Bison population in Wyoming state throughout the years

Since 1986, over 10,300 bison have been killed as they crossed northern border of Yellowstone into Montana

Bison can live 12 to 15 years, and the males can weigh as much as 2,000 pounds, making them the largest land mammal in North America. During the mating season, which begins in August, males fight fiercely for females, and often inflict serious injuries with their horns on each other. Sometimes they die from their injuries.