American bison (Bison bison), which shaped the lifestyle of the Plains Indians and figured prominently in American history before they were brought to near extinction, were transplanted to Alaska from Montana in 1928. While bison were the most common large land mammal in Alaska thousands of years ago, all of Alaska's existing wild bison came from 20 animals released near Delta Junction. Natural emigration and transplants have now created additional herds at Copper River, ChitinaRiver, and Farewell. Small domestic herds are located at Healy, near Kodiak, and on PopovIsland. There were approximately 700 wild bison in the state in mid-1985.
General description: The bison is the largest native land mammal in North America. A full-grown bull stands 6 feet (1.8 m) at the shoulder, is up to 10 feet (3.3 m) long and can weigh more than a ton (907 kg). Full-grown cows are smaller but have been known to weigh over 1,200 pounds (544 kg). A bison's head and forequarters are massive and seem out of proportion to the smaller hind parts. A bison's backbone begins just ahead of the hips and reaches its maximum height above the front shoulder. From above the shoulder, the hump drops almost straight down to the neck.
The bison's horns curve upward. The horns of the bull are larger and heavier than the horns of the cow. In late fall, the bison's coat is a rich, dark brown. As winter progresses, the coat changes color and is much paler by spring. When the weather warms, the hair loosens and hangs in patches until it is completely shed and replaced with new hair by late spring. Hair on the chin resembles a goatee. Older animals tend to have more hair on their heads.
Life history: Most bison young are born in May, but calves are born from April to August or even later. Newly born calves have a reddish coat. They are able to stand when only 30 minutes old; within three hours of birth, they can run and kick their hind legs in the air. At about 6 days of age, calves start grazing. Their reddish-orange coat begins to darken at about 10 weeks, with the molt to dark brown complete about five weeks later.
Cows are sexually mature at 2 years of age and give birth to single calves twice in three years. The gestation period is approximately 270 days. On rare occasions, a mostly white or even albino calf has been born in the Delta herd, but none has ever reached maturity.
Bison in Alaska have been known to live to a relatively great age compared to other hoofed animals (ungulates). One tagged bull killed in the Copper River area was over 20 years old.
Bison are migratory animals by nature. Alaska's wild bison do not remain in single herds, but scatter alone or in groups ranging up to 50 animals or more. In the Delta Junction area, they move far up the DeltaRiver in early spring to secluded meadows where they calve. Around August they travel back downstream, eventually moving onto the DeltaJunctionBisonRange; and finally in late fall, onto farms where they remain throughout the winter. Here they sometimes cause damage to unharvested crops. Alaska's other wild bison herds also have seasonal movement patterns.
Bison move slowly while feeding and appear to be quite clumsy. This is pure deception, for when pursued the bison is fleet of foot and has great endurance. A mature bull eventually captured at Delta Junction jumped a seven-foot log fence from a standing position.