It has been estimated that up to 100 million bison roamed North America in large herds before settlers began pushing westward. Within 100 years of the Lewis and Clark expedition, bison had almost disappeared.

buffalo in a field near a watering hole

old faithful geyser

(Old Faithful, 1948)

Meet North America's largest mammal

Yellowstone is the only U.S. location where bison have lived continuously since prehistoric times. These genetically-pure descendants of early bison that roamed our nation’s grasslands are very special. In 2015, Yellowstone’s bison population was estimated at 4900, making it the largest population on public lands.

Bison typically forage 9-11 hours a day, eating mostly grasses, weeds, and leafy plants. During winter, their large, protruding shoulder hump makes that possible by allowing them to swing their heads from side to side, clearing snow to create foraging patches.

If you want to try something unique, here's buffalo/cranberry bars made by the Lakota peoples from a traditional recipe. It is a gluten-free beef alternative.

buffalo with snow on its face

Male bison, called bulls, stand approximately six feet tall and weigh as much as 2,000 pounds. At 4-5 feet, females can weigh up to 1,000 pounds, and calves are born weighing 30-70 pounds.

American bison have a huge hump across their shoulders that rises a foot or more above the top of the head. Long shaggy hair covers the hump, and thick body fur allows bison to tolerate temperatures as low as -49°F. In the spring, bison molt their winter coat, losing a large amount of hair. The back half of their coat is short and light-colored. The head is covered with thick black hair ending under the chin like a goatee.

herd of buffalo with calves

Oh give me a home

The terms buffalo and bison are frequently used interchangeably; however, they are two distinctly different animals. True buffalo (Cape buffalo and water buffalo) are native to Africa and Asia. Plains Bison and buffalo both belong to the Bovidae family, but are not closely related.

While the names bison and buffalo are used interchangeably, in North America the scientific name is actually Bison bison bison. Historians think the term buffalo came from the French word boeuf, meaning beef.

old image of a mountain of buffalo skulls

(1892 photo of American bison skulls waiting to be ground for fertilizer or charcoal)

White bison

Bison have always been an integral part of Great Plains tribal cultures, providing food, clothing, shelter, tools, fuel, and spirituality. The Lakota call them tatanka. Chief Sitting Bull was Tatanka Iyotake.

A bison with white fur is spiritually significant to a number of Native American religions and often part of their religious rituals. The coats of buffalo are almost always brown and their skin is dark brown or black. However, white bison do occur. They may be albino with white fur and red eyes or leucistic with white fur and blue eyes. They could have a rare genetic condition that causes them to be born white, then turn brown. Or they are beefalo with white coloration from their cattle ancestors.

White bison are extremely rare. The National Bison Association estimates they occur in approximately one out of every 10 million births.

white buffalo with brown herdmates

Red dogs

A bison and calf nuzzle each other.

Bison calves are usually born in late March through May and are orange-red, earning them the nickname red dogs. After a few months, their fur begins turning dark brown and the characteristic shoulder hump and horns start to develop.

Determining their mood

If you want to judge a bison's mood, don't go by its face. Check the other end. If the tail hangs down and switches naturally, the bison is probably calm. If the tail is standing straight up, it may be ready to charge. Regardless, bison are unpredictable and can attack at any time. Each year, hundreds of injuries are caused by people venturing too close to these massive animals.

Bison are not only big, they’re also quite fast, running up to 35 mph. They’re extremely agile and able to turn very quickly, jump high fences, and are strong swimmers.

buffalo in full run across field

(Jack Charles on Unsplash)

Important eating habits

Like cattle, bison have four stomachs. Rumination, along with a four-chamber stomach, makes it possible for them to absorb plant cellulose that's difficult to digest.

Bison forage a wide array of grasses and sedges commonly found in mixed-grass prairies. Although bison graze heavily on grass species, they occasionally consume woody vegetation. By eating mostly grass and selectively avoiding other plants, bison create a pattern of grazed and ungrazed areas.

These areas resemble a patchwork quilt of various plant species. After a wildfire, grasses establish before other plant species. Bison prefer areas containing abundant grass without having to eat around the woody plants that take longer to establish after a disturbance. Bison increase biodiversity by allowing a variety of plants to grow in burned areas. Higher plant biodiversity increases plant cover, gas exchange, and biomass. Photosynthesis also increases due to the increased light and reduced competition for water and nutrients.

Bison grazing patterns greatly influence the prairie ecosystem. Their selective foraging is important to prevent woody vegetation from flourishing in grassy landscapes. The result is a landscape of diverse plant species in the prairie ecosystem.

someone feeding a buffalo from car window

Brucellosis

Transmitted by aborted fetuses, brucellosis is a highly contagious bacterial disease affecting cattle, bison, elk, and deer. Carried by females, it can cause infertility, abortions, and scarce milk production, making it especially devastating for those whose livelihood depends on livestock.

Although there are no documented cases of brucellosis transmission from bison to cattle, approximately 60% of female Yellowstone bison have tested positive for the disease. However, testing positive doesn't mean an animal can transmit it.

Yellowstone National Park must adhere to state and federal laws designed to keep the bison population in check. In 1995, the state of Montana sued Yellowstone after bison wandered onto private land. This led to the creation of the Interagency Bison Management Plan that set a limit of 3,000 bison in the park. However, bison breed 10 times faster than humans, which causes their numbers to rise as much as 17% annually.

To avoid killing these beautiful beasts, Yellowstone officials tried to find a middle ground by sending them to Fort Peck, home of a Montana quarantine facility and Native American reservation. There the animals could be tested for brucellosis rather than killed. However, that process can take up to a year. Although a vaccine (RB51) was approved for cattle in 1996, it is not yet approved for bison.

The state of Montana rejected the plan. Ranchers believed it was still too risky to transport bison near their cattle unless the animals received a clean bill of health before transport and were released somewhere else.

buffalo near an information sign in Yellowstone

Current numbers

Today, the National Park Service informs tribes about the number of bison available. Tribes contract with cattle haulers to pick them up in Yosemite. The large hides and abundant meat go directly to the Native American tribes that contracted with the haulers.

As of fall 2016, Yellowstone National Park estimates the wild bison population at approximately 5,000. This population is comprised of at least two distinct sub-populations, the northern and central herds. The number is dangerously low when compared to the tens of millions that originally roamed across North America. It is mistakenly argued that 3,000 is too many bison because that number exceeds the ecological carrying capacity of Yellowstone's habitat.

Thus, the ongoing bison slaughter continues. A recent scientific study suggests bison have not reached a theoretical food-limited population of 6,200 in Yellowstone. However, results of an Oregon State University study suggest the increasing numbers are now a barrier to ecosystem recovery in the northern part of the park.

Honor the buffalo with this made in USA buffalo nickel money clip. The nickels are reproduction, however it is a nice addition to your western collection or as a gift for some who loves the west.

close up of buffalo face

When you purchase through links on our site, we may earn commissions at no cost to you.