Bison of the Bighorn Basin Project
Created on July 1, 2021
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Bison of the Bighorn Basin
A project dedicated to learning more about bison morphology, or shape, and ecology within the geographic Bighorn Basin. Join us in exploring the story of the bison.
Thank you to our sponsors, advisors, funding sources, and the Bighorn Basin Community for their participation and support of this project.
Sam May, Antlers Ranch
Dr. Kenneth Cannon, Cannon Heritage Consultants, Inc.
Dr. Lawrence Todd, GRSLE Archeaology
Dr. Chris Widga, Head Curator of the Gray Fossil Site
Jason Baldes, Executive Director, Wind River Native Advocacy Center
Dr. Jeff Martin, Director of Research for the Center of Excellence for Bison Studies
Think About It!
Bison or Buffalo?
"American Bison" courtesy of USFWS Mountain Prairie.
The scientific community refers to the American bison using its scientific name, Bison bison bison. Bison are from the family Bovidae, the same genetic family as cattle.
When Europeans first encountered bison, they called them “buffalo” perhaps because of their resemblance to the African buffalo. The name stuck and today many refer to the bison as “buffalo”. Bison and buffalo are not the only names for bison. The numerous Native American tribes of North America co-existed with bison for over 14,000 years and called the bison names including: Iinni, Tatanga, Tatanka, Paskwâwimostos, Xaniti, Qwisp, Kamquq̓ukuǂ ʔiyamu, Iyanee, and more.
What do you want to learn about?
North American conservation was just beginning as bison populations plumeted. Learn more about saving this icon of the Great Plains.
As of 2016, the bison became the national mammal of the United States. At the same time, bison are being returned to the landscape.
What the measurements of 106 bison crania in the geographic Bighorn Basin tell us about bison.
The Bison Project
Bison have a long history in North America, learn more about their relationships to the environment, people, and more through time!
Story of the Bison
200,000 years ago
14,000 years ago
10,000 years ago
3,000 years ago
Imagine being transported back through time. Civilizations rise and fall until there are no permanent settlements. You stand in a very different landscape from today but there is a familiar animal in front of you- the bison.
History of Bison in North America
Close to 200,000 years ago bison first entered North America by way of the Bering Land Bridge. This was a time known as the Pleistocene and glaciers, huge sheets of ice, covered much of North America. As the glaciers receded, they created corridors through which the bison could disperse across the continent.
Humans arrive in North America roughly 14,000 years ago. Because bison exist in both Asia and North America, the first humans in North America were likely already familiar with bison as a prey species. North American bison, however, were suddenly sharing the landscape with a new predator, one that could rapidly change its behavior and hunting techniques.
The Horner Site outside of Cody, Wyoming sits on a flat terrace above the Shoshone River. The site is a mass kill site which dates between about 10,500 and 11,500 years old (calibrated Frison dates Table 4.1). The lack of natural features or drive lines separates the Horner Site from many other kill sites. The bison at the Horner Site appear to be lying where they were killed, on the open terrace.
Modern bison morphology (shape) emerges on the landscape. All the bison measured during the Bison of the Bighorn Basin Project are morphologically modern, meaning they date from within the last 3,000 years.
Christopher Columbus “discovers” North America. Columbus, not realizing his error in navigation, initially believes he is in India and calls the Indigenous Peoples “Indians.” The term would stick around, being used by Europeans and their future descendants to address all North America’s Indigenous Peoples, regardless of tribal affiliation or identifiers. His accidental “discovery” set into motion a series of events that would impact all American residents, including the bison. Europeans brought with them new diseases including brucellosis and a demand for the warm furs from the “New World” including bison hides. This would reach a peak in the late 1800s.
Idaho Territory passes a mandate stating that bison should not be hunted at all. At the time the mandate was passed, there were no bison remaining in the state outside of what is today Yellowstone National Park.
Two years after the end of the Civil War, a member of the U.S. Army reportedly ordered his troops to “kill every buffalo you can. Every dead buffalo is an Indian gone.” The following year, General Sherman wrote to General Sheridan stating, “I think it would be wise to invite all the sportsmen of England and America…this fall for a Grand Buffalo hunt … and make one grand sweep of them all.” On 26 June 1869, the prestigious Army Navy Journal reported that “General Sherman remarked, in conversation the other day, that the quickest way to compel the Indians to settle down to civilized life was to send ten regiments of soldiers to the plains, with orders to shoot buffaloes until they became too scarce to support the redskins.” Removal of bison from the landscape directly impacted the ability of Native American groups to wage war against the United States for their traditional lands.
From April - November of 1868 the Treaty of Fort Laramie was negotiated and signed. The treaty was the newest in a series of failed attempts to negotiate peace between the Sioux, Arapaho, Cheyenne, Crow, Assiniboine, Arikara, Hidatsa, and Mandan tribes and the United States government. Among the other things, the treaty established the tribes' rights to hunt bison "so long as the buffalo may range thereon in such numbers as to justify the chase."
Wyoming Territory prohibits the waste of bison meat. Though timely, unfortunately, the law was not enforced.
“The Shoshoni were allowed to make a seasonal bison hunt after settling on the Wind River Reservation in 1868. As late as 1874, and possibly for a few more years, the Shoshoni travelled to the Bighorn Basin to hunt. James Patten, government teacher on the reservation, accompanied Chief Washakie and the Shoshoni in October 1874. From Wind River they crossed over the Owl Creek Mountains into the southwestern portion of the basin and found bison ‘herds on the Gooseberry about forty miles from its mouth,’ or west of the Bighorn River, where they killed ‘one hundred and twenty-five buffalo.” – Blazing the Bridger Trail Route, pg. 59
Otto Franc visits the Bighorn Basin during a hunting trip from 1878 and picks out the location of the Pitchfork Ranch on his journey. During their trip, Franc and his party hunting bison regularly. On September 7, 1878, Franc writes,
... not wishing to waste powder at such miserable game I return to our party & the buffalo go off at a slow trot, all my illusions about buffalo hunting formed from books of western adventure are dispelled & I look upon [it] as the worst kind of sport hunting in which no true sportsman will indulge; I am speaking here only of hunting the Bulls, we have seen no cows or calves yet but we hear they are much more wary and wild.
He goes on to write that having tasted bison meat he found it, “in all cases almost entirely unfit for food being tough & stringy.” He relates that for the most part, his company would just remove the tongues of bison, despite the meat wastage being illegal in Wyoming Territory at the time.
Only an estimated 325 wild bison remain in the United States, 25 of which were located in Yellowstone National Park.
Meeteetse is established as a town. The same year, the United States Army takes up residence in Yellowstone National Park on August 20, 1886. Their presence in the park helps bison populations which increase from the 25 of 1884 to roughly 200.
Tom Osborne, foreman of the Pitchfork Ranch from 1884 to 1894, reported, “The last wild buffalo was on Meeteetse Rim at the head of Horse Creek in 1892. About seven cowboys with six-shooters kept up with the animal and peppered him until he dropped” (Meeteetse Museums Archives).
Ed Howell is arrested for slaughtering bison in Pelican Valley of what is today Yellowstone National Park.
The first law to protect bison and other wildlife species within the boundaries of Yellowstone National Park is passed.
The United States Army turns their National Park duties over to Park Rangers.
The Buffalo Treaty is first signed on September 24, 2014, at the Blackfeet Reservation in Montana by the following nations: Blackfeet Nation, Kainai/Blood Tribe, Siksika Nation, Piikani Nation, the Assiniboine and Gros Ventre Tribes of Fort Belknap Indian Reservation, the Assiniboine and Sioux Tribes of Fort Peck Indian Reservation, the Salish and Kootenai Tribes of the Confederated Salish and Kootenai Indian Reservation, and Tsuut’ina Nation. Today, the Treaty has 31 signatories who meet annually to celebrate the work they've completed in the past year and plan for the future.
In October of 2019, the Eastern Shoshone signed the Buffalo Treaty in Chico Hot Springs, Montana. That same month the InterTribal Buffalo Council signed the Treaty as well.
In 2016, the bison was declared the United States' national mammal.
This photograph, courtesy of Dr. Lawrence Loendorf, shows a bison petroglyph at Legend Rock. Petroglyphs are created by pecking the stone. Many petroglyph (pecked) and pictograph (painted or drawn) image sites like Legend Rock are sacred.
Bison as Kin
For over 14,000 years in North America, bison co-existed with humans. Today we know those people collectively as Native Americans. For many Native Americans dwelling on the Great Plains, known as the Plains Tribes, the bison were a main food source. But bison were more than just a meal — they were and are viewed as kin or family. This relationship was exploited by Euro-Americans in the mid-1800s through the deliberate slaughter of bison by the hundreds of thousands.
"American Bison" courtesy of U.S. Fish and Wildlife Service - Midwest Region.
“The buffalo to the Shoshone People were very important like many other Native American tribes. The buffalo was life’s commissary, so everything that we needed came from that animal and our people thrived on the wildlife economy, the buffalo economy, the wildlife … biodiversity of plants and animals is what allowed our people to thrive and flourish. And so, the name for ourselves, we’re the Eastern Band of the Shoshone, but the name for ourselves is the Gweechoon Deka, the Buffalo Eaters. Because we distinguished ourselves by the foods we ate. And so, there’s the Sheep Eaters, the Salmon Eaters, the Rabbit Eaters, we’re the Buffalo Eaters. And so, the buffalo was not only life’s commissary, but it was also central to our spirituality and belief systems. Our relationality to the planet, to the earth, to the inhabitants and so the buffalo was a central part of that medicine wheel philosophy. And so, they’re a very important animal not only to Shoshone People but to many other tribes.” - Jason Baldes, "Meeteetse Stories" Podcast Season 2 Episode 4
Bison were important for their meat, but the relationship between bison and many Native American tribes goes much deeper.
Photograph of Sioux people drying meat on racks, courtesy of the McCracken Research Library P.35.174.
Spiritual/Celebratory Role of the Bison
The bison gave Native American tribes food, shelter, and clothing and in return, the tribes honored the bison through ceremonies and spiritual practices. Today, though many Plains Tribes have not had access to the bison for many years, bison are being returned through reintroduction efforts. The physical return of bison brings with it healing for both the buffalo and the tribes. For some, the bison is a living symbol of tribal resilience and survival.
This ceremonial mask was used in a Mandan Okipa ceremony which dramatizes the tribe's origins and creation of earth. The ceremony took place before the buffalo hunt, bringing the herds closer to the village. NA.203.359. Plains Indian Museum. Buffalo Bill Center of the West.
An understanding of animal behavior allowed North America’s first humans, commonly referred to as “Paleoindians,” to exploit the natural instincts of animals. This knowledge combined with an intimate, cultural knowledge of the landscape made Paleoindians effective hunters. For over 14,000 years, bison were hunted individually in encounter hunts, in large groups, driven over cliffs, run into arroyos, trapped in sand dunes, and killed in places with no natural containment.
Photograph of Sioux people drying meat on racks. Notice the internal organs at the far left of the photograph. PA.35.174 courtesy of the McCracken Research Library, Buffalo Bill Center of the West.
Paleoindians would sometimes move their people to the location of the kill. There, they would butcher the bison and camp at the site until they were forced to move on looking for more food.
Photograph of stone tool cut marks on a bison radius courtesy of Dr. Lawrence Todd, GRSLE Archaeology.
Butchering with stone tools
Domesticated dogs made it easier to transport meat. It was now possible to butcher multiple bison and then transport the meat to more desirable camps on a travois tethered to the dogs.
Native American woman holding staff with dog pulling travois. P.35.191. MS 35 North American Indian Photograph Collection. Courtesy of the McCracken Research Library, Buffalo Bill Center of the West.
After 1519, the reintroduction of horses to North America by the Spanish made it possible to transport even larger quantities of meat. The Vore Buffalo Jump is an example of a site that illustrates how this transition from using dogs for transportation to horses was reflected in butchery practice.
This photograph shows Crow people breaking camp and using travois pulled by horses to haul their possessions. This same method made it possible to move people and meat to and from butchery sites with ease. Photograph courtesy of the McCracken Research Library, P.35.215.
In addition to playing a spiritual role for tribes, bison featured prominently in material possessions.
Toys for the young served many purposes for Native Americans. While a source of entertainment, toys could teach skills that would be important as an adult, teach cultural values, and more. Materials from the bison were used in many toys. Bison horns were used by the Apsáalooke (Crow) as spinning tops. The hide and sinew from the bison were used to make dolls which could instruct children about cultural values, societal roles, and decision making. Sinew and hide toys could also be used to teach hand-eye coordination.
Learn More about Buffalo Robes:
Nebraska's Metropolitan Community College Buffalo Robe Project, 2013
The Museum Journal by the Penn Museum, "A Buffalo Robe Biography" by Henry Usher Hall
Bison are large animals, and every piece could be used. Their bones could be made into tools to make foraging easier (shovels, awls, digging sticks) or to help them when they were processing future kills through fleshing tools and scrapers. The horns could be used for utensils, cups, and to transport fire. Tendons were made into strings for bows and sinew. Hooves made rattles, spoons, and glue. The bladder made containers to transport food, water, and medicine. Teeth, hair, and the beard could be used for ornamental purposes. Fat could be made into tallow, soap, hair grease, or used to tan the hide. Even the gall bladder was used for its yellow pigment.
Altogether Plains Indians had over 150 uses for various components of the bison, but this did not mean that every bison was used in its entirety. Leaving some parts behind provided for other inhabitants of the ecosystem.
Bison and Conservation
Brink of Extinction
When Europeans first came to North America, an estimated 30 to 60 million bison roamed the Great Plains.
William Jacob Hays, Sr. (1830-1875). A Herd of Bison Crossing the Missouri River, The Herd on the Move, 1863. Oil on canvas, 36.125 x 72 inches. Buffalo Bill Center of the West, Cody, Wyoming. Gertrude Vanderbilt Whitney Trust Fund Purchase. 3.60
When Euro-Americans reached the Great Plains, they began to trade with many Plains Tribes for valuable bison hides. The hide market was first dominated by Plains Tribes who would trade the hides for various goods.
George Catlin, an artist who also portrayed scenes of the West in his work, wrote in a May 1832 report that he had learned that hundred of the men from the tribe had gone hunting for bison despite having “full larders” so they could obtain tongues for the American Fur Company in exchange for gallons of whiskey. Early in the trade of bison hides, Native Americans were the primary hunters. Though while they were in control of the market (by being the distributors), the trades were oftentimes unfair, favoring the American Fur Company rather than being equal.
After the Civil War the market shifted and Euro-American men became the primary "hide hunters." The demand for hides was insatiable as both the American and European market called for more.
The lucrative market soon attracted European-descendant hunters who would kill as many bison as they could to strip them of their hides, leaving the bodies to rot.
On the Brink of Extinction
Photograph of Rath & Wright's buffalo hide yard located in Dodge City, Kansas in 1878. There are 40,000 buffalo hides in this photograph. That is more hides than the population of Laramie, Wyoming. Courtesy National Archives, photo no. 26-G-3422.
William F. “Buffalo Bill” Cody’s Reflection on the hide market:
“I had a force of men with me to skin and cut up the animals I shot, and after the railroad builders were supplied I was the first man to ship buffalo meat to Europe. I sent it by express, shipping only hindquarters and tenderloins, with the hide left on to prove that it was clear, sure enough buffalo meat. The number of animals killed by me and by other white men and all the tribes of Indians, for food, would seem enormous if it could be correctly written down, yet all that killing, so long as it was confined to such legitimate supply, did not seriously diminish the herds. The Indians did not kill so many buffaloes as the white men, because they never killed wantonly. They only slaughtered what they needed for the flesh to eat, or for the hides to make lodges or robes.
But the death knell of the buffaloes sounded when white men got to killing them for their hides, simply to make leather. For that use they could kill at any season of the year, and they did, cruelly, recklessly—exterminating them for the sake of the two or four dollars each they got for the hides, and leaving the carcasses by hundreds of thousands to rot on the plains. There was no refuge or relief for the buffaloes anywhere. The hide-hunters followed them, in hundreds, from Texas clear up to the British possessions, slaughtering and skinning, until they finally wiped them out.” Source: https://codyarchive.org/texts/wfc.nsp09021.html
Removal of bison impacted the ability of Native American groups to survive or defend their traditional lands against the United States. The slaughter reached its peak in the 1870s and 1880s, and bison numbers fell to their lowest point, roughly 1,000 in North America. Only approximately 300 of those were Bison bison bison while the other 700 were Bison bison athabascae, or wood bison.
L.A. Huffman photographed a changing frontier in the late 1800s and early 1900s. From 1880 until 1883, Huffman photographed the prairie surrounding Miles City, Montana. The result was some of the last photographs of wild bison on the Great Plains.
Bison hunting was hailed as an "American sport" that could be won by whoever killed the most bison. The Army relied on this sport to keep idle troops entertained on the frontier.
Despite playing a hand in their extermination, the US Army would soon be tasked with protecting one of the remaining wild bison herds in Yellowstone National Park.
Nick Eggenhofer (1897-1985). Col. Cody Hunting Buffalo, ca. 1952. Gouache on board, 15.5 x 13 inches. Buffalo Bill Center of the West, Cody, Wyoming. Gift of the artist. 39.73
The Buffalo-Hunt, Camp Seventh United States Cavalry, Near Fort Hays, May 28, 1867. Harpers Weekly, July 6, 1867, page 426. MS51.337-Pg426. McCracken Research Library, Buffalo Bill Center of the West.
Bison were saved from extinction in large part due to the North American Model. The model originated during the late 19th century in large part thanks to Theodore “Teddy” Roosevelt. During Roosevelt’s presidency, the National Parks were designated as areas of preservation meaning their resources could not be used while the subsequently formed National Forests were conservation areas for wise-use.
The North American Model is an approach used by agencies today for the use of natural resources. It is because of the North American model that the number of hunting tags vary from year to year as wildlife biologists try to manage wildlife populations.
The North American Model
In 1886, William Temple Hornaday, the Smithsonian's United States National Museum's chief taxidermist, was sent to Montana to collect bison specimens for display. Hornaday had been a big game hunter before his position at the National Museum. Like many early conservationists, Hornaday's background in hunting was a major factor in his interest in wildlife populations. Hornaday had seen the large herds of bison before his 1886 trip and was shocked to see them diminished.
During his trip to Montana, Hornaday collected the bison seen in this exhibit and subsequently dedicated his life to preserving the species. He acquired two live bison to be displayed for the public at the Smithsonian, they were the start of the Smithsonian's National Zoo which was founded in 1888. The following year, Hornaday published "Extermination of the American Bison with a Sketch of Its Discovery and Life History" which popularized the effort to save bison from extinction. In 1905, Hornaday organized the American Bison Society which helped to put bison from zoos back into conservation herds, the first of which occurred in 1907 as fifteen bison were donated to the Wichita National Forest and Game Preserve in Oklahoma.
For more information:
Smithsonian Museum virtual exhibit "William Temple Hornaday- Father of the American Conservation Movement."
Private conservation of bison is the main reason we can view bison today in places like Yellowstone National Park. When the bison population numbered only 1,000 individuals, many of them were part of private herds and necessary for the revitalization of the species. The Bighorn Basin’s most famous resident and Cody, Wyoming’s namesake, Buffalo Bill, was the owner of one such herd.
Buffalo Bill stands on the front porch of the lodge at Pahaska Tepee in 1903. Photo courtesy of Park County Archives.
William F. “Buffalo Bill” Cody killed 4,282 bison in an eighteen-month period in 1868 for the Union Pacific Railroad.
After establishing a hunting lodge outside of Cody, Buffalo Bill began noticing a decline in large game species and soon became an advocate for conservation and limits on hunting.
In a direct reversal of his actions and ideas in 1883, Cody publicly wrote the New York Sun in support of U.S. Senator George Graham Vest’s bill to increase protections in Yellowstone National Park. Cody never joined any conservation organizations and was well known as a bison hunter. However, in 1902 Cody did lend twelve of the bison from his private herd (used to supply his famous Wild West show) to the Zoological Park in Washington, D.C. Those bison were part of a conservation effort to reintroduce bison across the country. From that herd, bison were sent to the Wichita National Forest and Game Preserve in Oklahoma.
At the end of the 19th century bison were interbred with cattle. The interbreeding was an effort to make cattle better able to deal with the cold winters of the West. Interbreeding resulted in the presence of cattle genetics in many herds. Genetically-pure bison, like those at Yellowstone National Park, do not have the introgression of cattle genes. Because of the near-extinction of bison, genetically-pure bison are important for maintaining genetic diversity in herds across North America.
Buffalo Bill's hunting party in front of the lodge at Pahaska Tepee. Photo courtesy of the Park County Archives.
William F. "Buffalo Bill" Cody, photograph courtesy of the Park County Archives.
One of Buffalo Bill's bison at Cody, Wyoming. Courtesy of Park County Archives.
Almost twenty years after Buffalo Bill renounced his actions, the Army was tasked with protecting the bison in Yellowstone National Park- one of the remaining wild herds. Within just a few years, the bison population increased, but bison would not freely roam the Great Plains again. Today there are an estimated 362,406 bison in North America. One hundred eighty-three thousand seven hundred and eighty of those bison are in private herds. Bison are the only mammal native to North America that can be farmed without a permit
When the Land Belonged to God Charles M. Russell Oil on canvas, 1914 Montana Historical Society Collection, X1977.01.01
Archaeology vs. Paleontology
In the United States, there are laws governing the collection of non-renewable resources. These resources cannot be replaced which means both archaeological and paleontological remains are subject to this legislation.
Archaeology is the study of human history through excavation of materials left behind.
Paleontology is the study of fossils including dinosaurs, plants, and animals.
Photograph courtesy of Larry Todd depicts an archaeologist excavating site 48PA563 in August of 1984.
Excavation courtesy of the Wyoming Dinosaur Center, Thermopolis, Wyoming
Archaeology vs. paleontology
Wild bison have been absent from the Bighorn Basin since the late 1890s. This means, any bison remains found in the area are either archaeological or paleontological finds.
A pile of bison skulls and elk antlers at the TE Ranch. P.6.1618, McCracken Research Library, Buffalo Bill Center of the West.
Humans have made their home in Wyoming for more than 13,000 years. Reminders of this long history are scattered across the landscape in the form of the archaeological record.
The disturbance or removal of archaeological resources on Federal lands (for example, Forest Service, BLM, National Parks) is illegal under the Archaeological Resources Protection Act (ARPA) of 1979.
The official purpose of ARPA reads:
“The purpose of this chapter is to secure, for the present and future benefit of the American people, the protection of archaeological resources and sites which are on public lands and Indian lands, and to foster increased cooperation and exchange of information between governmental authorities, the professional archaeological community, and private individuals having collections of archaeological resources and data which were obtained before October 31, 1979.”
Read the act in its entirety here.
ARPA applies to both surface and sub-surface resources found on federal public lands that were collected after October 31, 1979.
There's more than meets the eye when it comes to archaeological resources. Archaeologists use a variety of different approaches to make inferences about the past. Explore a site to learn more!
Excavation at the Bugas-Holding Site in 1984 of the occupation surface, photograph courtesy of Dr. Lawrence Todd.
Photo courtesy of the Wyoming Dinosaur Center, Thermopolis, Wyoming.
Explore a Site
What can we learn from an archaeological site? Pick one to find out!
The Horner Site consists of Horner I and Horner II and is located outside of Cody, Wyoming. The site dates between about 10,500 and 11,500 years old (calibrated Frison dates Table 4.1).
Photograph of the Horner Site excavations by University of Wyoming courtesy of Dr. Lawrence Todd.
48PA201 is a rockshelter on the banks of the North Fork of the Shoshone River that was occupied from approximately 7280 B.C. to 1580 A.D.
Photograph of the Mummy Cave, courtesy of McCracken Research Library
48PA563 is a Shoshonean winter camp located in Sunlight Basin occupied during the Late Prehistoric Period (after 1300 A.D.).
Photograph of 48PA563 during excavation courtesy of Dr. Lawrence Todd.
What is a Site? A "site" refers to a group of artifacts. According to the Wyoming State Historic Preservation Office, a site is either 15 prehistoric artifacts within a 30 meter area or one feature. Anything under this threshold is labeled as an isolate. For sites consisting of historic artifacts, there must be 50 or more within a 30 meter area. The sites can be much larger than the 30 meters, but this provides guidelines for survey crews to determine what they do and do not report. Some of these sites will then get excavated to learn more.
The Horner Site
A feature is a non-moveable element of an archaeological site. While artifacts, like stone tools, can be moved from the site, a feature remains in place. Examples include trash pits, hearths, walls, and more! Because they cannot be created by natural processes, features indicate human presence at a site.
Horner I, shown here, represents a wide range of activities including hide processing. This could mean it was a short-term occupation site, likely used during the late fall or early winter. The area contains well over 100 bison.
Map of the Princeton-Smithsonian excavations of 1949-1952 from "The Horner Site: The Type Site of the Cody Cultural Complex" edited by George C. Frison and Lawrence C. Todd.
Analysis of sites depend on the artifacts or objects being found in situ. In situ means the objects are found where they were left originally. This is important because of the surrounding context. A projectile point embedded in a rib bone beside a hearth tells a much different story than a lone projectile point or rib bone.
The remains of bison found at the Horner Site are full of information. From analyzing bones, archaeologists can learn approximately how many animals were killed during the event (known as the MNI or minimum number of individuals), how the bison were butchered, if they were gnawed on by carnivores, and even seasonality of death. At Horner Site 1, examination of dental eruption (when teeth emerge) indicated the animals were all killed in late fall or early winter. The bison may represent a single event or repeat kill events all taking place in the same location in the same season.
Feature 13, viewed here, may have been a storage pit, post-hole for a structure or drying rack, cooking pit, related to the location of the kill, or some other as yet undetermined use.
Feature 25 is a charcoal scatter interpreted to be a hearth or fire. Fires during butchering could be useful in a variety of ways including cooking, processing of fats, providing light to work by, or protection from predators.
Stone tools, also known as lithics, give insight into the activities being performed at the site. Different tools were used for cutting, scraping hides, killing the animal, and more. At the Horner 1 site depicted here, analysis of the stone tools led to the conclusion that the site shown here was used for cutting and skinning of the hides and hide working. One of the researchers E.N. Wilmsen suggested, "it is likely that Horner represents an annual harvest of fresh pelts for conversion into warm winter robes.”
The Horner Site was discovered by James M. Allen on July 2, 1939. After finding the site, Allen developed an interest in seeing the site investigated further and showed the site to Dr. Glenn Jepsen of Princeton University. Jepsen began excavating the site in 1949 and in 1951, turned to the Smithsonian Institution for assistance in excavating the site. Princeton and the Smithsonian would excavate the site 23 years before the University of Wyoming conducted two field seasons at the site in 1977 and 1978.
Leaving portions of archaeological sites is common practice as it allows future archaeologists to come back with more advanced technology and learn even more! At the Horner Site, this happened two times after the first 1949 excavation.
Archaeological sites are divided into excavation blocks. Today, excavation unit typically measures 1 meter x 1 meter. Each archaeologist is assigned to excavation unit. They are tasked with mapping items withing that area as they excavate, making it possible for maps like this one. Each block as a name designated by a letter and number as well as a metric locational designation.
Sometimes referred to as "Mummy Cave" because of the ancestor's remains found in the cave, site 48PA201 represents almost 9,000 years of continuous occupation. The rockshelter's dry conditions resulted in the preservation of perishable objects such as baskets, wood, hide, and feathers alongside the more frequently seen projectile points, chipped stone knives and scrapers, faunal remains and tubular bone pipes. As each layer was radiocarbon dated, archaeologists were able to establish a timeline for changes in the shape of projectile points. This timeline can be used to estimate the age of an undated site.
48PA201 consists of 38 unique stratigraphic layers. This level of preservation is unique for a site, especially in Wyoming. Archaeological sites usually deal with things like burrowing rodents which disturb the layers. Additionally, windy Wyoming tends to be an environment of erosion rather than deposition.
These two images show rodent burrows on the surface (left) and underground (right). Known as krotovina these burrows can cause a mixing of layers. Site 48PA201 does not have any krotovina. Photographs courtesy of Dr. Lawrence Todd.
Projectile points, or arrowheads and dart points, are diagnostic artifacts. This means their shape changes regularly through time. Projectile points can be used to relatively date layers in excavated sites or when found on the ground surface.
Here in the West, many collect projectile points because of their beauty. When they remove projectile points from the landscape, they also remove the quickest way archaeologists can tell time. Some sites studied now are void of these diagnostic artifacts, sometimes requiring advanced analysis like radiocarbon dating to get a date of occupation and sometimes no longer datable at all.
The stratigraphic layers in 48PA201 are numbered 1 (the oldest layer) to 38 (the youngest layer). The numbering system allows for each layer to be interpreted which contributes to our understanding of the site as a whole.
Layers 19-23 date from 6,900 to 6,000 years ago. According to the site report by William Husted and Bob Edgar, the thinness of these layers suggests sparse population in Wyoming and at the site at that time.
Stratigraphy refers to the layers of sediment that build up over time. The youngest layer will be on top while each layer under that will be older. Archaeologists excavate these layers to learn more about people through time.
In radiocarbon dating, the decay of carbon-14 is measured. Carbon-14 is incorporated into living organisms through plants consumed during its lifetime. During an organism’s lifetime, levels of carbon-14 in the body remain relatively constant. When an organism dies, the carbon-14 begins to decay at a predictable rate allowing us to estimate when that organism died. This date is presented as Radiocarbon Years Before Present but can be calibrated to years before present or as calendar years (AD or BC). The half-life of carbon-14 is 5,730 years and radiocarbon dating can be used to date organic remains to roughly 50,000 years.
Cross-dating uses material culture that changes in a predictable way through time, such as projectile points or pottery, to estimate the age of an undated site.
48PA563: Bugas-Holding Site
48PA563 was discovered during a gas line trench excavation. The site was first tested in August 1983. The site was occupied from November until early spring (March/April) about 1300 A.D. After the site was abandoned, it was quickly covered with sediment from alluvial flows.
Every archaeological site has a datum. The datum sets up the grid system used to keep track of everything that comes out of the site. You can see the grid on the site map, but it's not just a conceptual grid drawn on after the excavation. The grid guides the excavation.
Each grid unit, usually 1 meter by 1 meter, is given a name. The larger block is then divided into four quadrants. When an object comes out of the excavation block, its location is recorded. That location includes the block name, quadrant within the block, relation to the datum (i.e. its location north and east within the site), depth, and orientation (for example, which way the object's long axis is facing).
Tools at Bugas-Holding were repurposed from existing tools, but not likely created from freshly collected material. On stone tools you can tell how close a piece was to its raw material source (for example, a unaltered cobble of chert) based on something called cortex. Cortex is the outer shell of the rock. The closer flakes were to the outside of the rock, the more cortex they have on them. Additionally, flakes that are used to make stone tools are taken off cores. A core is a large block of raw material that is used to get smaller bits off.
Excavations at 48PA563 found that the lithic debitage, flakes from making and resharpening stone tools, were concentrated around the up-wind sides of the 8 hearths that make up the site. The absence of cores, large pieces of raw lithic material, suggests the inhabitants of this site were primarily re-using tools brought there at the beginning of occupation.
Eight hearths are scattered throughout 48PA563. The hearths are filled with wood ash, charcoal, and fragments of burnt bone and stone tool resharpening flakes. Additionally, the destruction of articular ends of bones (where you would find a joint) suggests processing the bones for grease was found across the site. Marrow is rich in nutrients, needed during the long winter months when higher-fat food is rare.
One of the ways archaeologists can learn more about sites like this one is through a process known as refitting. Age, sex, and species are used to determine which bones are likely to have come from one individual animal. From this information, it is possible to see relationships throughout the site as bones from a single individual are found throughout.
At Bugas-Holding, refitting indicates the bones received initial processing at Hearth 2 and 5 in the center of the site. Subsequently, parts of the different bones were moved to other locations in the site. For example, the distal ends of bones which are marrow rich were moved to Hearths 6 and 7 where they were likely processed further. Bulky bison crania were broken open at Hearth 2 before being moved to Feature 9, a probable dump.
Seasonality refers to what season a site was occupied. Animal bones help archaeologists learn what season a site was occupied. At this site, there were seven fetal bison. Since bison give birth to their young in the spring, archaeologists can estimate what months the site was occupied based on fetal development. Like humans, bison develop their skeleton in predictable stages. For example, in humans the cartilage growth plate known as the anterior fontanelle in our heads fuse between 9 and 18 months. Two of the infant bison were estimated to be 7 months old, putting occupation of the site in December.
During excavation, the provenience of each object is recorded. Provenience is essentially an object's origin. This origin can be general (this object came from 48PA563) or very specific (this object came from site 48PA563, Level 3, Block B). In an archaeological dig, provenience is marked as precisely as possible. At Bugas-Holding, the goal was to locate items within about 5 mm accuracy. The 1 meter by 1 meter grid system assigned to each site is one tool to do this, but a site datum (control point for measurements) is also used to keep track of objects in necessary detail.
Refitting of bone fragments shows that the grease-rich distal ends of long bones were moved from Hearth 2 to Hearths 6 and 7. These two hearths also see a higher frequency of bighorn sheep bones.
All of the hearths at Bugas-Holding show ashy piles on the same side of the hearth. What would cause this? Likely wind. Much like today, when cleaning out a fire, you wouldn't put the ash upwind of the occupants because it would just blow back at you. Depositing the ash down-wind would clear it out of the hearth and save the occupants from getting covered in ash. Since all the hearths exhibit the same pattern, archaeologists infer that the hearths were located outside of any dwellings where wind direction has less impact on hearth fires.
In addition to canid (dog or wolf) tooth marks on bones such as the vertebra from the dump, Bugas-Holding has 6 canid bones at the site, four of which were modified into tools and ornaments.
Superposition is an important principal in archaeology. According to superposition, the oldest layers of a site are at the bottom and the younger layers are at the top (see 48PA201 for more). This is important when understanding Hearth 5. Which came first, the elk antler, vertebral column, or hearth?
Knowledge of animal behavior is essential for interpreting the archaeological record. At Bugas-Holding, MNI (minimum number of individuals) tells us there are at least 15 bison, 14 bighorn sheep, 2 elk, and 1 pronghorn at the site. Animal behavior can help us learn how these individuals were procured.
Take the two most common animals at the site- bison and bighorn sheep. During the winter, bighorn sheep congregate into larger herds that take shelter from severe winter weather in sheltered valleys, like the Sunlight Basin. Bison, however, disperse from their large herds into smaller groups during the winter. The inhabitants of Bugas-Holding likely procured bison through encounter hunts because of these smaller herds. The bighorn sheep would have been easier to kill in mass in larger groups. Sheep traps in the area make this a real possibility. While these behaviors would have made bighorn sheep a more available food source for the Bugas-Holding site inhabitants, just one adult bison can provide as much meat as 4-5 bighorn sheep.
Collecting without a permit
Not covered by PRPA, you can collect common invertebrate or plant fossils on public lands but the amount cannot exceed 100 lbs a year and must be gathered by hand (without the use of tools). Additionally, you cannot sell the fossils collected.
Many bison bones occur in archaeological and/or cave contexts, are protected under ARPA and Federal Cave Resources Protection Act (FCRPA), and can only be collected by qualified researchers with an authorizing permit.
Bison bones occurring in sediments or ice (outside of caves or archaeological context) often qualify as vertebrate paleontological resources under PRPA, and can only be collected with research and collection permit of the requisite federal land management authority.
Best Practice – treat bison bones as natural/cultural resources protected by ARPA/FCRPA/PRPA.
Collecting the remains of organisms like vertebrates, which include mammals (like bison) and reptiles, requires a permit from the Federal Government. Studying vertebrate fossils is important because it gives us and understanding of what past ecosystems may have looked like before human involvement.
Passed in 2009, the Paleontological Resources Preservation Act is similar to the Archaeological Resources Preservation Act, but it protects paleontological resources, like fossils. Fossils are the remains of plants and animals that once lived in the area and are preserved in sedimentary rock.
Paleontological Resources Preservation Act
Leave it in place
Leave it in place! The original context of archaeological and paleontological resources can yield valuable information, not all of which is apparent to the naked eye. Record where you found it—use GPS, take a photo of setting, make notes.
Report anything you find to the proper authorities.
When You Find Something
Each public lands entity (the Forest Service, BLM, Bureau of Reclamation, etc.) all have archaeologists on staff. These are the people to contact when you find something on public lands in the Bighorn Basin.
Kyle Wright, Shoshone National Forest Archaeologist, kyle.d.wright[@]usda.gov
Michael Stites, Bighorn National Forest Archaeologist, michael.d.stites[@]usda.gov
Kierson Crume, Bureau Land Management, kcrume[@]blm.gov
Wyoming Historic Preservation Office (SHPO), https://wyoshpo.wyo.gov/
Welcome to the Wyoming State Historic Preservation Office!
Removing one piece of a site is like taking a piece from a puzzle. Over time it gets harder and harder to see the big picture.
Even the Soil is Important
As technology advances so too does our knowledge. Did you know that the soil surrounding archaeological resources can contain information in the form of pollen on the plant life during that time? This information can help us learn about the climate, helping archaeologists make more informed inferences about the past. But wait, there's more! Scientists can now extract DNA from soil. Known as "eDNA" or environmental DNA, this can help us learn about early hominids, extinct animals, and more! These leaps in technology cause archaeologists to change the way they excavate sites and make it even more important for a portion of the site to be left untouched.
Passport in Time
Passport in Time is a project started through the Forest Service that now includes the BLM and HistoriCorps. Through Passport in Time volunteers work with professionals to help with things like archaeological survey, restoration, research, and more!
Site Stewardship Program
The Wyoming Site Stewardship Program is run through the Historic Preservation Office. Trained volunteers work with professionals to monitor cultural resources throughout the state.
Channel your passion for the past by volunteering! Here are just a few programs that always welcome volunteers. Keep in mind, you are the eyes and ears of your communities!
A cultural resource is anything that is evidence of past human activity. Cultural resources can take the form of artifacts, structures, rock art, and more. Even landscapes that have been altered or feature prominently in a belief system or way of life can be a cultural resource. Sites sacred to different Native American tribes would be considered a cultural resource. Cultural resources sometimes have special laws that govern their use. Learn more here.
The Bison Project
Staff took up to 26 measurements of each cranium, depending on completeness (photograph left). These measurements were established by a 1947 paper written by Morris Skinner and Ove Kaisen (below).
A project like this requires the expertise and skills of many different people. The Museums is lucky enough to have access to just such a group of people! This project was suggested by Meeteetse Museums Board President, Dr. Lawrence Todd. Director of Education and Programs, Amy Phillips, and Dr. Ken Cannon of Cannon Heritage, Inc. were the co-Principal Investigators on the project. Measurements were conducted by Amy Phillips and Director of Collections, Alexandra Deselms.
The team was advised by a group of scientific advisors consisting of Jason Baldes (Executive Director, Wind River Native Advocacy Center), Dr. Chris Widga (Head Curator, Gray Fossil Site and Museum, East Tennessee State University), Dr. Jeff M. Martin (Director of Research for the Center of Excellence for Bison Studies at the West River Research and Extension Center, South Dakota State University in Rapid City) as well as the formerly mentioned Dr. Lawrence Todd (Colorado State University, Emeritus) and Dr. Kenneth Cannon (Cannon Heritage Consultants). The advisors were interviewed for a season of the Meeteetse Museums' podcast "Meeteetse Stories" which can be found wherever you listen to podcasts.
As part of Wyoming’s Archaeology Awareness Month in September 2020, the Meeteetse Museums introduced the “Bison of the Bighorn Basin” project. Though wild bison have been absent from the Basin for over one hundred years, signs of their presence are still found throughout the area. The most iconic of these is the cranium. Bison crania are found throughout the Bighorn Basin decorating fences, barns, gates, and fireplaces. The bison cranium is a record of that individual’s life, giving us insight into the past.
To gather this information and learn more about the geographic Bighorn Basin's ecological past, the Meeteetse Museums sent out a call for anyone with a bison cranium found in the Basin to bring it to the Museums for measurement. Over the course of the project, the Museums measured 106 bison crania!
This side-by-side comparison, courtesy of Yukon Palaeontology Programme, Yukon Government, shows the left humerus of a Bison priscus (top) beside a Bison bison (bottom). Bison priscus, also known as the steppe bison, were not as large as Bison latifrons.
Bison latifrons lived in forests and woodlands throughout North America including Florida, Texas, and California. This species grazed at eye-level and its primary food source would be trees and shrubs. Bison latifrons is thought to have been similar to modern moose in that they were largely solitary and possibly territorial animals. At the shoulder latifrons stood 8 foot tall and had horns with a spread ranging from 5 to 7 feet. Notice on this 3D scan from the Idaho Virtual Museum that latifrons has a particularly large first cervical vertebra. The wing-like features on the vertebra are muscle attachments, allowing the bison to support the weight of its horn cores. This massive species would have weighed approximately 2,000 pounds when full grown and had a life expectancy of roughly 14 years.
The bison measured during this project were compared with metrics (measurements) from a national dataset gathered by Dr. Chris Widga, head curator at the Gray Fossil Site in Eastern Tennessee. The comparison revealed that the Bighorn Basin bison are morphologically modern. This means the bison lived within the last 3,000 years, before the population-bottlenecking event of the late 19th century. To learn more, the Project radiocarbon dated 23 of the 106 crania measured during the project.
What We Learned
Stable Carbon Isotope Analysis
Stable Nitrogen Isotope Analysis
With funds from the George C. Frison Institute, Buffalo Bill Center of the West Fellowship program, and private donations, the Meeteetse Museums sent 23 samples to John Southon at the University of California, Irvine W.M. Keck Carbon Cycle Accelerator Mass Spectrometer Lab for analysis. The majority of bison radiocarbon dated (73.9%) likely lived in the 1700s while the rest (26.1% ) are even older. This sample spans some interesting periods of change.
First, between the mid-1200s to the early 1800s AD the Medieval Warming Period ends, and the Little Ice Age begins. Second, our data set has bison from both before and after the reintroduction of horses to North America. Third, all the radiocarbon dated bison pre-date the population bottlenecking event of the 19th century. And finally, these bison also predate intensive, sedentary settlement of the Bighorn Basin by at least 75 years. How did bison in the Bighorn Basin respond to these changes?
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C4 plants are more competitive than C3 plants during periods of stress, especially during periods of drought. Their stable carbon isotope values range from -9% to -16%. C4 plants thrive in warm summers accompanied by adequate precipitation. Unlike C3 plants, the growth of C4 plants correlates with mean annual precipitation (MAP) and mean annual temperature (MAT).
As generalist feeders of grass biomass, we expect bison stable carbon isotope values to reflect a mixture of the C3 and C4 plants available in their range. Stable carbon signatures from this sample indicate a diet of largely C3 grasses. This is expected considering the specimens from the Project are from mostly high altitude and latitude sites.
Bison are sexually dimorphic which means male bison are larger than female bison in a measurable way. Five measurements were used to determine the likely sex of each bison.
Bison use their horns much like humans use jewelry or clothing. For them, their horns are social signals. Large horn cores make male bison effective at gaining breeding rights and are representative of their overall health. Since male bison are the ones who initiate breeding, they are the ones who have to signal their prowess. This means male bison will have a greater measurement from the tip of one horn core to the tip of the other,
Legislation & Agreements
Yellowstone National Park
Despite being endangered in the early 20th century, today bison are thriving. As of 2016, the bison became the United States’ national mammal. It’s a tribute to the uniqueness of the species. Bison are the only large-game animal native to North America which can be raised on ranches without a permit. They also live in conservation herds like those at Yellowstone National Park and the Wind River Reservation.
Bison in Lamar Valley, NPS.
"Legal Writing" by Dave Wilson Cumbria is marked with CC BY-NC-ND 2.0.
Today bison are returning to their former ranges through the efforts of people like Jason Baldes, Eastern Shoshone. On the nearby Wind River Reservation, the Eastern Shoshone Tribe has 66 buffalo, and the Northern Arapaho Tribe has 32, as of October 2021. For Baldes and the Eastern Shoshone, the goal is to eventually allow the tribes to return to traditional subsistence ways after an absence of upwards of 100 years. The return is important for tribal sovereignty and tradition but also the land.
"...education around buffalo is very important for our young people because on our reservation, the majority of our population is under the age of 30. And we have to be able to create leaders on the Reservation that are knowledgeable about our history with buffalo but also our history with our language, with our culture, with governments, with our environmental issues. And so, this buffalo institute or buffalo education center is being implemented and created so that we can teach our young people how to be grounded in our cultural ways so that we are grounded as Tribal Leaders in the future." - Jason Baldes, Season 2 Episode 4 "Meeteetse Stories"
Bison are what is known as a keystone species. Their presence on the landscape affects many other organisms, both plants and animals. As bison find food, a behavior known as foraging, they aerate the soil with their hooves. This aeration aids in plant growth and is a behavior mimicked today for the growth of grass in residential and commercial lawns. As bison graze, they also distribute seeds, spreading native plants across large tracts of land while also providing food for other animals including birds. Bison also roll in the soil, creating wallows or areas of compacted soil which are better suited to retaining water. These wallows are crucial for amphibians and other wetland species.
Many tribes of the Great Plains relied heavily on bison for their food, clothing, and tools. In the mid-1800s as bison became increasingly scarce on the landscape and tribes were forced onto reservations, the tribes were forced to consume rations provided by the United States government. These foods included things such as flour, tea, coffee, salt, beans, and beef. These new foods were nutritionally inferior to the tribes traditional foods and ultimately resulted in health problems including malnutrition, diabetes, and more.
The reintroduction to tribal lands is not just about the return of a relative and the spiritual health that return brings. The return of bison to the land allows for food sovereignty.
“Food sovereignty is the right of peoples to healthy and culturally appropriate food produced through ecologically sound and sustainable methods, and their right to define their own food and agriculture systems. It puts the aspirations and needs of those who produce, distribute and consume food at the heart of food systems and policies rather than the demands of markets and corporations.”
– Declaration of Nyéléni, the first global forum on food sovereignty, Mali, 2007
Food sovereignty helps to solve the health issues created by the sudden reliance on rationed, nutritionally inferior foods and allows Plains Tribes to return to cultural food practices.
Legislation and Agreements
"Legal Writing" by Dave Wilson Cumbria is marked with CC BY-NC-ND 2.0.
On September 24, 2014 the following nations signed a document pledging their commitment to returning the buffalo back to its former ranges. Those nations were: Blackfeet Nation, Kainai/Blood Tribe, Siksika Nation, Piikani Nation, the Assiniboine and Gros Ventre Tribes of Fort Belknap Indian Reservation, the Assiniboine and Sioux Tribes of Fort Peck Indian Reservation, the Salish and Kootenai Tribes of the Confederated Salish and Kootenai Indian Reservation, and Tsuut’ina Nation. In 2019, the Eastern Shoshone joined the treaty and today a total of 31 signatories have signed the document known as “The Buffalo: A Treaty of Cooperation, Renewal and Restoration.” The signatories meet annually to discuss the progress that has been made and determine next steps of action.
The Buffalo Treaty
“Existence is a 'spider web' network of relationships in the Indian mind world. That mind world forever is in search of regular patterns that give existence to our people through our cultural life ways. The Buffalo is keystone to the maintenance of life ways of cooperation, kindness, renewal, and sharing amongst and between peoples.”
The Bison Treaty
H. R. 5153
In December 2020, the Indian Buffalo Management Act was passed by the House of Representatives. The Act acknowledges the importance of the buffalo to many Native American tribes and works to assist the management of buffalo and buffalo habitat on Indian lands.
Indian Buffalo Management Act
For hundreds of years, the United States government tried to remove the bison as a way of wiping out Native Americans. Through this act, the government signals its intention to promote tribal ownership of bison on tribal lands.
H. R. 2098
In 2016, the bison became the United States of America's national mammal. The Act acknowledges the relationship between Indian tribes and the bison, their continuing efforts in restoring bison to the landscape, and the complex history of bison in North America.
National Bison Legacy Act
What do you think the adoption of the bison, with its complex history and near-extinction, as the National Mammal means for the future of bison reintroduction and tribal sovereignty?
Bison are a native species in the Park and the surrounding ecosystem, known as the Greater Yellowstone Ecosystem. Learn more about their long history in the area here.
What is brucellosis and why does it relate to the Yellowstone National Park herds?
New research has been conducted by the Park along with other partners to learn about the migration of their bison. Learn more!
Bison in Yellowstone National Park
Bison may be icons of the United States’ first national park, but the Park herd is important for more than just their good looks. Since the bison in Yellowstone are genetically-pure, they are important for starting additional conservation herds and reintroducing bison to the landscape. They are also living in a very large, unfenced area which means studying them can give us clues about how bison of the past may have behaved.
"Conserving the North American bison" courtesy of U.S. Geological Survey.
Brucellosis is a disease that can cause abortions and infertility in bovines, which includes bison and cattle, as well as loss of weight, decreased milk production, swollen joints, and more. The disease is not native to North America but was introduced along with domestic cattle. Brucellosis has been eliminated from 48 states, existing in the continental United States only in Yellowstone National Park. The disease can be transferred through feces and is also carried by elk. Unlike bison, elk, managed as wildlife, are allowed to move freely between Yellowstone and surrounding areas and have been documented to transfer the disease to cattle. Cattle are susceptible to the disease, which can result in loss of profit for local ranchers. Before bison leave the Park for introduction in other herds, they must be certified brucellosis-free. This lengthy process requires the animal to be removed from the herd for anywhere from one to two years.
Learn more about how the Park certifies bison as brucellosis-free here:
Bison Conservation Transfer Program - Yellowstone National Park (U.S. National Park Service)
[i] “Brucellosis and Yellowstone Bison,” Animal and Plant Health Inspection Service, United States Department of Agriculture, accessed December 13, 2020, https://www.aphis.usda.gov/animal_health/animal_dis_spec/cattle/downloads/cattle-bison.pdf.
[ii] Del Hensel, “Brucellosis and Bison,” Bison World 22, no. 3 (July/August/September 1997): 32-33. https://www.bisoncentre.com/resources/resource-library/advanced-bison-information-producers/diseases-bison/brucellosis-and-bison/. Online article reprinted by author.