork by Wes Olson”

The Plains Bison (genus: Bison, species: bison, subspecies: bison)

The Wood Bison (genus: Bison, species: bison, subspecies: athabascae).

Both Wood and Plains are BISON.




How long do bison live?

Charles Goodnight thought they lived forever.  He did believe they lived much longer than what we find today.  “No one knows how long a buffalo will live. I have had a buffalo cow more than twenty-eight years old which produced a calf.”  Charles Goodnight- 1916. They most certainly can live to their late twenties. General Lawton was 26 when he died and  Sir Donald was older than that. The average is about 20 -25 years plus.  Currently, there is a bison in Australia that is in his 30’s. (Jan 2021) Understand also, the younger deaths in bison are not from old age, I’ve heard sickness/worms, broken legs, another bison attack, etc…..then you have competing males during rut, where an older or even young bull can lose his life in the battle. 

“No one knows how long a buffalo will live. I have had a buffalo cow more than twenty-eight years old that produced a calf. ” Charles Goodnight in 1916



1905 European Bison
1905 Unkn Author European (Wisent) a lowland bison, Białowieża bison (Bison bonasus bonasus)


How much does a baby bison weigh?

Bison calves weigh 30-70 lbs at birth. Then you’ll have those that have to stand out of the herd and weigh more or less than average. We had a calf last year that weighed 27lbs. She was a tiny thing but has grown up to be as big, if not better than calves her age.




Lowland and lowland-Caucasian European bison
in the Białowieża Forest


European Bison Species
A: Białowieża bison (Bison bonasus bonasus) B: Mountain Caucasian bison (Bison bonasus caucasicus.)

Dig. 2. Differences in the structure of the head and feet of the Bison bonasus bonasus (A) and the Caucasian European bison Bison bonasus caucasicus (B) (source: Flerov 1932). A: Biaÿowieÿa European bison – the largest living representative of the genus Bison; height at the withers of an adult bull about 1.85 m, larger than the Caucasian. Feet elongated, almost straight hair all over the body, relatively long front coat, coloration lighter than Caucasian, greyish-brown with ocher-brown tint. The tail is covered with long hair.
B: Caucasian bison – height at the withers about 1.6 m, smaller than the Biaÿowieÿa bison. Hooves short, high and rounded. The coat is curly all over the body, the front coat is much shorter than that of the Biaÿowieÿa coat, the color is darker, brownish-brown with a chocolate tint. Tail covered with short hair with a distinct bunch at the end Fig. 2. Differences in the structure of heads and hooves of the Biaÿowieÿa ( lowland ) bison.
A: Biaÿowieÿa bison – the largest living representative of the genus Bison, average withers height of a bull c. 1.85 m, higher than in the Caucasus bison. Hooves elongated, almost straight hair all over the body, relaÿvely long hair on the front of the body, colouraÿon brighter than in the Caucasian bison, grey-brown with a hint of ochre-brown. Tail covered with long hair.
B: Caucasus bison – height at withers about 1.6 m, smaller than the Biaÿowieÿa bison. Hooves short, high and rounded. Frizzy hair over the whole body, the front of the body covered with much shorter hair compared to Biaÿowieÿa bison,
colouraÿon darker, brown-grey with a touch of chocolate color. Tail covered with short hair, a tuÿ of hair at the end


Can you have a bison as a pet?  

Well, that’s a deep subject. The definition of the word ‘pet’ means:
a tame animal kept as a companion rather than for work”
Very few bison would fall into this category, that would be happy. They are a “herd” animal. They are much more content, relaxed, and happy with their own kind. A slim few are born just flat being easy-going and happy. It is rare to have one that is content being your pet and not a productive bison. 

We have our herds that are referred to as pets. This is because they know us and we know them. They are not spoiled, they don’t come in the house, etc.. Usually smaller herds, that learn the routine and what the tractor means, what a whistle means, or a feed truck horn. They know when you shake that bucket it means feed cubes.

Then you have those that want to “train” them to lead or ride…etc… I’m not a fan of this because I know some of the methods being used to accomplish this. There are very few who use humane handling. I would also add those same are not bison producers. Bison producers have a deep passion and respect for the animal.


Bison Biology- Facts About Bison My 2¢- Bison Behavior
Bison show what they are thinking through body language just like your dog or horse. When they get alarmed or concerned, that tail goes up. If the situation worsens, the head lowers, if that threatening presence continues, the bison will show aggressiveness by pawing, walking towards the threat with the head low, or shaking. I saw one bull actually act like he wasn’t paying attention and the whole time he was getting closer to being within reach.  How’s that for smart. A place like Yellowstone can be very different behavior. You’ve seen pictures or videos of people walking right up to them. They then think they are pets, “look he’s not moving!” The reason he is not moving is confidence, he knows he can take you out any second. He does not currently see you as a threat.  He has an escape plan, he can see wide open in front of him.  That thought can change in a blink of an eye. He may be able to walk or run from you, but he may not want to and tells you as much. Then there is “Rut” or mating season, you want to keep a great distance or a safe distance. Many producers/ bison ranchers, ‘have to be around them during this time. They take all the necessary precautions and still, some lose their life or get a helicopter ride and months of therapy. The cow or bull you thought was pretty safe, can surprise you in the worst way. No matter where the bison lives, he is not domesticated. You can treat them like pets, but that doesn’t mean they are a fluffy baby, they are still bison! They still have those wild instincts and they need to be respected. I would bet most if not all bison in North America are desensitized by people. Just some more than others. What that means is, that they know exactly what you are and are not. Remember in history, hunters went to great lengths to stay downwind, hide in wallows, behind trees, in ravens or boulders. So the herd didn’t see or smell them and scatter before they could get a shot off. Not the case today. That fear is gone.  What happens in your presence is what they remember, so it’s up to you as to how they behave. 

Colors: Bull Bourne Bison Ranch_ blk cf

Coat color: Typically American bison (Woods and Plains) are born reddish-orange and change to brown at about 3 months of age, maybe even blackish color. I checked with Alaska as they have different light hours than the lower 48, they said; theirs also change at about 3 months. This calf was born black. (Bull Bourne Bison) some of these calves that are born black will grow up to be the common brown bison while others lean towards blackish.


Bitterroot Bison
Bitterroot Bison – Faith



Horns are black except for albinos. which have white horns, and pick eyes. Faith, who was born last spring (2020) on the Bitterroot Bison ranch in Missoula, fits all the criteria. She has been DNA tested and she is the real deal. Very rare white bison.


Eye color: Faith has pink eyes which is indicative of albinos. She will remain white her whole life.

Normally I would say that all bison have black or dark brown

(looBlondie-amber eyesking black) eyes, (excluding Albinos).   Years ago we bought a load of young bison from a local. In that load was a poor calf which they called Blondie because his hair color was much lighter than what would be ‘normal’ for a bison. The color was odd, but what was even more odd was his eye color. He had amber or yellow eyes. We didn’t think much about it at the time. For all we knew there could be others out there. But here we are decades later and another popped up. A photographer out of Oklahoma published her pictures from Wichita Wildlife Refuge of a bull with amber eyes. Asking if anyone had ever seen this before. Never forgetting about Blondie …I responded. So, I went on the search for more. These images are the work of Susandiann Photography. She was memorized by this bull. When speaking with Daniel McDonald from the refuge, he said the bull was about 16 maybe older, and was born on the refuge. Wichita Mountains Wildlife is basically a closed herd. In 1958 it was reported that four bulls were brought in from Fort Niobrara National Wildlife Refuge in Nebraska. So where did the eye color come from? (Since this post, this bull has passed on Oct 2021 RIP- Old One Horn)

Old One Horn
Old One Horn
Susan Diann Photography









These two images below are ones I found on the internet. The owners were not able to be found, so I will just show them as what they are. (images found on the internet) The Red (first one) is a European bison or  Wisent. The second looks to be a young Plains bull. 

European bison with yellow eyes

Bison with amber eyes


I have reached out to anyone I can think of for help in resolving this mystery. I will keep you all posted with updates as they become available. One thing they all have in common besides being bison is that all are males. Not much to go on, but……maybe a clue?




Bison Wool, 1887-Once a year the great fleece, weighing from 10-14 pounds is shed and its manufacture into thick warm cloth was at one time a regular industry at Winnipeg until it was discontinued by the extirpation of the animals in the adjoining region. 
 1888-Each animal yields from 10 to 12 pounds of this material, and some years ago there was established in Winnipeg a cloth factory for the manufacture of buffalo wool.
Today a couple of sources say 1-3 pounds of down and separated to  8-9 ounces of fine down,  ending up 4-6 after cleaning. 


The Top Notch Hair– The hide hunters as a rule did not remove the skin from the buffalo’s head, which was covered with long coarse hair that never shed; the hair on some of the old Bulls measured from seventeen to twenty-two inches in length.

Bison Biology Hornaday Hair Length


Just a simple example of a few bison. By no means is it a survey of average measures. (1887-Hornaday)




Here’s another rare trait.

"Pink" tongued Bison Cow
                  Pink’s Profile

Bison normally have black tongues. 
Recently I was given permission to share this image. Her name is “Pink” and she belongs to 310 Bison Ranch in Jacksonville, Texas. Owned by Steve Unger.              




310 Bison's Pink
Pinked tongued bison calf
310 Bison Ranch
"Pistol" Black Tongue
“Pistol” Black Tongue










Bulls Mouth


Bison also do not have upper front teeth. They have a dental pad (covered in thick gum) that helps the clamping-down of the lower incisors and thus the tearing action so that the animal can chew and swallow. There are many animals that do not have upper incisors: Domestic cattle, Domesticated sheep, Domesticated goats, Bighorn sheep, Mountain goats, Elk/Wapiti, Moose, Deer (all species and subspecies), Antelope (all species and subspecies), Gnu/Wildebeest, Pronghorns,  Buffalo (both Water and Cape), Giraffes, Caribou, Reindeer, Muskox.




Do bison swim?

Jerlyn Jones Photography
             Jerlyn Jones Photography

“I watched this bison saunter up to the river’s edge…walk into the water and keep walking until the river became so deep it had to swim…before long, all you could see was the bison’s head, shoulders, and tail! It was quite a sight.” Jerlyn Jones Photography





Many thanks to Legacy Valley Bison of Texas for the use of their pictures of some of their great breeding females.
Home of Big Easy their herd sire.

Legacy Female 1Legacy Female 2

This is Lazy G Bison Ranch sharing this handsome fella. They are located in Tennessee

Lazy G Bison TN
2000# Bison Bull


How long is a bisons’ gestation period? Cows give birth usually in the spring after 9 month gestation. Calves will weigh typically anywhere from 30 to 70 lbs. They take no time in getting up, nursing, and ripping around. This cow is 15 years old.

Cow ready to calve

Cow ready to calve
May 3, 12:03 pm
Cow ready to calve
May 5, 11:21 am
Cow getting ready to calve
May 5, 3:34 pm







New calf

New born bison calf
15 hours Old – May 6th 9:30am
New calf with bull
5 days old 10:45am









Everyone always asks about the white powder. It is Diatomaceous Earth, commonly known as D.E.. You can

D.E. bath
May 20th, the calf is now two weeks old.

Read more here: Planet Natural The bison love it! In their eyes, I am giving them a ‘treat’.  I place a bag in their wallow, this is a great place as the bees and other good insects don’t hang out there, but the flies do. 


How fast can bison run?   Adult bison can run 35-40 mph.


What size are bison horns? A bison horn can reach 20 inches long. A bull’s horns are

Development_of_the_Horns_of_the_American_Bison 1889
William T. Hornaday

larger in diameter than a cow’s.

Development of the Horns of the American Bison.
1. The Calf. 2. The Yearling. 3. Spike Bull, 2 years old.
4. Spike Bull, 3 years old. 5. Bull, 4 years old.
6. Bull, 11 years old. 7. Old “stub-horn” Bull, 20 years old.

The buffalo grows to maturity in about three to four years and the age up to six years can generally be told by the horns. A two-year-old bull has horns that turned sharply at the base and stick straight up. Such an animal was called a ‘spike.” At three years the horns are heavier and the tips turn in. At about five years the horns reach their full growth and scene after this they began to splinter off at the point. This continues until some of the older bulls have only short stumps for horns.

The horns of the cows are smaller at the base and they are more curved, also showing rings or wrinkles with age.

A bison has a large, low-hanging head supported by a prominent hump above the shoulder and massive neck muscles used to plow snow away from feeding sites and uses his weight behind it, in combat. Whether it be another bison, gate, or a YNP tourist. 


American bison has 14 pairs or 15 ribs?
1819 Dr. Cuvier of the ménagerie du Jardin des plantes received a young male bison from the United States. The calf was from the Kansas plains and handled by an African American. In 2017 author Charlotte Sleigh wrote in one of her books:

This young specimen was brought to a French menagerie in 1819, accompanied by his African-American keeper. The keeper led the bison by a ring in his nose, and was the only person permitted by the beast – so Saint-Hilaire tells us – to wash, comb and rub him down.

Cuvier claimed that the male bison had 15 pairs of ribs. This has been disputed and repeated several times since even recently I have read on a notable source that the American bison has 14 ribs.

American Bison Male Bison Skeleton
Bison americanus. Male, 10 to 12 years old, from Kansas (M.C.Z. No.91). 

I spent the weekend counting bison ribs on internet skeletons, too embarrassed to admit that this information was confusing to me. I don’t recall any of them showing 15 ribs. Is this bison in France be a fluke? One in a million? Or is the one with 14 ribs a fluke? The book(s) that speaks of the 15 ribbed bison, also says there is a specimen here at Harvard.  So I contacted Harvard and they have the No. 91 mentioned in the book mounted. (above image) it appears to have 14 ribs.  (10-12 yo male from Kansas M.C.Z. No. 91)

I reached out to France as well. But, with the Covid struggles, they are unable to look for it at this time. I asked them to keep it in mind because, Dr, Cuvier, being the man he was, I could not imagine him not keeping the skeleton. After all, it was their first American bison. France did breed him, once to a beef cow and both cow and calf died. Cuvier said, after watching the suffering by the animals, he would never try that again.

ETSU: We have counted 8 specimens and they all have 15 pairs.

American Bison generally has 14 ribs and can have 15 pairs

European Bison Skeleton Drawing
European Bison Skeleton
American Bison Skeleton
       American Bison Skeleton

European bison has 14 ribs and has five vertebrae.

Domestic cattle have 13 ribs. 

Domestic Cow Skeleton
Domestic Cow Skeleton





Bison Hooves:  Bison actually have two hooves on each foot. (cattle do as well)

Bison Hoof Bones


Wichita Mnt. Wildlife Refuge did some measuring before 1960. They show that it didn’t matter how old the bull was compared to the size of his hooves. While the average was 22.5 inches a bull 15.5 years old measured 24.5 inches and a bull that was only 2.5 years old measured 25 inches. Another bull at 12.5 years old measured 26 inches.


What do bison eat? Bison eat a wide array of grasses, weeds, and leafy plants, and tree leaves, typically foraging for nine to eleven hours a day. Once the grasses are gone, they will eat alfalfa and baled grasses to get them through the winters if there is no winter pasture mix. Bison producers can be “Grass-Fed” (meaning grass only) and some feed grains a long with their grasses. I will feed mine whole grains from time to time, as a way to move them where I need them. Bottle calves (orphaned calf) I will introduce a molasses-covered processed grain while they are eating grass and still on the bottle. It’s a soft feed and once they get used to it they like it. I do this to get the nutrition into them, there is nothing better than Mom’s milk, but when that is not an option. There are other health benefits to the calf to introduce them to this choice. (medication if need be- made easier) Orphan Calf
In winter, when the snow covers the ground, the bison can and do use their large heads to move the snow and get to the grasses below. In some cases when the snow has fallen too quickly and too deep, it will trap the bison and they can die. (Prof. Dawson made such a discovery in Montana while he was tracking a herd circa 1875)


Bison digestive system: Bison are ruminants, and have four stomachs (like the beef and milk cows) These chambers allow the bison to break down the feed for better absorption. 
“Bison are also attracted to recently burned areas, therefore, influencing plant diversity. After a disturbance, such as a wildfire, grasses establish before other plant species. Bison prefer these regrowth areas because they have a plethora of grasses available to them without having to graze selectively around woody plant species—woody plants take longer to establish after a disturbance. By grazing in these new grass-dominated sites, bison help increase the local diversity. In other words, a variety of plants have the chance to grow in grazed and burned areas.

Undoubtedly, bison grazing patterns influence the prairie ecosystem. Their foraging is important for plant community structures because woody vegetation can flourish in a grass-dominated landscape. Selective grazing by bison can result in a diverse, heterogeneous landscape of plant species. This preference of grass species can help reduce competition for resources between grasses and woody plant species, certainly increasing species richness and diversity found in the prairie ecosystems.”  (

Microbial community composition along the digestive tract in forage- and grain-fed bison


Bison Bull 1922
On hoof, he weighed more than 1,800 pounds.
Dressed his carcass weighed 800 pounds
Bison hide weight – Hide 150 pounds
Bison liver weight – Liver alone weighed 20 pounds
Bison heart weight – Heart 6 pounds
Bison tongue weight – Tongue 8 pounds

Bison trachea vs Cattle

Bison trachea vs Cattle
Photo courtesy of Ken Klemm of Beaver creek Buffalo in Kansas

These two pipes, bison and beef, are of the same age and size animals.

Bison also have larger hearts and lungs than cattle. They can run what seems to be almost forever compared to cattle.

When summer brings on breeding season, I like to watch the massive bulls fighting for the right to mate. A mature bull can weigh more than a ton, and despite their bulk, bison are amazingly quick and agile. Their small rump allows them to spin quickly on front legs, a great defense to dangerous side attacks from rivals. Thick skulls allow bison to endure the head-to-head collisions that determine who is more fit to pass on their genes. These animals can jump over a 6-foot-high fence, run as fast as a horse and keep going for miles. When bison run, their long tongues roll in and out, forcing great amounts of air through a huge trachea to their lungs. What appears to be a sign of total exhaustion actually provides remarkable endurance. Once bison stop running, their breathing quickly returns to normal, and you realize they were hardly stressed.


By Brian Kenner who works for the National Park Service. He is the Chief of Science and Natural Resources for Badlands National Park. Bison in the Badlands


Biology Bison Trachea 2 Biology Bison Trachea 2



JayBird Rietcheck of Hidden Creek Ranch shared these photos of a bison trachea, the bison bull was two and a half years old and weighing 1300 pounds. The trachea is 4 inches across.






Bison-Infographic Hiram Henriquez
Bison-Infographic by Hiram Henriquez