American bison becomes the first national mammal of the US Agricultural Research Service

The US has adopted the bison as its national mammal, with President Barack Obama making it official by singing a law. The bald eagle will continue to enjoy the position of the national animal of the US.

The law, which regards the bison as a symbol for America's heritage as a whole, stated that the animal's history is "integrally linked with the economic and spiritual lives of many Indian tribes through trade and sacred ceremonies", Reuters reported.

The first national mammal status for the bison was achieved after a four-year push led by the Wildlife Conservation Society, which is a group associated with the Bronx Zoo in New York. In 1907, the zoo reportedly sent 15 captive-bred, native bison to the first US wildlife refuge in Oklahoma for preservation.

Millions of the four-legged beast once roamed across North America, particularly the Great Plains, but unregulated hunting pushed these mammals towards extinction. Their number had come down to mere hundreds by the late 19th century, the news source stated.

Less than 50 bison that survived were preserved in Yellowstone National Park under the care of the US Cavalry. Today, the national park houses about 4,900 of these mammals. The national park stretches across Wyoming, Montana and Idaho, where the mammal represents the largest band of wild, pure-bred bison.

Bison, also known as buffalo, are reportedly among the largest mammals found in North America, with males of the shaggy, hump-shouldered species weighing up to 2,000 pounds and about 6 feet tall.

The bison has graced the back of the US nickel for around 25 years and has also found a place on the US Interior Department seal since 1912. However, the government's policy of killing hundreds of these buffaloes every year when their numbers exceed a population target of 3,000 at Yellowstone has been mired by controversy. The policymakers claimed the killings were part of a precautionary measure against the spread of brucellosis disease.