Bisons are the symbol of Great Plains. Theodore Roosevelt National Park in North Dakota cares about their conservation and restoration, as calves are very important to the herds. Calving season usually begins in April. Newborn bisons are bright orange. They get up and start walking three hours after birth. During the first few weeks, they stay close to their mothers who are very protective during this time.
Calves are very playful and spend a lot of time with other babies in "nursery groups", under an eye of other cows in the herd. For the first three months, from April till June, the calves are the cutest. Three months later their coloration changes from orange-red to darker brown. In the same period, the hump and horns begin to form. Baby bison stays with its mother for about a year until a new calf is born.