How bison help shape the Northern Great Plains

Bison graze the grasses at different heights, providing nesting grounds for birds. They also roll around and pack down the soil in depressions in the ground known as wallows. Their wallows fill with rainwater and offer breeding pools for amphibians and sources of drinking water for wildlife across the landscape.

Rain only comes in bursts in the Northern Great Plains, forming vast networks of wetlands in some regions. Pools formed by bison activity collect water above ground for longer periods of time, more broadly across the landscape. Without these wallows, water would only be found in naturally occurring streams and ponds.

Wallows help plants, too, by providing a specialized habitat. Several medicinal and rare plants—and plains animal habitats—rely on these depressions.

Birds such as long-billed curlew use bison droppings as camouflage. They build nests nearby in patterns that mimic bison droppings. Birds also use bison fur to line their nests. The dense fur provides much-needed warmth and fosters greater nesting success.

Prairie dogs prefer to nest in areas that bison heavily graze. Short grasses provide ideal areas to dig burrows and serve as a source of food.

The bison’s massive heads and shoulders allow them to plow through deep snow, making highways for animals such as pronghorn antelope and elk in the winter months. Their foraging activities in snow also make it possible for other animals to reach grasses that would otherwise be unattainable.

For millennia, tribal communities in the Northern Great Plains depended on bison for food and shelter. People used every part of the bison for a variety of specialized purposes, including food, tools, musical instruments, and shelter.

WWF works with tribal partners and national parks to help protect this vital species. Our goal is to establish five herds of at least 1,000 bison each by 2025, providing an opportunity for greater genetic diversity and healthy plains bison populations.