That picture has changed dramatically today. Montana is one of the last places where bison live, most notably in Yellowstone National Park and at the National Bison Refuge near Moiese. Bison are the most massive herbivores, or plant eating animals, in North America. Males can weigh up to a ton, and females weigh in at about 1,000 to 1,200 pounds. As you can imagine, these are not animals you want to upset or frighten.
Bison are very unpredictable, and have even been known to charge vehicles.
You might be fooled into thinking their massive size makes them slow. Bison usually travel in herds, with the exception of older males who are solitary. These bachelors join the herd only at breeding time to fight with the younger males for breeding rights. Females will leave the herd and find a secluded place for birthing, then rejoin the herd after the calf is about four days old. When bison roamed the entire great plains they migrated hundreds of miles in the spring and fall of each year, but now because of their limited habitat they migrate very little.