Close-Up of a Bison
Photograph by Sam Abell
With their large, sharp horns, bison are formidable foes. During mating season, bulls fight for the right to breed with harems of cows, but rarely duel to the death.
Bison and Her Calf
Photograph by Tom Murphy
Bison cows give birth after nine months and nurse their calves for about a year. Calves are able to stand shortly after birth, but remain vulnerable to wolves and bears until they reach maturity at the age of about three years.
Two Male Bison Fighting
Photograph by James L. Amos
Two male bison spar in a field. Males battle for mating primacy, but such contests rarely turn dangerous.
Herd of Bison
Photograph by Joel Sartore
Conservation programs at parks and zoos have combined forces with farmers, working to increase bison populations. Today there are about 200,000 bison in ranches and reserves.
Sean Gerrity hopes to create the largest wildlife reserve ever assembled in the continental United States.
Scientists estimate only about 3,000 wild tigers are left in the entire world. Meet the subspecies and see what threats each is facing.