Wind Cave bison herd facts for kids
The Wind Cave bison herd is a group of 250 to 400 American bison living in Wind Cave National Park in South Dakota, USA. This herd is special because it's believed to be one of only four herds in North America that are truly wild and have pure bison genes, meaning they haven't mixed with cattle. The other pure herds are found in Yellowstone National Park, the Henry Mountains bison herd in Utah, and Elk Island National Park in Alberta, Canada. The bison at Wind Cave are a type called Plains bison.
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The Story of the Wind Cave Bison Herd
Long ago, millions of American bison roamed across North America. Some experts think there might have been as many as 25 to 60 million of these huge animals! They were probably the most common large land animal on Earth. However, by the late 1880s, hunters had nearly wiped them out.
The Wind Cave bison herd began with 14 bison from the New York Zoological Society. Six more bison were brought from the Yellowstone Park bison herd. Later, in the 1960s, one male bison (a bull) joined the herd from Theodore Roosevelt National Park. The Yellowstone Park herd was very important because it was the only place in the United States where wild bison never completely disappeared. Because of this, many other bison herds, including the one at Wind Cave, got their start from Yellowstone bison. In turn, the Wind Cave herd has helped start other herds, like the Tallgrass Prairie bison herd in Kansas.
Where Bison Live: Their Home in Wind Cave
Wind Cave National Park has huge areas of grassy prairie. This is a perfect home for American bison.
Bison are large animals that live in herds and protect their young very well. They can run up to 35 miles (56 km) per hour and are surprisingly quick and strong. They can also be a bit grumpy! There aren't many animals that hunt bison in Wind Cave National Park. Large predators like brown bears, grizzly bears, and wolves are not currently found there.
Wind Cave National Park is about 33,847 acres. This might not be big enough for a healthy population of predators. However, the park is part of a much larger area of grasslands. Other big animals living in the park include elk, coyotes, bobcats, deer, and pronghorn. These other grazing animals don't really affect the number of bison in the herd.
Why Bison Genes Matter: Keeping Them Pure
The Wind Cave bison herd is special because its genes are considered "pure." This means there's no sign that these bison have mixed with domestic cattle. Most bison herds, both on private farms and in public parks, are not genetically pure. Genetic tests show that about 95% of bison in other areas have some cattle genes.
Even though American bison are a different species and genus from domestic cattle, they can still have babies together. The mixed-breed animals often look just like pure bison. So, you can't tell if a bison is pure just by looking at it. In the past, many ranchers purposely bred bison with cattle. It's also likely that bison and cattle mixed naturally when they lived in the same areas. Since they eat similar food and can live in similar conditions, they often shared the same land.
Most bison today come from just five herds that were saved when bison were nearly extinct in the late 1800s. These herds were part of experiments where they were bred with cattle. Because of this, cattle genes are now found in most bison populations.
In recent years, scientists developed tests to check the DNA of bison and cattle. They found that most private "buffalo" herds were actually mixed with cattle. Even many government-owned herds had some cattle DNA. With newer DNA tests, we now know that even more herds have cattle genes.
Out of about 500,000 bison on private ranches and in public herds today, only about 15,000 to 25,000 are thought to be pure bison, without any cattle genes. Important public herds that seem to be pure include the Yellowstone Park bison herd, the Henry Mountains bison herd (which started with Yellowstone bison), the Wind Cave bison herd, and the Wood Buffalo National Park herd in Canada.
A big study on bison genes by James Derr at Texas A&M University looked at how well bison are doing. He found that bison seem to be healthy, even though their numbers dropped very low in the past. The study showed that most state-owned bison herds had cattle DNA, except possibly the Henry Mountains herd. Most national herds, except Wind Cave and Yellowstone, also seemed to have mixed genes. As genetic testing gets even better, we might find that almost all bison have some cattle genes.
Another study by Wilson and Strobeck looked at how different bison herds in the U.S. and Canada are related. They also wanted to see if the bison in Wood Buffalo National Park and Yellowstone Park were different types of bison. Some people thought the Yellowstone bison might be "wood buffalo" or a special "mountain" type. The study found that Wood Buffalo Park bison were a mix of plains bison and wood bison, but mostly wood bison. However, the Yellowstone Park bison were pure plains bison. This is good news for the Wind Cave herd, since it got some of its bison from Yellowstone. The bison in Wind Cave National Park are also plains bison, just as expected.
The Future of the Wind Cave Bison Herd
By 1890, American bison had almost disappeared from their natural homes, except for the herd in Yellowstone National Park. Even that herd was very small, with only a few dozen animals. This raised worries about a genetic bottleneck, meaning there wasn't much genetic variety left.
Today, there are about 500,000 bison. But most of these are mixed with cattle and live on private ranches for meat. They don't roam freely across the plains like they used to. Some herds, like the Wind Cave bison herd, are free, but their roaming areas are limited. So, bringing back large bison populations isn't a sure thing. Because of these reasons, there are still questions about how to manage the Wind Cave Bison Herd in the future.
Since the Wind Cave bison are genetically pure and healthy, they can play a big part in bringing bison back to more areas. Groups and governments in the United States and Canada are working to return bison to their old homes. When moving bison to new places, it's very important to keep their genes diverse. This helps make sure valuable genes aren't lost forever. It's also important to prevent cattle genes from mixing into pure herds like Wind Cave's. The Wind Cave bison could really help with this effort.
However, there's a risk to the Wind Cave bison herd's genetic purity. The herd at Custer State Park, which is only a few miles away, does have bison with cattle genes. Bison from Custer State Park have even been seen wandering into Wind Cave National Park. So far, there's no proof that these bison have mixed with the Wind Cave herd. But many scientists believe extra care should be taken in the future to protect the Wind Cave herd's pure genes.
Unlike the Yellowstone Park bison herd, the Wind Cave bison herd does not have a disease called brucellosis. This disease doesn't seem to cause big problems for bison. However, it's used as a reason to keep bison inside Yellowstone National Park. It's also why the state of Montana allows hunting of Yellowstone bison if they leave the park. Since the Wind Cave herd is free of brucellosis, there's less reason to keep them confined. This means it should be easier to let their population grow and allow them to roam over a larger area if more land becomes available.
Images for kids
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Bison grazing on prairie grasses
