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The Resilient Spirit of Yellowstone Bison

By April 17, 2020No Comments
Bison walking through Soda Butte Creek, a Tributary of the Lamar River.
Bison in Soda Butte Creek, a tributary of the Lamar River.

Story & photos by Debbie McCulliss

Photographing bison in Yellowstone National Park is on many photographers’ bucket lists. These magnificent mammals are certainly photogenic, but learning a bit of their history, and the role they play in the ecosystem gives us a deeper understanding of both bison—or buffalo as they are known to many people, and their environment, as well as imbuing our photos with additional layers of meaning.

On my first winter photography trip to Yellowstone this past February, I became fascinated with our national mammal and the symbol of the American Wilderness and West. As herds of bison, which are each about six feet tall and weigh between 1,000 and 2,000 pounds, swung their heads from side to side to plow snow, sometimes as deep as four feet from foraging patches to graze, I couldn’t help but stare at their protruding shoulder hump. I was in awe of the muscles that allow them to swing their neck from side to side, their shaggy, long, dark-brown winter coat, and their tails. Both males and females have relatively short horns that curve upward, with the males’ averaging slightly longer. Despite their size and weight, bison are excellent swimmers, can run up to 35 miles per hour (three times faster than humans), and can jump over objects about five feet high. They have excellent hearing, vision, and sense of smell, and are agile. A bison can pivot quickly when fighting predators, such as wolves or grizzlies, that attack from behind. For all of these reasons, staying a safe distance is crucial when photographing and viewing wild animals. Their life expectancy is up to 20 years in the wild, and even longer in captivity.

Yellowstone bison have shown me why they are symbols of strength, stamina, survival, unity, and a wild spirit, especially in this protected land of unpredictable, harsh weather and wind.

Yellowstone snowfall totals in winter can be upwards of 100 inches, and temperatures can drop well below zero. When I was there, temperatures reached a low of -22 degrees Fahrenheit. Adaptations that help bison survive these freezing temperatures include their conserving of energy by slowing down their metabolism, decreasing the amount of time spent foraging and feeding, and generating internal body heat through digestion.

Photo Adaptations

I had to make quite a few adaptations that helped me stay warm while photographing the bison in cold and snowy conditions, including layering my clothes, wearing a hat and liner gloves or winter gloves made for photographers, using a remote shutter release, and using disposable hand and feet warmers. Planning ahead and being prepared were key to making my winter Yellowstone experience successful.

There is something for every photographer at Yellowstone in winter—capturing high-contrast or dramatic snow scenes, the animals surviving in harsh conditions, a variety of textures, and simplicity—even stunning black and white images. Yellowstone’s ecosystem allows for it all.

I found it helpful to use a tripod, shoot in raw, on manual and matrix metering, using the viewfinder more often than Live View to avoid having an LCD screen freeze at low temperatures, and experiment with a variety of focal lengths, exposure settings, and white balance settings. My goals included keeping the histogram close to the right, but not touching; having the snow on the ground have a slight blue cast with neutral highlights, rather than having it appear yellow; capturing falling snow rather than streaked snow; including the landscape, rather than just taking a portrait shot; and capturing the animals behaving naturally in their habitat.  

Adaptations that helped me protect my camera included frequently wiping stray snowflakes from my Tamron 150-600 F/5-6.3 lens or moisture in my viewfinder with a clean microfiber cloth, using a lens hood to avoid lens flare (fresh snow can be highly reflective), tilting my lens down when not photographing, keeping the lens cap on when not in use, protecting my Nikon D850 with a rain cover, and having plenty of spare batteries that I kept warm inside my coat. Cold weather drains batteries quicker of their power and efficiency so I was careful to keep an eye on my battery level and if I needed to switch out batteries. After each shoot, to prevent sudden dramatic temperature changes that would cause condensation, I kept my gear in an airtight plastic bag in the car.

Bison don’t have to worry about dramatic temperature changes. They have excellent winter insulation due to their thick coats. When snow accumulates on them, it doesn’t melt despite the heat of the bison’s skin. During daily snowstorms, we saw several herds of bison hunker down, face first into the storm, while waiting for it to pass. Lack of or quickly changing light was one of the biggest challenges in photographing the bison. In near white out conditions, the wind necessitated a high shutter speed.

Bison hunkering down in the snow and fox on the hunt.
Bison hunkering down and fox on the hunt.

Other animals, including elk, moose, pronghorn, big-horned sheep, bear, foxes, and wolves share the habitat with the bison. In photographing any wildlife, it helps to know your subject and any predictable behavior.

In between storms, we witnessed several traffic jams caused by the movement of the herd. While keeping a safe distance from both bison and cars, we stopped to photograph a few.

Bison sauntering down the road .
Bison sauntering down the road.

The Yellowstone Herd

Yellowstone contains the nation’s largest bison population on public land. These bison are unique in that they are among the few bison herds that have not been hybridized through interbreeding with cattle. In other words, these bison are free of cattle genes. Currently, about 4,800 healthy wild bison roam freely year-long over the expansive landscape of the Lamar and Hayden Valleys, feeding primarily on grasses and sedges and other alpine meadow grass-like plants. Their numbers have been increasing each year.

Bison have contributed greatly to the unique Greater Yellowstone Ecosystem, which is one of the largest nearly intact temperate-zone ecosystems on earth. The quality of this landscape is the result of thousands of years of volcanic activity and many naturally caused forest wildfires, that have also contributed to the natural regeneration of its forest, including the dominant lodgepole pines.

While bison are migratory animals, to where they head depends on the quality and quantity of food and winter snowpack. As snow and dense snowpack accumulates in Yellowstone, bison migrate from their summer ranges to lower elevations for winter grazing. In February we photographed them sauntering down the road or wandering around the hydrothermal areas and along the Madison River and Gardiner Basin. Using a neutral density filter might have provided some control over exposure, by helping minimize glare from the snow and ice-covered surfaces in frigid temperatures, especially on blue-sky days.

Several bison in a snowy clearing  enjoying the sunshine.
Bison enjoying the sunshine.

Bison in Yellowstone are divided into two subpopulations—the Northern and Central herds. The northern herd breeds in the Lamar Valley and surrounding areas, while the central herd breeds in the Hayden Valley.

Bison have lived in Yellowstone continuously since prehistoric times. Thirty to sixty million bison once roamed in vast herds across much of North America—from Alaska to Mexico and from Nevada to the eastern Appalachian Mountains (National Bison Association). On their paths, they helped form the foundation for entire, vast ecosystems.

The millions of acres of Yellowstone ecosystem, which spans across parts of Wyoming, Montana, and Idaho, has been protected since March 1, 1872, when President Ulysses S. Grant signed the Yellowstone National Park Protection Act, primarily to protect geothermal areas that contain about half of the world’s active geysers. This action inspired the birth of the world’s first national park. Yellowstone National Park is named after the river that runs through it.

Bison, History & Conservation

Despite this protective act, the United States has a long and varied history with the bison, which has been brought about by drought, hunters, war between settlers and indigenous people, trains, and Brucellosis disease, a non-native, bacterial disease that has been traced back to exposure to infected livestock of European settlers. Brucellosis is a contagious, infectious, communicable, and costly illness that causes lowered milk production, aborted calves, and reduced breeding efficiency, as well as great pain and suffering, primarily in cattle, bison, elk, and deer. It is transmissible to humans, most commonly by way of eating or drinking unpasteurized or raw dairy products and is difficult to quarantine.

In the 1800s unregulated market hunting contributed to the near extinction of the Yellowstone bison. In the 1840s, a mass slaughter of bison on the Great Plains began and plains culture was forever changed. As settlers pushed west, not only was there a reduced animal habitat, but a lucrative trade for bison skins and hide and meat evolved. Native American populations who thought bison were a powerful spiritual symbol, relied on bison for food. When horses and guns were introduced to their culture, they provided greater mobility and increased killing efficiency. By the end of the Civil War in 1865, there still might have been as many as 15 million bison.

However, when the Transcontinental Railroad came about in 1869, work crews needed to be fed. A practice of “hunting by rail” robbed Native Americans of their food supply and hides for clothing and shelter. Railroad operators became frustrated at how long it took for a large herd of bison to cross the railroad tracks, something that could delay a train for hours. By the late 1800s, fewer than 1,000 bison remained.

Even though commercial hunters abounded, it was a museum hunter who began the comeback of the bison population. In 1886 William Hornaday, the Smithsonian’s chief taxidermist, went on an expedition to Yellowstone to hunt and stuff an entire family of bison for a display at the National Museum, especially since it was believed that bison would soon be extinct. What he found was only a few animals and evidence of the mass slaughter of bison by market hunters. He brought back 15 bison from Yellowstone to live on the National Mall and dedicated the rest of his life to the conservation of bison in the wild and the education of the American people about these amazing animals. He became one of America’s first conservationists and his pioneering efforts led to the creation of the National Zoological Park as part of the Smithsonian (those 15 bison were among the initial residents). The zoo’s mission: to preserve, teach, and conduct research about the animal world. The American bison was among the first species in the world to arouse human concern over its imminent extinction.

By 1902, poachers had reduced the Yellowstone herd to about two dozen wild animals. In 1905, Hornaday formed the American Bison Society with his friend Theodore Roosevelt to round up surviving bison with the intention of creating more wild herds in an effort to repopulate the plains. Bison from private existing herds were used to establish a northern Yellowstone herd. Recovery efforts expanded into the mid-20th century, with a resurgence of roughly 31,000 animals today, mostly restricted to a few national parks and reserves.

However, brucellosis was still common in the 1950s. Since the mid-1950s, the United States Department of Agriculture’s National Brucellosis Eradication Program, a cooperative effort between the federal government, the states, and livestock producers, has nearly eliminated brucellosis in domestic livestock. And they remain committed to maintaining a viable and free-roaming bison herd in Yellowstone. There is no cure, but a vaccine (RB51) was approved for cattle back in 1996.

Management challenges of today’s bison herds are plentiful. Climate change and an abundance of tourism are among these challenges. Outside the boundaries of Yellowstone, bison are constrained from migrating or dispersing due to concerns of brucellosis transmission. Determining if an animal is truly brucellosis-free, which requires knowledge of the animal’s age, sex, and reproductive status, requires months to years of quarantine.

The National Park Service has established policies for bison that were developed with federal, state, and tribal agencies to prevent conflicts with ranchers and outside of Yellowstone activities. People don’t want bison killed. Hunters and ranchers want the park’s population of bison controlled from overgrowing so that bison have enough space to roam, and there is a lowered risk of overgrazing the park with resultant insufficient food. Officials want the quarantine program expanded. And Montana Indian tribes want to repopulate their reservations with surplus disease-free bison herds from Yellowstone. For example, a partial request was granted in 2019 when 55 male Yellowstone bison were transported to Fort Peck Indian Reservation in Montana, home to a quarantine facility. With these latest additions, their bison herd number almost 400, although most of the bison will be sent to other tribes in Montana and Wyoming that want to grow their existing herds or establish new ones.

Also, in 2016, then-President Barack Obama signed the National Bison Legacy Act, designating the bison as our national mammal; this action showcases and reinforces wildlife conservation and brings increased attention to ongoing species recovery. The bison joins the bald eagle as an official animal symbol of the United States.

Despite our past mistakes and mistreatment of the bison, they are now getting the respect that they deserve. The protection and recovery of bison in Yellowstone is among the great triumphs of American conservation. Hundreds of people, including Native American tribes and other organizations, businesses, and campaign efforts, have helped to bring this species back from the brink of extinction. In the process, their efforts have also encouraged the support of endangered species and recovery of grizzlies, elk, trumpeter swans, bighorn sheep, and the reintroduction of a native predator, the grey wolf. 

Debbie McCulliss is a Colorado-based wildlife and nature photographer whose my work is represented in the Windfall Fine Art Gallery in Steamboat Springs.

She is a certified applied poetry facilitator and holds master’s degrees in nursing, science-medical writing and nonfiction writing. She came to photography after an unexpected fascination with the behavior of bald eagles. It didn’t take long before she fell in love with photographing a variety of wildlife and witnessing the strength, fragility, beauty and rhythm of nature. The more she learns, the bigger her photographic world becomes. 

With camera in hand, she travels the globe, mostly to colder regions, to capture images that speak to the heart. She believes that her photography speaks, not only for her but for people who can only imagine what it would be like to explore the world with freedom of mind and imagination. Her goal is to create memorable art that inspires conversation.

See more of her work at