Heavy snow doesn’t usually bother bison, though truly extreme storms can pose a danger. Their thick fur is so insulating that snow often piles up on their backs without melting. In winter, they grow a dense, woolly undercoat beneath longer guard hairs. This natural layering, along with thickened skin and fat beneath the hide, traps body heat and blocks out most of the cold.

American bison have been seen standing through blizzards covered in snow that stays frozen, showing how little heat escapes. When they move, they can often shake off the snow like powder. They can handle subzero temperatures on open range.

When snow blankets the landscape, bison rely on a built-in tool to uncover food: their massive, muscle-powered head. Their distinctive shoulder hump supports strong neck muscles that help them swing their heavy head from side to side, plowing through snow with force. Unlike most hoofed animals that mainly paw at the ground, bison frequently sweep snow aside with their face, clearing access to buried grasses.​

This technique is surprisingly effective. Bison have been observed foraging through snow around a meter deep, roughly 3 to 4 feet, using this method in some areas, especially where snow has drifted. Beneath the snow, they feed on dry grasses and sedges. These are not especially nutritious, more like tough winter roughage, but bison make do by eating whatever vegetation remains.​

They often seek out wind-blown ridges or sun-exposed slopes where snow is thinner. In tougher conditions, they may migrate to lower elevations or more open prairie zones to keep food within reach. They can break through crusted snow or ice with their strength.

Winter on the northern plains is no time for a bison to be sprinting or burning extra calories. To get through the cold months, they slow both their movement and metabolism. Bison travel less and move deliberately to conserve energy. In freezing temperatures, they need less food than in summer, and by staying less active, they reduce how much cold air they breathe in, easing the demands on their heart and lungs.

Since winter forage is low in nutrients, bison cannot simply eat more to compensate. Instead, they rely on an efficient digestive system. The grasses they consume stay longer in the rumen, fermenting like a slow cooker. This process breaks down the material, releases more calories, and generates internal warmth as a by-product.

With help from fermentation and stored body fat, bison can endure long, cold months. It’s normal for them to lose some weight during winter. A female bison, for example, might shed about 10 percent of her body weight by spring. But once fresh grass returns, so does the weight.

When an Arctic blast rolls over the plains, bison face into the wind and snow, often standing shoulder to shoulder and sometimes bedding down to reduce exposure. Their thick coats block much of the cold, and by facing forward, they help prevent gusts from getting under their fur. Their broad foreheads take the brunt of the storm, and with heads down and humps raised, they become a kind of natural barrier.

While extreme weather can still take a toll, they tend to fare much better than domestic cattle, which often struggle without shelter. Bison are built for these conditions, and their adaptations give them a clear advantage.

They also use the terrain to their advantage, settling in gullies, behind trees, or along slopes for added shelter. On the coldest days, a bison might stay still for hours to conserve warmth. From a distance, they can appear frozen in place, but they’re simply riding out the cold.

Bison are social animals, but their winter groups tend to be smaller than the large herds seen in summer, often just a few dozen or fewer. Even so, these compact groups provide warmth and protection. By standing close together, bison reduce wind exposure and can shelter calves or weaker members in the center. Herding also means more eyes and ears to detect danger, which is especially helpful when snow limits visibility.

Traveling as a group makes getting through the snow easier. The strongest bison often end up breaking trail, pushing through fresh powder so the others can follow more easily. In deep snow, they frequently walk single file, conserving energy by letting one animal do most of the work while the rest follow in compacted tracks.​

In Yellowstone National Park, bison follow ancient migration routes to lower elevations and sheltered valleys as snow deepens. These well-worn paths reflect how herds adapt to shifting conditions year after year.

They also have a clever solution for hydration. In cold months, bison often eat snow to help meet their water needs, even though melting snow internally does cost some energy. Their system can still use this water source effectively, letting them stay hydrated when rivers and ponds are frozen or hard to reach. If there is open water nearby, such as a spring or geothermal stream, they will find it. But in many winter situations, snow alone does the job well enough for them to get by.