American Bison Fact Sheet

The Crane Trust works to protect and maintain critical habitat for the endangered whooping crane, sandhill crane and other migratory birds along the Platte River. On nearly 10,000 acres of land we research, develop, and implement land management practices that maintain native environments and provide habitat for cranes and the diverse wildlife Fast Facts present throughout the seasons. In 2015, after a 150 year absence, the Scientific name:Bison bison Crane Trust acquired a herd of rare genetically-pure bison to roam the Height: up to 6½ ft. property and return to their role as a feature of the prairie ecosystem. Weight: 700 to 2,000lbs Length: 7 to 12 ft. Bison in Decline Number of Calves: 1 or 2 The American bison (Bison bison) has been eliminated from much of the Mating: Late July to August wild. From an estimated population of 30-60 million ranging from northern Calving: April to May Mexico to Alaska only a few hundred thousand were left by 1870, and Longevity: 12 to 22 years nearly all were eliminated from this area. The population plummeted due Habitat: Mixed & short grass prairie mostly to hunting, for food, hides, and space. Top Speed: 35 mph The hunt accelerated in 1879, which has come to be known as the 2015 Calving: 11 calves Great Slaughter, to not only exterminate the herds for consumption and marketing, but also to take away the major food source for Native American peoples on the Plains as a way to subjugate them. By 1889, there were as few as 1,000 bison left; only 85 of those bison roamed free.

Conserving the Largest North American Land Animal With a shift in perception toward bison, the realization that they are a keystone species and countless conservation efforts, the bison has bounced back to approximately 30,000 in the wild, managed in parks and refuges. However, only a small portion of bison today are genetically pure, due to the fact that many of the remaining herds were bred with cattle.

There is debate about how the cattle genes affect bison; some say that the cattle genes affect the bison’s resilience to winter and scarcity. Despite extensive studies analyzing bison DNA – which remains a challenging area of research – scientists are still working to understand how cattle genetics Top: More than 50 bison make their home on the Crane Trust lands. Photo by R. McLean may change bison herds. Bottom: Dominant male bison. Photo by R. McLean Genetic Diversity One problem that can arise when populations become small is genetic diversity. The Crane Trust works to make sure that any new bison brought into the herd is genetically pure, but also that bison cannot mate their close relatives. Preserving the integrity of this species is one of the highest goals. For example, the Crane Trust herd has ancestry linking them to the Yellowstone National Park herd, which is the only herd in the United States that has continuously roamed wild. Cattle genetics are not a part of this herd and will not be introduced in the future.

Crane Trust • 6611 W Whooping Crane Drive • Wood River, NE 68883 • cranetrust.org Life Cycle of a Bison Each spring new calves are brought into the herd in April or May, but occasionally late summer caves are born as well. These calves are a cinnamon orange distinct from the chocolate brown of their parents. Around this time the herd will be shedding their large dark winter coats for a lighter fur.

Then with the end of summer available females will be fought for in what is known as the annual rut. At this time you will see males go head to head in the most aggressive form of bison socialization: head-butting, mounting, and long stares. In the end males will mate with females that accept them; often guarding one mate until after her estrus then moving on to another female.

Around the end of the rut the herd will grow their winter coats, and the calves of the season will turn brown and begin to sprout their horns. These coats protect them from the chill of winter and the frost that comes with it. In times of deep snow bison will use their massive heads to plow a trail while searching for vegetation to eat. This cycle then begins anew with the regrowth of the spring plants.

Role on the Prairie Bison graze heavily on native grasses and disturb the soil with their hooves, allowing many plant and animal species to flourish. They nourish the entire grassland community of the Great Plains and in turn, the community nourishes them with grasses, sedges, and other native vegetation to sustain the giants of the Plains. For example, upland sandpipers, tiger salamanders, and Missouri goldenrod have historically been found in ecosystems bison helped create.

Historically, these animals would have roamed the prairies finding areas of suitable resources year-round. Wild bison move two to three miles a day and about 200 miles per year. These migrations were presumably north- Varying ages of bison. Top: New calves. Photo by Greg Wright south and east-west migrations and not necessarily to escape winter Middle: Yearling. Photo by R. McLean Bottom: A female and male adult. Photo by R. conditions as bison are well-suited to cold and snow. McLean

Bison: a social animal Bison are not cattle, and in watching herds it is very clear. These animals have an extensive social structure where every individual has a place in the hierarchy. Separating individuals from the herd causes extreme stress to the animals. However, mature males will often leave the females outside of the mating period.

Research at the Crane Trust The research possibilities are many, and currently we are researching: herd hierarchy and interactions, novel behaviors, stress response to handling, parasite loads, and how bison wallows impact vegetation. Long- term monitoring studies include the evaluation of bison-bird interactions, both direct and indirect, as a means of learning how the addition of this The Crane Trust Bison herd grazing in one of their historic grazer can benefit cranes and other migratory birds. pastures. Photo by R. McLean

Crane Trust • 6611 W Whooping Crane Drive • Wood River, NE 68883 • cranetrust.org